Android(安卓)Launcher全面剖析

Android Launcher全面剖析

首先来说说我为什么写这篇文章，最近公司要我负责搞Launcher，网上一查这方面的资料比较少，并且不全，研究起来相当困难，所以就写了这篇文章，希望对大家有帮助。这篇文章是相当长的，希望读者能耐心读下去，实际上也花了我很长时间来写。好了闲话少说，我们切入正题。

这篇文章我会讲以下Launcher内容：

Launcher UI总体架构

Launcher Res下的Layout

Launcher Res下的Xml文件

Launcher Manifest文件

Launcher 常用类介绍

Launcher 启动过程

Launcher widget添加过程

Launcher celllayout的介绍

一 Launcher UI总体架构

Home screen可以说是一个手机的最重要应用，就像一个门户网站的首页，直接决定了用户的第一印象。下面对home screen做一简要分析。

home screen的代码位于packages/apps/Launcher目录。从文件launcher.xml，workspace_screen.xml可获知home screen的UI结构如下图所示：

整个homescreen是一个包含三个child view的FrameLayout（com.android.launcher.DragLayer）。

第一个child就是桌面com.android.launcher.Workspace。这个桌面又包含三个child。每个child就对应一个桌面。这就是你在Android上看到的三个桌面。每个桌面上可以放置下列对象：应用快捷方式，appwidget和folder。

第二个child是一个SlidingDrawer控件，这个控件由两个子控件组成。一个是com.android.launcher.HandleView，就是Android桌面下方的把手，当点击这个把手时，另一个子控件，com.android.launcher.AllAppsGridView就会弹出，这个子控件列出系统中当前安装的所有类型为category.launcher的Activity。

第三个child是com.android.launcher.DeleteZone。当用户在桌面上长按一个widget时，把手位置就会出现一个垃圾桶形状的控件，就是这个控件。

在虚拟桌面上可以摆放四种类型的对象：
1. ITEM_SHORTCUT，应用快捷方式
2. ITEM_APPWIDGET，app widget
3. ITEM_LIVE_FOLDER，文件夹
4. ITEM_WALLPAPER，墙纸。

类AddAdapter（AddAdapter.java）列出了这四个类型对象。当用户在桌面空白处长按时，下列函数序列被执行：
Launcher::onLongClick -->
Launcher::showAddDialog -->
Launcher::showDialog(DIALOG_CREATE_SHORTCUT); -->
Launcher::onCreateDialog -->
Launcher::CreateShortcut::createDialog:这个函数创建一个弹出式对话框，询问用户是要添加什么（快捷方式，appwidget, 文件夹和墙纸）其内容就来自AddAdapter。

类Favorites(LauncherSettings.java)和类LauncherProvider定义了一个content provider，用来存储桌面上可以放置的几个对象，包括shortcut, search和clock等。

类DesktopItemsLoader负责将桌面上所有的对象从content provider中提取。

线程private ApplicationsLoader mApplicationsLoader负责从包管理器中获取系统中安装的应用列表。（之后显示在AllAppsGridView上）。ApplicationsLoader::run实现：
1）通过包管理器列出系统中所有类型为Launcher，action为MAIN的activity；
2）对每一个Activity,
a) 将Activity相关元数据信息，如title, icon, intent等缓存到appInfoCache；
b) 填充到ApplicationsAdapter 中。填充过程中用到了一些小技巧，每填充4（UI_NOTIFICATION_RATE）个activity更新一下相应view。

在Launcher::onCreate中，函数startLoaders被调用。而该函数接着调用loadApplications和loadUserItems，分别获取系统的应用列表，以及显示在桌面上的对象列表（快捷方式，appwidget，folder等）。

Launcher上排列的所有应用图标由AllAppsGridView对象呈现。这个对象是一个GridView。其对应的Adapter是ApplicationsAdapter，对应的model则是ApplicationInfo数组。数组内容是由ApplicationsLoader装载的。
private class ApplicationsLoader implements Runnable。

由Launcher中的AndroidManifest.xml可以看出整个Launcher的代码结构。

首先，是一些权限的声明。例如：

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"android.permission.CALL_PHONE" />
"android.permission.EXPAND_STATUS_BAR" />

这部分可以略过；

其次，Application的构成，如上图：

(1)Launcher：HomeScreen的Activity。

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"android.intent.action.MAIN" />
"android.intent.category.HOME"/>
"android.intent.category.DEFAULT" />
"android.intent.category.MONKEY" />

上面这段代码就标志着它是开机启动后Home的Activity。通过Launcher.java中onCreat()的分析我们可以大致把握屏幕的主要活动：

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protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//把xml文件的内容实例化到View中
mInflater = getLayoutInflater();
//监听应用程序控件改变事件
mAppWidgetManager = AppWidgetManager.getInstance(this);
mAppWidgetHost = new LauncherAppWidgetHost(this, APPWIDGET_HOST_ID);
mAppWidgetHost.startListening();
// 用于调试?
if (PROFILE_STARTUP) {
android.os.Debug.startMethodTracing("/sdcard/launcher");
}
//监听locale，mcc，mnc是否改变，如果改变，则重写新配置
//mcc：mobile country code(国家代码China 460); mnc：mobile network code(网络代码)
checkForLocaleChange();
/*This allows such applications to have a virtual wallpaper that is larger than the physical screen, matching the size of their workspace.*/
setWallpaperDimension();
//显示主屏幕UI元素，workspace,slidingdrawer(handleview and appgridview),deletezone
setContentView(R.layout.launcher);
//Finds all the views we need and configure them properly.
//完成workspace，slidingdrawer，deletezone的各种事件操作和监听
setupViews();
//Registers various intent receivers.
//允许其他应用对本应用的操作
registerIntentReceivers();
//Registers various content observers.
//例如，注册一个内容观察者跟踪喜爱的应用程序
registerContentObservers();
//重新保存前一个状态（目的??）
mSavedState = savedInstanceState;
restoreState(mSavedState);
//调试?
if (PROFILE_STARTUP) {
android.os.Debug.stopMethodTracing();
}
//Loads the list of installed applications in mApplications.
if (!mRestoring) {
startLoaders();
}
// For handling default keys??
mDefaultKeySsb = new SpannableStringBuilder();
Selection.setSelection(mDefaultKeySsb, 0);
}

protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //把xml文件的内容实例化到View中 mInflater = getLayoutInflater(); //监听应用程序控件改变事件 mAppWidgetManager = AppWidgetManager.getInstance(this); mAppWidgetHost = new LauncherAppWidgetHost(this, APPWIDGET_HOST_ID); mAppWidgetHost.startListening(); // 用于调试? if (PROFILE_STARTUP) { android.os.Debug.startMethodTracing("/sdcard/launcher"); } //监听locale，mcc，mnc是否改变，如果改变，则重写新配置 //mcc：mobile country code(国家代码China 460); mnc：mobile network code(网络代码) checkForLocaleChange(); /*This allows such applications to have a virtual wallpaper that is larger than the physical screen, matching the size of their workspace.*/ setWallpaperDimension(); //显示主屏幕UI元素，workspace,slidingdrawer(handleview and appgridview),deletezone setContentView(R.layout.launcher); //Finds all the views we need and configure them properly. //完成workspace，slidingdrawer，deletezone的各种事件操作和监听 setupViews(); //Registers various intent receivers. //允许其他应用对本应用的操作 registerIntentReceivers(); //Registers various content observers. //例如，注册一个内容观察者跟踪喜爱的应用程序 registerContentObservers(); //重新保存前一个状态（目的??） mSavedState = savedInstanceState; restoreState(mSavedState); //调试? if (PROFILE_STARTUP) { android.os.Debug.stopMethodTracing(); } //Loads the list of installed applications in mApplications. if (!mRestoring) { startLoaders(); } // For handling default keys?? mDefaultKeySsb = new SpannableStringBuilder(); Selection.setSelection(mDefaultKeySsb, 0); }

方法onActivityResult():完成在workspace上增加shortcut，appwidge和Livefolder；

方法onSaveInstantceState()和onRestoreInstanceState():为了防止Sensor、Land和Port布局自动切换时数据被置空，通过onSaveInstanceState方法可以保存当前窗口的状态，在即将布局切换前将当前的Activity压入历史堆栈。如果我们的Activity在后台没有因为运行内存吃紧被清理，则切换时回触发onRestoreIntanceState()。

(2)WallpaperChooser：设置墙纸。

同理我们从onCreat()作为入口来分析这个活动的主要功能。

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public void onCreate(Bundle icicle) {
super.onCreate(icicle);
//设置允许改变的窗口状态，需在 setContentView 之前调用
requestWindowFeature(Window.FEATURE_NO_TITLE);
/ /添加墙纸资源，将资源标识符加入到动态数组中
findWallpapers();
//显示墙纸设置屏幕的UI元素，Imageview,Gallery and Button(LinearLayout)
setContentView(R.layout.wallpaper_chooser);
//图片查看功能的实现
mGallery = (Gallery) findViewById(R.id.gallery);
mGallery.setAdapter(new ImageAdapter(this));
mGallery.setOnItemSelectedListener(this);
mGallery.setCallbackDuringFling(false);
//Button事件监听，点击选择setWallpaper(Resid)
findViewById(R.id.set).setOnClickListener(this);
mImageView = (ImageView) findViewById(R.id.wallpaper);
}

public void onCreate(Bundle icicle) { super.onCreate(icicle); //设置允许改变的窗口状态，需在 setContentView 之前调用 requestWindowFeature(Window.FEATURE_NO_TITLE); / /添加墙纸资源，将资源标识符加入到动态数组中 findWallpapers(); //显示墙纸设置屏幕的UI元素，Imageview,Gallery and Button(LinearLayout) setContentView(R.layout.wallpaper_chooser); //图片查看功能的实现 mGallery = (Gallery) findViewById(R.id.gallery); mGallery.setAdapter(new ImageAdapter(this)); mGallery.setOnItemSelectedListener(this); mGallery.setCallbackDuringFling(false); //Button事件监听，点击选择setWallpaper(Resid) findViewById(R.id.set).setOnClickListener(this); mImageView = (ImageView) findViewById(R.id.wallpaper); }

(3)default_searchable

对于home中任意的Acitivty，使能系统缺省Search模式，这样就可以使用android系统默认的search UI。

(4)InstallShortcutReceiver：

继承自BroadcastReceiver，重写onReceier()方法，对于发送来的Broadcast（这里指Intent）进行过滤（IntentFilt）并且响应（这里是InstallShortcut()）。这里分析下onReceive():

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public void onReceive(Context context, Intent data) {
//接受并过滤Intent
if (!ACTION_INSTALL_SHORTCUT.equals(data.getAction())) {
return;
}
//获取屏幕
int screen = Launcher.getScreen();
//安装快捷方式
if (!installShortcut(context, data, screen)) {
//如果屏幕已满，搜寻其他屏幕
for (int i = 0; i < Launcher.SCREEN_COUNT; i++) {
if (i != screen && installShortcut(context, data, i)) break;
}
}
}

public void onReceive(Context context, Intent data) { //接受并过滤Intent if (!ACTION_INSTALL_SHORTCUT.equals(data.getAction())) { return; } //获取屏幕 int screen = Launcher.getScreen(); //安装快捷方式 if (!installShortcut(context, data, screen)) { //如果屏幕已满，搜寻其他屏幕 for (int i = 0; i < Launcher.SCREEN_COUNT; i++) { if (i != screen && installShortcut(context, data, i)) break; } } }

其中IntallShortcut()方法：首先，对传入的坐标进行判断（findEmptyCell()）,如果是空白位置，则可以放置快捷方式；其次，缺省情况下，我们允许创建重复的快捷方式，具体创建过程（addShortcut()）就是把快捷方式的信息传入数据库（addItemToDatabase()）。

(5)UninstallShortcutReceiver：

同理，UninstallShortcutReceiver()继承自BroadcastReceiver()，实现onReceiver()方法。定义一个ContentResolver对象完成对数据库的访问和操作（通过URI定位），进而删除快捷方式。

(6)LauncherProvider：

继承自ContentProvider()，主要是建立一个数据库来存放HomeScreen中的数据信息，并通过内容提供者来实现其他应用对launcher中数据的访问和操作。

重写了ContentProvider()中的方法：

getType():返回数据类型。如果有自定义的全新类型，通过此方法完成数据的访问。

query():查询数据。传入URI，返回一个Cursor对象，通过Cursor完成对数据库数据的遍历访问。

Insert():插入一条数据。

bulkInsert():大容量数据的插入。

delete():删除一条数据。

update():更改一条数据。

sendNotify():发送通知。

类DatabaseHelper继承自一个封装类SQLiteOpenHelper(),方便了数据库的管理和维护。

重写的方法：

onCreate():创建一个表。其中db.execSQL()方法执行一条SQL语句，通过一条字符串执行相关的操作。当然，对SQL基本语句应该了解。

onUpgrade():升级数据库。

对HomeScreen数据库操作的一些方法：

addClockWidget(),addSearchWidget,addShortcut,addAppShortcut,

loadFavorites(),launcherAppWidgetBinder(),convertWidget(),updateContactsShortcuts(),

copyFromCursor()

补充：

类AddAdapter（AddAdapter.java）列出了这四个类型对象。当用户在桌面空白处长按时，下列函数序列被执行：

Launcher::onLongClick -->

Launcher::showAddDialog -->

Launcher::showDialog(DIALOG_CREATE_SHORTCUT); -->

Launcher::onCreateDialog -->

Launcher::CreateShortcut::createDialog:这个函数创建一个弹出式对话框，询问用户是要添加什么（快捷方式，appwidget, 文件夹和墙纸）其内容就来自AddAdapter。

类DesktopItemsLoader负责将桌面上所有的对象从content provider中提取。

线程private ApplicationsLoader mApplicationsLoader负责从包管理器中获取系统中安装的应用列表。（之后显示在AllAppsGridView上）。ApplicationsLoader::run实现：
1）通过包管理器列出系统中所有类型为Launcher，action为MAIN的activity；
2）对每一个Activity,
a) 将Activity相关元数据信息，如title, icon, intent等缓存到appInfoCache；
b) 填充到ApplicationsAdapter 中。填充过程中用到了一些小技巧，每填充4（UI_NOTIFICATION_RATE）个activity更新一下相应view。

在Launcher::onCreate中，函数startLoaders被调用。而该函数接着调用loadApplications和loadUserItems，分别获取系统的应用列表，以及显示在桌面上的对象列表（快捷方式，appwidget，folder等）。
Launcher上排列的所有应用图标由AllAppsGridView对象呈现。这个对象是一个GridView。其对应的Adapter是ApplicationsAdapter，对应的model则是ApplicationInfo数组。数组内容是由ApplicationsLoader装载的。

二 Launcher Res下的Layout

现在我们来看res目录里的布局文件，布局文件都放在layout*目录里。
本以为launcher的layout都放在layout目录里，由于屏幕放置方式的不同会对桌面造成一定的影响，所以google的Android项目组就决定因地制宜。比如当你横着放置屏幕的时候就会使用layout-land目录里的文件来对系统launcher进行布局，竖着屏幕的时候会使用layout-port内的布局文件来对launcher来布局。
横竖屏幕切换之际，会重新进行布局。那我们就以layout-land目录为例来看吧。
layout-land/launcuer.xml

复制到剪贴板 XML/HTML代码

<?xml version="1.0" encoding="utf-8"?>
<permission
android:name="com.android.zkx_launcher.permission.INSTALL_SHORTCUT"
android:permissionGroup="android.permission-group.SYSTEM_TOOLS"
android:protectionLevel="normal"
android:label="@string/permlab_install_shortcut"
android:description="@string/permdesc_install_shortcut" />
<permission
android:name="com.android.zkx_launcher.permission.UNINSTALL_SHORTCUT"
android:permissionGroup="android.permission-group.SYSTEM_TOOLS"
android:protectionLevel="normal"
android:label="@string/permlab_uninstall_shortcut"
android:description="@string/permdesc_uninstall_shortcut"/>
<permission
android:name="com.android.zkx_launcher.permission.READ_SETTINGS"
android:permissionGroup="android.permission-group.SYSTEM_TOOLS"
android:protectionLevel="normal"
android:label="@string/permlab_read_settings"
android:description="@string/permdesc_read_settings"/>
<permission
android:name="com.android.zkx_launcher.permission.WRITE_SETTINGS"
android:permissionGroup="android.permission-group.SYSTEM_TOOLS"
android:protectionLevel="normal"
android:label="@string/permlab_write_settings"
android:description="@string/permdesc_write_settings"/>
<uses-permission android:name="android.permission.CALL_PHONE" />
<uses-permission android:name="android.permission.EXPAND_STATUS_BAR" />
<uses-permission android:name="android.permission.GET_TASKS" />
<uses-permission android:name="android.permission.READ_CONTACTS"/>
<uses-permission android:name="android.permission.SET_WALLPAPER" />
<uses-permission android:name="android.permission.SET_WALLPAPER_HINTS" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />
<uses-permission android:name="android.permission.BIND_APPWIDGET" />
<uses-permission android:name="com.android.launcher.permission.READ_SETTINGS" />
<uses-permission android:name="com.android.launcher.permission.WRITE_SETTINGS" />
<application
android:name="LauncherApplication"
android:process="@string/process"
android:label="@string/application_name"
android:icon="@drawable/ic_launcher_home">
<activity
android:name="Launcher"
android:launchMode="singleTask"
android:clearTaskOnLaunch="true"
android:stateNotNeeded="true"
android:theme="@style/Theme"
android:screenOrientation="nosensor"
android:windowSoftInputMode="stateUnspecified|adjustPan">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.HOME" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.MONKEY"/>
intent-filter>
activity>
<activity
android:name="WallpaperChooser"
android:label="@string/pick_wallpaper"
android:icon="@drawable/ic_launcher_wallpaper"
android:screenOrientation="nosensor"
android:finishOnCloseSystemDialogs="true">
<intent-filter>
<action android:name="android.intent.action.SET_WALLPAPER" />
<category android:name="android.intent.category.DEFAULT" />
intent-filter>
activity>
<receiver
android:name="InstallShortcutReceiver"
android:permission="com.android.zkx_launcher.permission.INSTALL_SHORTCUT">
<intent-filter>
<action android:name="com.android.zkx_launcher.action.INSTALL_SHORTCUT" />
intent-filter>
receiver>
<receiver
android:name="UninstallShortcutReceiver"
android:permission="com.android.zkx_launcher.permission.UNINSTALL_SHORTCUT">
<intent-filter>
<action android:name="com.android.zkx_launcher.action.UNINSTALL_SHORTCUT" />
intent-filter>
receiver>
<provider
android:name="LauncherProvider"
android:authorities="com.android.zkx_launcher.settings"
android:writePermission="com.android.zkx_launcher.permission.WRITE_SETTINGS"
android:readPermission="com.android.zkx_launcher.permission.READ_SETTINGS" />
application>
manifest>

三 Launcher Res下的Xml文件

Res/xml下有两个xml文件，default_workspace.xml&&default_wallpaper.xml

             Andorid这个默认壁纸不在launcher里，在源码中frameworks/base/core/res/res /drawable/default_wallpaper.jpg.
另frameworks/base/core/res/res路径下包含很多default资源。如果需要修改默认设置可以尝试到这里来找一找




            launcher:packageName="com.google.android.apps.genie.geniewidget"
        launcher:className="com.google.android.apps.genie.geniewidget.miniwidget.MiniWidgetProvider"
        launcher:screen="1"
        launcher:x="0"
        launcher:y="0"
        launcher:spanX="4"
        launcher:spanY="1" />
#天气新闻时钟插件
#packageName：widget的packageName
#className　：实现 widget的 receiver 类的名称.
#launcher:container 放置的位置（只能为desktop）
#screen ：在哪一个screen添加

#x，y: 在screen中的位置
#launcher:spanX：在x方向上所占格数
#launcher:spanY：在y方向上所占格数


            launcher:screen="2"
        launcher:x="0"
        launcher:y="0" />

            launcher:packageName="com.android.protips"
        launcher:className="com.android.protips.ProtipWidget"
        launcher:screen="2"
        launcher:x="0"
        launcher:y="1"
        launcher:spanX="4"
    launcher:spanY="1 " />

            launcher:packageName="com.android.music"
        launcher:className="com.android.music.MediaAppWidgetProvider"
        launcher:screen="3"
        launcher:x="0"
        launcher:y="0"
        launcher:spanX="4"
        launcher:spanY="1" />

            launcher:packageName="com.android.vending"
        launcher:className="com.android.vending.MarketWidgetProvider"
        launcher:screen="3"
        launcher:x="1"
        launcher:y="1"
        launcher:spanX="2"
        launcher:spanY="2" />
#电子市场Android Market

四 Launcher Manifest文件 Launcher的AndroidManifest.xml文件有很多特殊性，分析一下就会理解整个程序的大概结构。
代码如下：

<manifestxmlns:android="http://schemas.android.com/apk/res/android"

package="net.sunniwell.launcher"

android:versionCode="1"android:versionName="1.0.1">

关于自定义权限，这是很好的例子，其他apk程序要想使用Launcher的功能必须添加这些权限，而这些权限都是在这里声明的。

这个是安装快捷方式的权限定义：

<permission

android:name="com.android.launcher.permission.INSTALL_SHORTCUT"

android:permissionGroup="android.permission-group.SYSTEM_TOOLS"

android:protectionLevel="normal"

android:label="@string/permlab_install_shortcut"

android:description="@string/permdesc_install_shortcut"/>

这个是卸载快捷方式的权限定义：

<permission

android:name="com.android.launcher.permission.UNINSTALL_SHORTCUT"

android:permissionGroup="android.permission-group.SYSTEM_TOOLS"

android:protectionLevel="normal"

android:label="@string/permlab_uninstall_shortcut"

android:description="@string/permdesc_uninstall_shortcut"/>

这个是读取launcher.db内容的权限定义：

<permission

android:name="net.sunniwell.launcher.permission.READ_SETTINGS"

android:permissionGroup="android.permission-group.SYSTEM_TOOLS"

android:protectionLevel="normal"

android:label="@string/permlab_read_settings"

android:description="@string/permdesc_read_settings"/>

这个是修改和删除launcher.db内容的权限定义：

<permission

android:name="net.sunniwell.launcher.permission.WRITE_SETTINGS"

android:permissionGroup="android.permission-group.SYSTEM_TOOLS"

android:protectionLevel="normal"

android:label="@string/permlab_write_settings"

android:description="@string/permdesc_write_settings"/>

这些是Launcher的权限声明，通过这些就能看出launcher的大概功能了：

打电话权限：

<uses-permissionandroid:name="android.permission.CALL_PHONE"/>

使用状态栏权限：

<uses-permissionandroid:name="android.permission.EXPAND_STATUS_BAR"/>

获取当前或最近运行的任务的信息的权限：

<uses-permissionandroid:name="android.permission.GET_TASKS"/>

读取通信录权限:

<uses-permissionandroid:name="android.permission.READ_CONTACTS"/>

设置壁纸权限：

<uses-permissionandroid:name="android.permission.SET_WALLPAPER"/>

允许程序设置壁纸hits的权限：

<uses-permissionandroid:name="android.permission.SET_WALLPAPER_HINTS"/>

使用震动功能权限：

<uses-permissionandroid:name="android.permission.VIBRATE"/>

修改删除launcher.db内容权限：

<uses-permissionandroid:name="android.permission.WRITE_SETTINGS"/>

绑定widget权限：

<uses-permissionandroid:name="android.permission.BIND_APPWIDGET"/>

读取launcher.db内容权限：

<uses-permissionandroid:name="net.sunniwell.launcher.permission.READ_SETTINGS"/>

修改删除launcher.db内容权限：

<uses-permissionandroid:name="net.sunniwell.launcher.permission.WRITE_SETTINGS"/>

读写外部存储设备权限：

<uses-permissionandroid:name="android.permission.WRITE_EXTERNAL_STORAGE">uses-permission>

<application

android:name="LauncherApplication"

activity应该运行的进程的名字：

android:process="android.process.acore"

android:label="@string/application_name"

android:icon="@drawable/swicon">

<activity

android:name="Launcher"

是否

android:launchMode="singleTask"

android:clearTaskOnLaunch="true"

这个activity是否在被杀死或者重启后能恢复原来的状态：

android:stateNotNeeded="true"

android:theme="@style/Theme"

android:screenOrientation="landscape"

android:windowSoftInputMode="stateUnspecified|adjustPan">

<intent-filter>

<actionandroid:name="android.intent.action.MAIN"/>

<categoryandroid:name="android.intent.category.LAUNCHER"/>

桌面应用的标记：

<categoryandroid:name="android.intent.category.HOME"/>

<categoryandroid:name="android.intent.category.DEFAULT"/>

自动化测试工具Monkey的标记，待研究…

<categoryandroid:name="android.intent.category.MONKEY"/>

intent-filter>

activity>

选择壁纸的activity:

<activity

android:name="WallpaperChooser"

android:label="@string/pick_wallpaper"

android:icon="@drawable/ic_launcher_gallery">

设置壁纸的intent-filter：

<intent-filter>

<actionandroid:name="android.intent.action.SET_WALLPAPER"/>

<categoryandroid:name="android.intent.category.DEFAULT"/>

intent-filter>

搜索的activity：

activity>

<meta-data

android:name="android.app.default_searchable"

android:value="*"/>

安装快捷方式的广播接收器：

<receiver

android:name=".InstallShortcutReceiver"

android:permission="com.android.launcher.permission.INSTALL_SHORTCUT">

<intent-filter>

<actionandroid:name="com.android.launcher.action.INSTALL_SHORTCUT"/>

intent-filter>

receiver>

卸载快捷方式的广播接收器：

<receiver

android:name=".UninstallShortcutReceiver"

android:permission="com.android.launcher.permission.UNINSTALL_SHORTCUT">

<intent-filter>

<actionandroid:name="com.android.launcher.action.UNINSTALL_SHORTCUT"/>

intent-filter>

receiver>

声明ContentProvider，用于对launcher.db操作：

<provider

android:name="SWLauncherProvider"

android:authorities="net.sunniwell.launcher.settings"

android:writePermission="net.sunniwell.launcher.permission.WRITE_SETTINGS"

android:readPermission="net.sunniwell.launcher.permission.READ_SETTINGS"/>

application>

<uses-sdkandroid:minSdkVersion="4"/>

manifest>
说明：
1.
标签头部还应声明：
android:sharedUserId="android.uid.shared"，作用是获得系统权限，但是这样的程序属性只能在build整个系统时放进去（就是系统软件）才起作用，手动安装是没有权限的。

五 Launcher 常用类介绍

AddAdapter: 维护了 live fold , widget , shortcut , wallpaper 4 个 ListItem ，长按桌面会显示该列表

AllAppsGridView ：显示 APP 的网格

ApplicationInfo ：一个可启动的应用

ApplicationsAdapter ： gridview 的 adapter

BubbleTextView: 一个定制了的 textview

CellLayout: 屏幕网格化

DeleteZone ： UI 的一部分

DragController ， dragscroller, dragsource, droptarget: 支持拖拽操作

DragLayer ：内部支持拖拽的 viewgroup

FastBitmapDrawable ：工具

Folder ： Icons 的集合

FolderIcon: 出现在 workspace 的 icon 代表了一个 folder

FolderInfo: ItemInfo 子类

HandleView ：一个 imageview 。

InstallShortcutReceiver ， UninstallShortcutReceiver ：一个 broadcastrecier

ItemInfo: 代表 Launcher 中一个 Item （例如 folder ）

Launcher: Launcher 程序的主窗口

LauncherApplication ：在 VM 中设置参数

LauncherAppWidgetHost ， LauncherAppWidgetHostView ，： Widget 相关

LauncherModel ： MVC 中的 M

LauncherProvider ：一个 contentprovider ，为 Launcher 存储信息

LauncherSettings: 设置相关的工具

LiveFolder ， LiveFolderAdapter ， LiveFolderIcon ， LiveFolderInfo ： livefolder 相关

Search ：搜索

UserFolder ， UserFolderInfo ：文件夹包含 applications ,shortcuts

Utilities: 小工具

WallpaperChooser ：选择 wallpaper 的 activity

Workspace: 屏幕上的一块区域

widget : 代表启动的 widget 实例，例如搜索

总结

1) Launcher中实现了MVC模式（M：launchermode , V:draglayer ,C: launcher），以此为主线，可以得到 Launcher对各个组件管理的细节（如drag的实现）。

六 Launcher 起动过程

Android系统在启动时会安装应用程序，这些应用程序安装好之后，还需要有一个Home应用程序来负责把它们在桌面上展示出来，在Android系统中，这个默认的Home应用程序就是Launcher了，我将详细分析Launcher应用程序的启动过程。

Android系统的Home应用程序Launcher是由ActivityManagerService启动的，而ActivityManagerService和PackageManagerService一样，都是在开机时由SystemServer组件启动的，SystemServer组件首先是启动ePackageManagerServic，由它来负责安装系统的应用程序，系统中的应用程序安装好了以后，SystemServer组件接下来就要通过ActivityManagerService来启动Home应用程序Launcher了，Launcher在启动的时候便会通过PackageManagerServic把系统中已经安装好的应用程序以快捷图标的形式展示在桌面上，这样用户就可以使用这些应用程序了。

下面详细分析每一个步骤。

Step 1. SystemServer.main

这个函数定义在frameworks/base/services/java/com/android/server/SystemServer.java文件中：

view plain copy to clipboard print ?

public class SystemServer
{
......
native public static void init1(String[] args);
......
public static void main(String[] args) {
......
init1(args);
......
}
......
}

public class SystemServer { ...... native public static void init1(String[] args); ...... public static void main(String[] args) { ...... init1(args); ...... } ...... } SystemServer组件是由Zygote进程负责启动的，启动的时候就会调用它的main函数，这个函数主要调用了JNI方法init1来做一些系统初始化的工作。

Step 2. SystemServer.init1

这个函数是一个JNI方法，实现在 frameworks/base/services/jni/com_android_server_SystemServer.cpp文件中：

view plain copy to clipboard print ?

namespace android {
extern "C" int system_init();
static void android_server_SystemServer_init1(JNIEnv* env, jobject clazz)
{
system_init();
}
/*
* JNI registration.
*/
static JNINativeMethod gMethods[] = {
/* name, signature, funcPtr */
{ "init1", "([Ljava/lang/String;)V", (void*) android_server_SystemServer_init1 },
};
int register_android_server_SystemServer(JNIEnv* env)
{
return jniRegisterNativeMethods(env, "com/android/server/SystemServer",
gMethods, NELEM(gMethods));
}
}; // namespace android

namespace android { extern "C" int system_init(); static void android_server_SystemServer_init1(JNIEnv* env, jobject clazz) { system_init(); } /* * JNI registration. */ static JNINativeMethod gMethods[] = { /* name, signature, funcPtr */ { "init1", "([Ljava/lang/String;)V", (void*) android_server_SystemServer_init1 }, }; int register_android_server_SystemServer(JNIEnv* env) { return jniRegisterNativeMethods(env, "com/android/server/SystemServer", gMethods, NELEM(gMethods)); } }; // namespace android 这个函数很简单，只是调用了system_init函数来进一步执行操作。

Step 3. libsystem_server.system_init

函数system_init实现在libsystem_server库中，源代码位于frameworks/base/cmds/system_server/library/system_init.cpp文件中：

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extern "C" status_t system_init()
{
LOGI("Entered system_init()");
sp proc(ProcessState::self());
sp sm = defaultServiceManager();
LOGI("ServiceManager: %p\n", sm.get());
sp grim = new GrimReaper();
sm->asBinder()->linkToDeath(grim, grim.get(), 0);
char propBuf[PROPERTY_VALUE_MAX];
property_get("system_init.startsurfaceflinger", propBuf, "1");
if (strcmp(propBuf, "1") == 0) {
// Start the SurfaceFlinger
SurfaceFlinger::instantiate();
}
// Start the sensor service
SensorService::instantiate();
// On the simulator, audioflinger et al don't get started the
// same way as on the device, and we need to start them here
if (!proc->supportsProcesses()) {
// Start the AudioFlinger
AudioFlinger::instantiate();
// Start the media playback service
MediaPlayerService::instantiate();
// Start the camera service
CameraService::instantiate();
// Start the audio policy service
AudioPolicyService::instantiate();
}
// And now start the Android runtime. We have to do this bit
// of nastiness because the Android runtime initialization requires
// some of the core system services to already be started.
// All other servers should just start the Android runtime at
// the beginning of their processes's main(), before calling
// the init function.
LOGI("System server: starting Android runtime.\n");
AndroidRuntime* runtime = AndroidRuntime::getRuntime();
LOGI("System server: starting Android services.\n");
runtime->callStatic("com/android/server/SystemServer", "init2");
// If running in our own process, just go into the thread
// pool. Otherwise, call the initialization finished
// func to let this process continue its initilization.
if (proc->supportsProcesses()) {
LOGI("System server: entering thread pool.\n");
ProcessState::self()->startThreadPool();
IPCThreadState::self()->joinThreadPool();
LOGI("System server: exiting thread pool.\n");
}
return NO_ERROR;
}

extern "C" status_t system_init() { LOGI("Entered system_init()"); sp proc(ProcessState::self()); sp sm = defaultServiceManager(); LOGI("ServiceManager: %p\n", sm.get()); sp grim = new GrimReaper(); sm->asBinder()->linkToDeath(grim, grim.get(), 0); char propBuf[PROPERTY_VALUE_MAX]; property_get("system_init.startsurfaceflinger", propBuf, "1"); if (strcmp(propBuf, "1") == 0) { // Start the SurfaceFlinger SurfaceFlinger::instantiate(); } // Start the sensor service SensorService::instantiate(); // On the simulator, audioflinger et al don't get started the // same way as on the device, and we need to start them here if (!proc->supportsProcesses()) { // Start the AudioFlinger AudioFlinger::instantiate(); // Start the media playback service MediaPlayerService::instantiate(); // Start the camera service CameraService::instantiate(); // Start the audio policy service AudioPolicyService::instantiate(); } // And now start the Android runtime. We have to do this bit // of nastiness because the Android runtime initialization requires // some of the core system services to already be started. // All other servers should just start the Android runtime at // the beginning of their processes's main(), before calling // the init function. LOGI("System server: starting Android runtime.\n"); AndroidRuntime* runtime = AndroidRuntime::getRuntime(); LOGI("System server: starting Android services.\n"); runtime->callStatic("com/android/server/SystemServer", "init2"); // If running in our own process, just go into the thread // pool. Otherwise, call the initialization finished // func to let this process continue its initilization. if (proc->supportsProcesses()) { LOGI("System server: entering thread pool.\n"); ProcessState::self()->startThreadPool(); IPCThreadState::self()->joinThreadPool(); LOGI("System server: exiting thread pool.\n"); } return NO_ERROR; } 这个函数首先会初始化SurfaceFlinger、SensorService、AudioFlinger、MediaPlayerService、CameraService和AudioPolicyService这几个服务，然后就通过系统全局唯一的AndroidRuntime实例变量runtime的callStatic来调用SystemServer的init2函数了。关于这个AndroidRuntime实例变量runtime的相关资料，可能参考前面一篇文章 Android应用程序进程启动过程的源代码分析一文。

Step 4. AndroidRuntime.callStatic

这个函数定义在frameworks/base/core/jni/AndroidRuntime.cpp文件中：

view plain copy to clipboard print ?

/*
* Call a static Java Programming Language function that takes no arguments and returns void.
*/
status_t AndroidRuntime::callStatic(const char* className, const char* methodName)
{
JNIEnv* env;
jclass clazz;
jmethodID methodId;
env = getJNIEnv();
if (env == NULL)
return UNKNOWN_ERROR;
clazz = findClass(env, className);
if (clazz == NULL) {
LOGE("ERROR: could not find class '%s'\n", className);
return UNKNOWN_ERROR;
}
methodId = env->GetStaticMethodID(clazz, methodName, "()V");
if (methodId == NULL) {
LOGE("ERROR: could not find method %s.%s\n", className, methodName);
return UNKNOWN_ERROR;
}
env->CallStaticVoidMethod(clazz, methodId);
return NO_ERROR;
}

/* * Call a static Java Programming Language function that takes no arguments and returns void. */ status_t AndroidRuntime::callStatic(const char* className, const char* methodName) { JNIEnv* env; jclass clazz; jmethodID methodId; env = getJNIEnv(); if (env == NULL) return UNKNOWN_ERROR; clazz = findClass(env, className); if (clazz == NULL) { LOGE("ERROR: could not find class '%s'\n", className); return UNKNOWN_ERROR; } methodId = env->GetStaticMethodID(clazz, methodName, "()V"); if (methodId == NULL) { LOGE("ERROR: could not find method %s.%s\n", className, methodName); return UNKNOWN_ERROR; } env->CallStaticVoidMethod(clazz, methodId); return NO_ERROR; } 这个函数调用由参数className指定的java类的静态成员函数，这个静态成员函数是由参数methodName指定的。上面传进来的参数className的值为"com/android/server/SystemServer"，而参数methodName的值为"init2"，因此，接下来就会调用SystemServer类的init2函数了。

Step 5. SystemServer.init2

这个函数定义在frameworks/base/services/java/com/android/server/SystemServer.java文件中：

view plain copy to clipboard print ?

public class SystemServer
{
......
public static final void init2() {
Slog.i(TAG, "Entered the Android system server!");
Thread thr = new ServerThread();
thr.setName("android.server.ServerThread");
thr.start();
}
}

public class SystemServer { ...... public static final void init2() { Slog.i(TAG, "Entered the Android system server!"); Thread thr = new ServerThread(); thr.setName("android.server.ServerThread"); thr.start(); } } 这个函数创建了一个ServerThread线程，PackageManagerService服务就是这个线程中启动的了。这里调用了ServerThread实例thr的start函数之后，下面就会执行这个实例的run函数了。

Step 6. ServerThread.run

这个函数定义在frameworks/base/services/java/com/android/server/SystemServer.java文件中：

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class ServerThread extends Thread {
......
@Override
public void run() {
......
IPackageManager pm = null;
......
// Critical services...
try {
......
Slog.i(TAG, "Package Manager");
pm = PackageManagerService.main(context,
factoryTest != SystemServer.FACTORY_TEST_OFF);
......
} catch (RuntimeException e) {
Slog.e("System", "Failure starting core service", e);
}
......
}
......
}

class ServerThread extends Thread { ...... @Override public void run() { ...... IPackageManager pm = null; ...... // Critical services... try { ...... Slog.i(TAG, "Package Manager"); pm = PackageManagerService.main(context, factoryTest != SystemServer.FACTORY_TEST_OFF); ...... } catch (RuntimeException e) { Slog.e("System", "Failure starting core service", e); } ...... } ...... } 这个函数除了启动PackageManagerService服务之外，还启动了其它很多的服务，例如在前面学习Activity和Service的几篇文章中经常看到的ActivityManagerService服务，有兴趣的读者可以自己研究一下。 Step 7. ActivityManagerService.main

这个函数定义在frameworks/base/services/java/com/android/server/am/ActivityManagerServcie.java文件中：

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public final class ActivityManagerService extends ActivityManagerNative
implements Watchdog.Monitor, BatteryStatsImpl.BatteryCallback {
......
public static final Context main(int factoryTest) {
AThread thr = new AThread();
thr.start();
synchronized (thr) {
while (thr.mService == null) {
try {
thr.wait();
} catch (InterruptedException e) {
}
}
}
ActivityManagerService m = thr.mService;
mSelf = m;
ActivityThread at = ActivityThread.systemMain();
mSystemThread = at;
Context context = at.getSystemContext();
m.mContext = context;
m.mFactoryTest = factoryTest;
m.mMainStack = new ActivityStack(m, context, true);
m.mBatteryStatsService.publish(context);
m.mUsageStatsService.publish(context);
synchronized (thr) {
thr.mReady = true;
thr.notifyAll();
}
m.startRunning(null, null, null, null);
return context;
}
......
}

public final class ActivityManagerService extends ActivityManagerNative implements Watchdog.Monitor, BatteryStatsImpl.BatteryCallback { ...... public static final Context main(int factoryTest) { AThread thr = new AThread(); thr.start(); synchronized (thr) { while (thr.mService == null) { try { thr.wait(); } catch (InterruptedException e) { } } } ActivityManagerService m = thr.mService; mSelf = m; ActivityThread at = ActivityThread.systemMain(); mSystemThread = at; Context context = at.getSystemContext(); m.mContext = context; m.mFactoryTest = factoryTest; m.mMainStack = new ActivityStack(m, context, true); m.mBatteryStatsService.publish(context); m.mUsageStatsService.publish(context); synchronized (thr) { thr.mReady = true; thr.notifyAll(); } m.startRunning(null, null, null, null); return context; } ...... } 这个函数首先通过AThread线程对象来内部创建了一个ActivityManagerService实例，然后将这个实例保存其成员变量mService中，接着又把这个ActivityManagerService实例保存在ActivityManagerService类的静态成员变量mSelf中，最后初始化其它成员变量，就结束了。

Step 8. PackageManagerService.main

这个函数定义在frameworks/base/services/java/com/android/server/PackageManagerService.java文件中：

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class PackageManagerService extends IPackageManager.Stub {
......
public static final IPackageManager main(Context context, boolean factoryTest) {
PackageManagerService m = new PackageManagerService(context, factoryTest);
ServiceManager.addService("package", m);
return m;
}
......
}

class PackageManagerService extends IPackageManager.Stub { ...... public static final IPackageManager main(Context context, boolean factoryTest) { PackageManagerService m = new PackageManagerService(context, factoryTest); ServiceManager.addService("package", m); return m; } ...... } 这个函数创建了一个PackageManagerService服务实例，然后把这个服务添加到ServiceManager中去，ServiceManager是Android系统Binder进程间通信机制的守护进程，负责管理系统中的Binder对象，在创建这个PackageManagerService服务实例时，会在PackageManagerService类的构造函数中开始执行安装应用程序的过程：

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class PackageManagerService extends IPackageManager.Stub {
......
public PackageManagerService(Context context, boolean factoryTest) {
......
synchronized (mInstallLock) {
synchronized (mPackages) {
......
File dataDir = Environment.getDataDirectory();
mAppDataDir = new File(dataDir, "data");
mSecureAppDataDir = new File(dataDir, "secure/data");
mDrmAppPrivateInstallDir = new File(dataDir, "app-private");
......
mFrameworkDir = new File(Environment.getRootDirectory(), "framework");
mDalvikCacheDir = new File(dataDir, "dalvik-cache");
......
// Find base frameworks (resource packages without code).
mFrameworkInstallObserver = new AppDirObserver(
mFrameworkDir.getPath(), OBSERVER_EVENTS, true);
mFrameworkInstallObserver.startWatching();
scanDirLI(mFrameworkDir, PackageParser.PARSE_IS_SYSTEM
| PackageParser.PARSE_IS_SYSTEM_DIR,
scanMode | SCAN_NO_DEX, 0);
// Collect all system packages.
mSystemAppDir = new File(Environment.getRootDirectory(), "app");
mSystemInstallObserver = new AppDirObserver(
mSystemAppDir.getPath(), OBSERVER_EVENTS, true);
mSystemInstallObserver.startWatching();
scanDirLI(mSystemAppDir, PackageParser.PARSE_IS_SYSTEM
| PackageParser.PARSE_IS_SYSTEM_DIR, scanMode, 0);
// Collect all vendor packages.
mVendorAppDir = new File("/vendor/app");
mVendorInstallObserver = new AppDirObserver(
mVendorAppDir.getPath(), OBSERVER_EVENTS, true);
mVendorInstallObserver.startWatching();
scanDirLI(mVendorAppDir, PackageParser.PARSE_IS_SYSTEM
| PackageParser.PARSE_IS_SYSTEM_DIR, scanMode, 0);
mAppInstallObserver = new AppDirObserver(
mAppInstallDir.getPath(), OBSERVER_EVENTS, false);
mAppInstallObserver.startWatching();
scanDirLI(mAppInstallDir, 0, scanMode, 0);
mDrmAppInstallObserver = new AppDirObserver(
mDrmAppPrivateInstallDir.getPath(), OBSERVER_EVENTS, false);
mDrmAppInstallObserver.startWatching();
scanDirLI(mDrmAppPrivateInstallDir, PackageParser.PARSE_FORWARD_LOCK,
scanMode, 0);
......
}
}
}
......
}

class PackageManagerService extends IPackageManager.Stub { ...... public PackageManagerService(Context context, boolean factoryTest) { ...... synchronized (mInstallLock) { synchronized (mPackages) { ...... File dataDir = Environment.getDataDirectory(); mAppDataDir = new File(dataDir, "data"); mSecureAppDataDir = new File(dataDir, "secure/data"); mDrmAppPrivateInstallDir = new File(dataDir, "app-private"); ...... mFrameworkDir = new File(Environment.getRootDirectory(), "framework"); mDalvikCacheDir = new File(dataDir, "dalvik-cache"); ...... // Find base frameworks (resource packages without code). mFrameworkInstallObserver = new AppDirObserver( mFrameworkDir.getPath(), OBSERVER_EVENTS, true); mFrameworkInstallObserver.startWatching(); scanDirLI(mFrameworkDir, PackageParser.PARSE_IS_SYSTEM | PackageParser.PARSE_IS_SYSTEM_DIR, scanMode | SCAN_NO_DEX, 0); // Collect all system packages. mSystemAppDir = new File(Environment.getRootDirectory(), "app"); mSystemInstallObserver = new AppDirObserver( mSystemAppDir.getPath(), OBSERVER_EVENTS, true); mSystemInstallObserver.startWatching(); scanDirLI(mSystemAppDir, PackageParser.PARSE_IS_SYSTEM | PackageParser.PARSE_IS_SYSTEM_DIR, scanMode, 0); // Collect all vendor packages. mVendorAppDir = new File("/vendor/app"); mVendorInstallObserver = new AppDirObserver( mVendorAppDir.getPath(), OBSERVER_EVENTS, true); mVendorInstallObserver.startWatching(); scanDirLI(mVendorAppDir, PackageParser.PARSE_IS_SYSTEM | PackageParser.PARSE_IS_SYSTEM_DIR, scanMode, 0); mAppInstallObserver = new AppDirObserver( mAppInstallDir.getPath(), OBSERVER_EVENTS, false); mAppInstallObserver.startWatching(); scanDirLI(mAppInstallDir, 0, scanMode, 0); mDrmAppInstallObserver = new AppDirObserver( mDrmAppPrivateInstallDir.getPath(), OBSERVER_EVENTS, false); mDrmAppInstallObserver.startWatching(); scanDirLI(mDrmAppPrivateInstallDir, PackageParser.PARSE_FORWARD_LOCK, scanMode, 0); ...... } } } ...... } 这里会调用scanDirLI函数来扫描移动设备上的下面这五个目录中的Apk文件：

/system/framework

/system/app

/vendor/app

/data/app

/data/app-private

Step 9. ActivityManagerService.setSystemProcess

这个函数定义在frameworks/base/services/java/com/android/server/am/ActivityManagerServcie.java文件中：

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public final class ActivityManagerService extends ActivityManagerNative
implements Watchdog.Monitor, BatteryStatsImpl.BatteryCallback {
......
public static void setSystemProcess() {
try {
ActivityManagerService m = mSelf;
ServiceManager.addService("activity", m);
ServiceManager.addService("meminfo", new MemBinder(m));
if (MONITOR_CPU_USAGE) {
ServiceManager.addService("cpuinfo", new CpuBinder(m));
}
ServiceManager.addService("permission", new PermissionController(m));
ApplicationInfo info =
mSelf.mContext.getPackageManager().getApplicationInfo(
"android", STOCK_PM_FLAGS);
mSystemThread.installSystemApplicationInfo(info);
synchronized (mSelf) {
ProcessRecord app = mSelf.newProcessRecordLocked(
mSystemThread.getApplicationThread(), info,
info.processName);
app.persistent = true;
app.pid = MY_PID;
app.maxAdj = SYSTEM_ADJ;
mSelf.mProcessNames.put(app.processName, app.info.uid, app);
synchronized (mSelf.mPidsSelfLocked) {
mSelf.mPidsSelfLocked.put(app.pid, app);
}
mSelf.updateLruProcessLocked(app, true, true);
}
} catch (PackageManager.NameNotFoundException e) {
throw new RuntimeException(
"Unable to find android system package", e);
}
}
......
}

public final class ActivityManagerService extends ActivityManagerNative implements Watchdog.Monitor, BatteryStatsImpl.BatteryCallback { ...... public static void setSystemProcess() { try { ActivityManagerService m = mSelf; ServiceManager.addService("activity", m); ServiceManager.addService("meminfo", new MemBinder(m)); if (MONITOR_CPU_USAGE) { ServiceManager.addService("cpuinfo", new CpuBinder(m)); } ServiceManager.addService("permission", new PermissionController(m)); ApplicationInfo info = mSelf.mContext.getPackageManager().getApplicationInfo( "android", STOCK_PM_FLAGS); mSystemThread.installSystemApplicationInfo(info); synchronized (mSelf) { ProcessRecord app = mSelf.newProcessRecordLocked( mSystemThread.getApplicationThread(), info, info.processName); app.persistent = true; app.pid = MY_PID; app.maxAdj = SYSTEM_ADJ; mSelf.mProcessNames.put(app.processName, app.info.uid, app); synchronized (mSelf.mPidsSelfLocked) { mSelf.mPidsSelfLocked.put(app.pid, app); } mSelf.updateLruProcessLocked(app, true, true); } } catch (PackageManager.NameNotFoundException e) { throw new RuntimeException( "Unable to find android system package", e); } } ...... } 这个函数首先是将这个ActivityManagerService实例添加到ServiceManager中去托管，这样其它地方就可以通过ServiceManager.getService接口来访问这个全局唯一的ActivityManagerService实例了，接着又通过调用mSystemThread.installSystemApplicationInfo函数来把应用程序框架层下面的android包加载进来，这里的mSystemThread是一个ActivityThread类型的实例变量，它是在上面的Step 7中创建的，后面就是一些其它的初始化工作了。

Step 10. ActivityManagerService.systemReady

这个函数是在上面的Step 6中的ServerThread.run函数在将系统中的一系列服务都初始化完毕之后才调用的，它定义在frameworks/base/services/java/com/android/server/am/ActivityManagerServcie.java文件中：

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public final class ActivityManagerService extends ActivityManagerNative
implements Watchdog.Monitor, BatteryStatsImpl.BatteryCallback {
......
public void systemReady(final Runnable goingCallback) {
......
synchronized (this) {
......
mMainStack.resumeTopActivityLocked(null);
}
}
......
}

public final class ActivityManagerService extends ActivityManagerNative implements Watchdog.Monitor, BatteryStatsImpl.BatteryCallback { ...... public void systemReady(final Runnable goingCallback) { ...... synchronized (this) { ...... mMainStack.resumeTopActivityLocked(null); } } ...... } 这个函数的内容比较多，这里省去无关的部分，主要关心启动Home应用程序的逻辑，这里就是通过mMainStack.resumeTopActivityLocked函数来启动Home应用程序的了，这里的mMainStack是一个ActivityStack类型的实例变量。

Step 11. ActivityStack.resumeTopActivityLocked

这个函数定义在frameworks/base/services/java/com/android/server/am/ActivityStack.java文件中：

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public class ActivityStack {
......
final boolean resumeTopActivityLocked(ActivityRecord prev) {
// Find the first activity that is not finishing.
ActivityRecord next = topRunningActivityLocked(null);
......
if (next == null) {
// There are no more activities! Let's just start up the
// Launcher...
if (mMainStack) {
return mService.startHomeActivityLocked();
}
}
......
}
......
}

public class ActivityStack { ...... final boolean resumeTopActivityLocked(ActivityRecord prev) { // Find the first activity that is not finishing. ActivityRecord next = topRunningActivityLocked(null); ...... if (next == null) { // There are no more activities! Let's just start up the // Launcher... if (mMainStack) { return mService.startHomeActivityLocked(); } } ...... } ...... } 这里调用函数topRunningActivityLocked返回的是当前系统Activity堆栈最顶端的Activity，由于此时还没有Activity被启动过，因此，返回值为null，即next变量的值为null，于是就调用mService.startHomeActivityLocked语句，这里的mService就是前面在Step 7中创建的ActivityManagerService实例了。

Step 12. ActivityManagerService.startHomeActivityLocked

这个函数定义在frameworks/base/services/java/com/android/server/am/ActivityManagerServcie.java文件中：

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public final class ActivityManagerService extends ActivityManagerNative
implements Watchdog.Monitor, BatteryStatsImpl.BatteryCallback {
......
boolean startHomeActivityLocked() {
......
Intent intent = new Intent(
mTopAction,
mTopData != null ? Uri.parse(mTopData) : null);
intent.setComponent(mTopComponent);
if (mFactoryTest != SystemServer.FACTORY_TEST_LOW_LEVEL) {
intent.addCategory(Intent.CATEGORY_HOME);
}
ActivityInfo aInfo =
intent.resolveActivityInfo(mContext.getPackageManager(),
STOCK_PM_FLAGS);
if (aInfo != null) {
intent.setComponent(new ComponentName(
aInfo.applicationInfo.packageName, aInfo.name));
// Don't do this if the home app is currently being
// instrumented.
ProcessRecord app = getProcessRecordLocked(aInfo.processName,
aInfo.applicationInfo.uid);
if (app == null || app.instrumentationClass == null) {
intent.setFlags(intent.getFlags() | Intent.FLAG_ACTIVITY_NEW_TASK);
mMainStack.startActivityLocked(null, intent, null, null, 0, aInfo,
null, null, 0, 0, 0, false, false);
}
}
return true;
}
......
}

public final class ActivityManagerService extends ActivityManagerNative implements Watchdog.Monitor, BatteryStatsImpl.BatteryCallback { ...... boolean startHomeActivityLocked() { ...... Intent intent = new Intent( mTopAction, mTopData != null ? Uri.parse(mTopData) : null); intent.setComponent(mTopComponent); if (mFactoryTest != SystemServer.FACTORY_TEST_LOW_LEVEL) { intent.addCategory(Intent.CATEGORY_HOME); } ActivityInfo aInfo = intent.resolveActivityInfo(mContext.getPackageManager(), STOCK_PM_FLAGS); if (aInfo != null) { intent.setComponent(new ComponentName( aInfo.applicationInfo.packageName, aInfo.name)); // Don't do this if the home app is currently being // instrumented. ProcessRecord app = getProcessRecordLocked(aInfo.processName, aInfo.applicationInfo.uid); if (app == null || app.instrumentationClass == null) { intent.setFlags(intent.getFlags() | Intent.FLAG_ACTIVITY_NEW_TASK); mMainStack.startActivityLocked(null, intent, null, null, 0, aInfo, null, null, 0, 0, 0, false, false); } } return true; } ...... } 函数首先创建一个CATEGORY_HOME类型的Intent，然后通过Intent.resolveActivityInfo函数向PackageManagerService查询Category类型为HOME的Activity，这里我们假设只有系统自带的Launcher应用程序注册了HOME类型的Activity（见packages/apps/Launcher2/AndroidManifest.xml文件）：

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<manifest
xmlns:android="http://schemas.android.com/apk/res/android"
package="com.android.launcher"
android:sharedUserId="@string/sharedUserId"
>
......
<application
android:name="com.android.launcher2.LauncherApplication"
android:process="@string/process"
android:label="@string/application_name"
android:icon="@drawable/ic_launcher_home">
<activity
android:name="com.android.launcher2.Launcher"
android:launchMode="singleTask"
android:clearTaskOnLaunch="true"
android:stateNotNeeded="true"
android:theme="@style/Theme"
android:screenOrientation="nosensor"
android:windowSoftInputMode="stateUnspecified|adjustPan">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.HOME" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.MONKEY"/>
intent-filter>
activity>
......
application>
manifest>

...... ......

因此，这里就返回com.android.launcher2.Launcher这个Activity了。由于是第一次启动这个Activity，接下来调用函数getProcessRecordLocked返回来的ProcessRecord值为null，于是，就调用mMainStack.startActivityLocked函数启动com.android.launcher2.Launcher这个Activity了，这里的mMainStack是一个ActivityStack类型的成员变量。

Step 13. ActivityStack.startActivityLocked

这个函数定义在frameworks/base/services/java/com/android/server/am/ActivityStack.java文件中

Step 14. Launcher.onCreate

这个函数定义在packages/apps/Launcher2/src/com/android/launcher2/Launcher.java文件中：

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public final class Launcher extends Activity
implements View.OnClickListener, OnLongClickListener, LauncherModel.Callbacks, AllAppsView.Watcher {
......
@Override
protected void onCreate(Bundle savedInstanceState) {
......
if (!mRestoring) {
mModel.startLoader(this, true);
}
......
}
......
}

public final class Launcher extends Activity implements View.OnClickListener, OnLongClickListener, LauncherModel.Callbacks, AllAppsView.Watcher { ...... @Override protected void onCreate(Bundle savedInstanceState) { ...... if (!mRestoring) { mModel.startLoader(this, true); } ...... } ...... } 这里的mModel是一个LauncherModel类型的成员变量，这里通过调用它的startLoader成员函数来执行加应用程序的操作。

Step 15. LauncherModel.startLoader

这个函数定义在packages/apps/Launcher2/src/com/android/launcher2/LauncherModel.java文件中：

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public class LauncherModel extends BroadcastReceiver {
......
public void startLoader(Context context, boolean isLaunching) {
......
synchronized (mLock) {
......
// Don't bother to start the thread if we know it's not going to do anything
if (mCallbacks != null && mCallbacks.get() != null) {
// If there is already one running, tell it to stop.
LoaderTask oldTask = mLoaderTask;
if (oldTask != null) {
if (oldTask.isLaunching()) {
// don't downgrade isLaunching if we're already running
isLaunching = true;
}
oldTask.stopLocked();
}
mLoaderTask = new LoaderTask(context, isLaunching);
sWorker.post(mLoaderTask);
}
}
}
......
}

public class LauncherModel extends BroadcastReceiver { ...... public void startLoader(Context context, boolean isLaunching) { ...... synchronized (mLock) { ...... // Don't bother to start the thread if we know it's not going to do anything if (mCallbacks != null && mCallbacks.get() != null) { // If there is already one running, tell it to stop. LoaderTask oldTask = mLoaderTask; if (oldTask != null) { if (oldTask.isLaunching()) { // don't downgrade isLaunching if we're already running isLaunching = true; } oldTask.stopLocked(); } mLoaderTask = new LoaderTask(context, isLaunching); sWorker.post(mLoaderTask); } } } ...... } 这里不是直接加载应用程序，而是把加载应用程序的操作作为一个消息来处理。这里的sWorker是一个Handler，通过它的post方式把一个消息放在消息队列中去，然后系统就会调用传进去的参数mLoaderTask的run函数来处理这个消息，这个mLoaderTask是LoaderTask类型的实例，于是，下面就会执行LoaderTask类的run函数了。

Step 16. LoaderTask.run

这个函数定义在packages/apps/Launcher2/src/com/android/launcher2/LauncherModel.java文件中：

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public class LauncherModel extends BroadcastReceiver {
......
private class LoaderTask implements Runnable {
......
public void run() {
......
keep_running: {
......
// second step
if (loadWorkspaceFirst) {
......
loadAndBindAllApps();
} else {
......
}
......
}
......
}
......
}
......
}

public class LauncherModel extends BroadcastReceiver { ...... private class LoaderTask implements Runnable { ...... public void run() { ...... keep_running: { ...... // second step if (loadWorkspaceFirst) { ...... loadAndBindAllApps(); } else { ...... } ...... } ...... } ...... } ...... } 这里调用loadAndBindAllApps成员函数来进一步操作。

Step 17. LoaderTask.loadAndBindAllApps
这个函数定义在packages/apps/Launcher2/src/com/android/launcher2/LauncherModel.java文件中：

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public class LauncherModel extends BroadcastReceiver {
......
private class LoaderTask implements Runnable {
......
private void loadAndBindAllApps() {
......
if (!mAllAppsLoaded) {
loadAllAppsByBatch();
if (mStopped) {
return;
}
mAllAppsLoaded = true;
} else {
onlyBindAllApps();
}
}
......
}
......
}

public class LauncherModel extends BroadcastReceiver { ...... private class LoaderTask implements Runnable { ...... private void loadAndBindAllApps() { ...... if (!mAllAppsLoaded) { loadAllAppsByBatch(); if (mStopped) { return; } mAllAppsLoaded = true; } else { onlyBindAllApps(); } } ...... } ...... } 由于还没有加载过应用程序，这里的mAllAppsLoaded为false，于是就继续调用loadAllAppsByBatch函数来进一步操作了。

Step 18. LoaderTask.loadAllAppsByBatch
这个函数定义在packages/apps/Launcher2/src/com/android/launcher2/LauncherModel.java文件中：

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public class LauncherModel extends BroadcastReceiver {
......
private class LoaderTask implements Runnable {
......
private void loadAllAppsByBatch() {
......
final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
final PackageManager packageManager = mContext.getPackageManager();
List apps = null;
int N = Integer.MAX_VALUE;
int startIndex;
int i=0;
int batchSize = -1;
while (i < N && !mStopped) {
if (i == 0) {
mAllAppsList.clear();
......
apps = packageManager.queryIntentActivities(mainIntent, 0);
......
N = apps.size();
......
if (mBatchSize == 0) {
batchSize = N;
} else {
batchSize = mBatchSize;
}
......
Collections.sort(apps,
new ResolveInfo.DisplayNameComparator(packageManager));
}
startIndex = i;
for (int j=0; i
// This builds the icon bitmaps.
mAllAppsList.add(new ApplicationInfo(apps.get(i), mIconCache));
i++;
}
final boolean first = i <= batchSize;
final Callbacks callbacks = tryGetCallbacks(oldCallbacks);
final ArrayList added = mAllAppsList.added;
mAllAppsList.added = new ArrayList();
mHandler.post(new Runnable() {
public void run() {
final long t = SystemClock.uptimeMillis();
if (callbacks != null) {
if (first) {
callbacks.bindAllApplications(added);
} else {
callbacks.bindAppsAdded(added);
}
......
} else {
......
}
}
});
......
}
......
}
......
}
......
}

public class LauncherModel extends BroadcastReceiver { ...... private class LoaderTask implements Runnable { ...... private void loadAllAppsByBatch() { ...... final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null); mainIntent.addCategory(Intent.CATEGORY_LAUNCHER); final PackageManager packageManager = mContext.getPackageManager(); List apps = null; int N = Integer.MAX_VALUE; int startIndex; int i=0; int batchSize = -1; while (i < N && !mStopped) { if (i == 0) { mAllAppsList.clear(); ...... apps = packageManager.queryIntentActivities(mainIntent, 0); ...... N = apps.size(); ...... if (mBatchSize == 0) { batchSize = N; } else { batchSize = mBatchSize; } ...... Collections.sort(apps, new ResolveInfo.DisplayNameComparator(packageManager)); } startIndex = i; for (int j=0; i

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final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);

final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null); mainIntent.addCategory(Intent.CATEGORY_LAUNCHER); 接着从mContext变量中获得PackageManagerService的接口：

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final PackageManager packageManager = mContext.getPackageManager();

final PackageManager packageManager = mContext.getPackageManager();

下一步就是通过这个PackageManagerService.queryIntentActivities接口来取回所有Action类型为Intent.ACTION_MAIN，并且Category类型为Intent.CATEGORY_LAUNCHER的Activity了。

我们先进入到PackageManagerService.queryIntentActivities函数中看看是如何获得这些Activity的，然后再回到这个函数中来看其余操作。

Step 19. PackageManagerService.queryIntentActivities

这个函数定义在frameworks/base/services/java/com/android/server/PackageManagerService.java文件中：

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class PackageManagerService extends IPackageManager.Stub {
......
public List queryIntentActivities(Intent intent,
String resolvedType, int flags) {
......
synchronized (mPackages) {
String pkgName = intent.getPackage();
if (pkgName == null) {
return (List)mActivities.queryIntent(intent,
resolvedType, flags);
}
......
}
......
}
......
}

class PackageManagerService extends IPackageManager.Stub { ...... public List queryIntentActivities(Intent intent, String resolvedType, int flags) { ...... synchronized (mPackages) { String pkgName = intent.getPackage(); if (pkgName == null) { return (List)mActivities.queryIntent(intent, resolvedType, flags); } ...... } ...... } ...... }

系统在启动PackageManagerService时，会把系统中的应用程序都解析一遍，然后把解析得到的Activity都保存在mActivities变量中，这里通过这个mActivities变量的queryIntent函数返回符合条件intent的Activity，这里要返回的便是Action类型为Intent.ACTION_MAIN，并且Category类型为Intent.CATEGORY_LAUNCHER的Activity了。

回到Step 18中的 LoaderTask.loadAllAppsByBatch函数中，从queryIntentActivities函数调用处返回所要求的Activity后，便调用函数tryGetCallbacks(oldCallbacks)得到一个返CallBack接口，这个接口是由Launcher类实现的，接着调用这个接口的.bindAllApplications函数来进一步操作。注意，这里又是通过消息来处理加载应用程序的操作的。

Step 20. Launcher.bindAllApplications

这个函数定义在packages/apps/Launcher2/src/com/android/launcher2/Launcher.java文件中：

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public final class Launcher extends Activity
implements View.OnClickListener, OnLongClickListener, LauncherModel.Callbacks, AllAppsView.Watcher {
......
private AllAppsView mAllAppsGrid;
......
public void bindAllApplications(ArrayList apps) {
mAllAppsGrid.setApps(apps);
}
......
}

public final class Launcher extends Activity implements View.OnClickListener, OnLongClickListener, LauncherModel.Callbacks, AllAppsView.Watcher { ...... private AllAppsView mAllAppsGrid; ...... public void bindAllApplications(ArrayList apps) { mAllAppsGrid.setApps(apps); } ...... } 这里的mAllAppsGrid是一个AllAppsView类型的变量，它的实际类型一般就是AllApps2D了。

Step 21. AllApps2D.setApps

这个函数定义在packages/apps/Launcher2/src/com/android/launcher2/AllApps2D.java文件中：

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public class AllApps2D
extends RelativeLayout
implements AllAppsView,
AdapterView.OnItemClickListener,
AdapterView.OnItemLongClickListener,
View.OnKeyListener,
DragSource {
......
public void setApps(ArrayList list) {
mAllAppsList.clear();
addApps(list);
}
public void addApps(ArrayList list) {
final int N = list.size();
for (int i=0; i
final ApplicationInfo item = list.get(i);
int index = Collections.binarySearch(mAllAppsList, item,
LauncherModel.APP_NAME_COMPARATOR);
if (index < 0) {
index = -(index+1);
}
mAllAppsList.add(index, item);
}
mAppsAdapter.notifyDataSetChanged();
}
......
}

public class AllApps2D extends RelativeLayout implements AllAppsView, AdapterView.OnItemClickListener, AdapterView.OnItemLongClickListener, View.OnKeyListener, DragSource { ...... public void setApps(ArrayList list) { mAllAppsList.clear(); addApps(list); } public void addApps(ArrayList list) { final int N = list.size(); for (int i=0; i

到了这里，系统默认的Home应用程序Launcher就把PackageManagerService中的应用程序加载进来了，当我们在屏幕上点击下面这个图标时，就会把刚才加载好的应用程序以图标的形式展示出来了：

点击这个按钮时，便会响应Launcher.onClick函数：

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public final class Launcher extends Activity
implements View.OnClickListener, OnLongClickListener, LauncherModel.Callbacks, AllAppsView.Watcher {
......
public void onClick(View v) {
Object tag = v.getTag();
if (tag instanceof ShortcutInfo) {
......
} else if (tag instanceof FolderInfo) {
......
} else if (v == mHandleView) {
if (isAllAppsVisible()) {
......
} else {
showAllApps(true);
}
}
}
......
}

public final class Launcher extends Activity implements View.OnClickListener, OnLongClickListener, LauncherModel.Callbacks, AllAppsView.Watcher { ...... public void onClick(View v) { Object tag = v.getTag(); if (tag instanceof ShortcutInfo) { ...... } else if (tag instanceof FolderInfo) { ...... } else if (v == mHandleView) { if (isAllAppsVisible()) { ...... } else { showAllApps(true); } } } ...... } 接着就会调用showAllApps函数显示应用程序图标：

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public final class Launcher extends Activity
implements View.OnClickListener, OnLongClickListener, LauncherModel.Callbacks, AllAppsView.Watcher {
......
void showAllApps(boolean animated) {
mAllAppsGrid.zoom(1.0f, animated);
((View) mAllAppsGrid).setFocusable(true);
((View) mAllAppsGrid).requestFocus();
// TODO: fade these two too
mDeleteZone.setVisibility(View.GONE);
}
......
}

public final class Launcher extends Activity implements View.OnClickListener, OnLongClickListener, LauncherModel.Callbacks, AllAppsView.Watcher { ...... void showAllApps(boolean animated) { mAllAppsGrid.zoom(1.0f, animated); ((View) mAllAppsGrid).setFocusable(true); ((View) mAllAppsGrid).requestFocus(); // TODO: fade these two too mDeleteZone.setVisibility(View.GONE); } ...... } 这样我们就可以看到系统中的应用程序了：

当点击上面的这些应用程序图标时，便会响应AllApps2D.onItemClick函数：

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public class AllApps2D
extends RelativeLayout
implements AllAppsView,
AdapterView.OnItemClickListener,
AdapterView.OnItemLongClickListener,
View.OnKeyListener,
DragSource {
......
public void onItemClick(AdapterView parent, View v, int position, long id) {
ApplicationInfo app = (ApplicationInfo) parent.getItemAtPosition(position);
mLauncher.startActivitySafely(app.intent, app);
}
......
}

public class AllApps2D extends RelativeLayout implements AllAppsView, AdapterView.OnItemClickListener, AdapterView.OnItemLongClickListener, View.OnKeyListener, DragSource { ...... public void onItemClick(AdapterView parent, View v, int position, long id) { ApplicationInfo app = (ApplicationInfo) parent.getItemAtPosition(position); mLauncher.startActivitySafely(app.intent, app); } ...... } 这里的成员变量mLauncher的类型为Launcher，于是就调用Launcher.startActivitySafely函数来启动应用程序了。

七 Launcher widget添加过程

Android中的AppWidget与google widget和中移动的widget并不是一个概念，这里的AppWidget只是把一个进程的控件嵌入到别外一个进程的窗口里的一种方法。View在另外一个进程里显示，但事件的处理方法还是在原来的进程里。这有点像 X Window中的嵌入式窗口。

首先我们需要了解RemoteViews, AppWidgetHost, AppWidgetHostView等概念

RemoteViews：并不是一个真正的View，它没有实现View的接口，而只是一个用于描述View的实体。比如：创建View需要的资源ID和各个控件的事件响应方法。RemoteViews会通过进程间通信机制传递给AppWidgetHost。

AppWidgetHost

AppWidgetHost是真正容纳AppWidget的地方，它的主要功能有两个：

o 监听来自AppWidgetService的事件：

class Callbacks extends IAppWidgetHost.Stub { public void updateAppWidget(int appWidgetId,RemoteViews views) { Message msg = mHandler.obtainMessage(HANDLE_UPDATE); msg.arg1 = appWidgetId;msg.obj = views; msg.sendToTarget(); }   public void providerChanged(int appWidgetId,AppWidgetProviderInfo info) { Message msg = mHandler.obtainMessage(HANDLE_PROVIDER_CHANGED);msg.arg1 = appWidgetId; msg.obj = info; msg.sendToTarget(); } }

这是主要处理update和provider_changed两个事件,根据这两个事件更新widget。

class UpdateHandler extends Handler { public UpdateHandler(Looper looper) { super(looper); }   public void handleMessage(Message msg) { switch (msg.what) { case HANDLE_UPDATE: {updateAppWidgetView(msg.arg1, (RemoteViews)msg.obj); break; } case HANDLE_PROVIDER_CHANGED: {onProviderChanged(msg.arg1, (AppWidgetProviderInfo)msg.obj); break; } } } }

o 另外一个功能就是创建AppWidgetHostView。前面我们说过RemoteViews不是真正的View，只是View的描述，而AppWidgetHostView才是真正的View。这里先创建AppWidgetHostView，然后通过AppWidgetService查询appWidgetId对应的RemoteViews，最后把RemoteViews传递给AppWidgetHostView去updateAppWidget。

public final AppWidgetHostView createView(Context context, int appWidgetId, AppWidgetProviderInfo appWidget) { AppWidgetHostView view = onCreateView(context, appWidgetId, appWidget);view.setAppWidget(appWidgetId, appWidget); synchronized (mViews) { mViews.put(appWidgetId, view); }RemoteViews views = null; try { views = sService.getAppWidgetViews(appWidgetId); } catch(RemoteException e) { throw new RuntimeException("system server dead?", e); }view.updateAppWidget(views); return view; }

AppWidgetHostView

AppWidgetHostView是真正的View，但它只是一个容器，用来容纳实际的AppWidget的View。这个AppWidget的View是根据RemoteViews的描述来创建。这是在updateAppWidget里做的：

public void updateAppWidget(RemoteViews remoteViews) { ... if (content == null && layoutId ==mLayoutId) { try { remoteViews.reapply(mContext, mView); content = mView; recycled = true; if(LOGD) Log.d(TAG, "was able to recycled existing layout"); } catch (RuntimeException e) { exception= e; } }   // Try normal RemoteView inflation if (content == null) { try { content =remoteViews.apply(mContext, this); if (LOGD) Log.d(TAG, "had to inflate new layout"); } catch(RuntimeException e) { exception = e; } } ... if (!recycled) { prepareView(content);addView(content); }   if (mView != content) { removeView(mView); mView = content; } ... }

remoteViews.apply创建了实际的View，下面代码可以看出:

public View apply(Context context, ViewGroup parent) { View result = null;   Context c =prepareContext(context);   Resources r = c.getResources(); LayoutInflater inflater =(LayoutInflater) c .getSystemService(Context.LAYOUT_INFLATER_SERVICE);   inflater =inflater.cloneInContext(c); inflater.setFilter(this);   result = inflater.inflate(mLayoutId,parent, false);   performApply(result);   return result; }

Host的实现者

AppWidgetHost和AppWidgetHostView是在框架中定义的两个基类。应用程序可以利用这两个类来实现自己的Host。Launcher是缺省的桌面，它是一个Host的实现者。

LauncherAppWidgetHostView扩展了AppWidgetHostView，实现了对长按事件的处理。

LauncherAppWidgetHost扩展了AppWidgetHost，这里只是重载了onCreateView，创建LauncherAppWidgetHostView的实例。

AppWidgetService

AppWidgetService存在的目的主要是解开AppWidgetProvider和AppWidgetHost之间的耦合。如果AppWidgetProvider和AppWidgetHost的关系固定死了，AppWidget就无法在任意进程里显示了。而有了AppWidgetService，AppWidgetProvider根本不需要知道自己的AppWidget在哪里显示了。

LauncherAppWidgetHostView: 扩展了AppWidgetHostView，实现了对长按事件的处理

LauncherAppWidgetHost: 扩展了AppWidgetHost，这里只是重载了onCreateView，创建LauncherAppWidgetHostView的实例

24 /** 25 * Specific {@link AppWidgetHost} that creates our {@link LauncherAppWidgetHostView} 26 * which correctly captures all long-press events. This ensures that users can 27 * always pick up and move widgets. 28 */ 29 public class LauncherAppWidgetHost extends AppWidgetHost { 30 public LauncherAppWidgetHost(Context context, int hostId) { 31 super(context, hostId); 32 } 33 34 @Override 35 protected AppWidgetHostView onCreateView(Context context, int appWidgetId, 36 AppWidgetProviderInfo appWidget) { 37 return new LauncherAppWidgetHostView(context); 38 } 39 }

首先在Launcher.java中定义了如下两个变量

174 private AppWidgetManager mAppWidgetManager; 175 private LauncherAppWidgetHost mAppWidgetHost;

在onCreate函数中初始化，

224 mAppWidgetManager = AppWidgetManager.getInstance(this); 225 mAppWidgetHost = new LauncherAppWidgetHost(this, APPWIDGET_HOST_ID); 226 mAppWidgetHost.startListening(); 上述代码，获取mAppWidgetManager的实例，并创建LauncherAppWidgetHost，以及监听 AppWidgetManager只是应用程序与底层Service之间的一个桥梁，是Android中标准的aidl实现方式应用程序通过AppWidgetManager调用Service中的方法 frameworks/base / core / java / android / appwidget / AppWidgetManager.java 35 /** 36 * Updates AppWidget state; gets information about installed AppWidget providers and other 37 * AppWidget related state. 38 */ 39 public class AppWidgetManager { 197 static WeakHashMap sManagerCache = new WeakHashMap(); 198 static IAppWidgetService sService; 204 /** 205 * Get the AppWidgetManager instance to use for the supplied {@link android.content.Context 206 * Context} object. 207 */ 208 public static AppWidgetManager getInstance(Context context) { 209 synchronized (sManagerCache) { 210 if (sService == null) { 211 IBinder b = ServiceManager.getService(Context.APPWIDGET_SERVICE); 212 sService = IAppWidgetService.Stub.asInterface(b); 213 } 214 215 WeakReference ref = sManagerCache.get(context); 216 AppWidgetManager result = null; 217 if (ref != null) { 218 result = ref.get(); 219 } 220 if (result == null) { 221 result = new AppWidgetManager(context); 222 sManagerCache.put(context, new WeakReference(result)); 223 } 224 return result; 225 } 226 } 227 228 private AppWidgetManager(Context context) { 229 mContext = context; 230 mDisplayMetrics = context.getResources().getDisplayMetrics(); 231 }

以上代码是设计模式中标准的单例模式

frameworks/base/ core / java / android / appwidget / AppWidgetHost.java

90 public AppWidgetHost(Context context, int hostId) { 91 mContext = context; 92 mHostId = hostId; 93 mHandler = new UpdateHandler(context.getMainLooper()); 94 synchronized (sServiceLock) { 95 if (sService == null) { 96 IBinder b = ServiceManager.getService(Context.APPWIDGET_SERVICE); 97 sService = IAppWidgetService.Stub.asInterface(b); 98 } 99 } 100 }

可以看到AppWidgetHost有自己的HostId，Handler，和sService

93 mHandler = new UpdateHandler(context.getMainLooper());

这是啥用法呢？

参数为Looper，即消息处理放到此Looper的MessageQueue中，有哪些消息呢？

40 static final int HANDLE_UPDATE = 1; 41 static final int HANDLE_PROVIDER_CHANGED = 2; 48 49 class Callbacks extends IAppWidgetHost.Stub { 50 public void updateAppWidget(int appWidgetId, RemoteViews views) { 51 Message msg = mHandler.obtainMessage(HANDLE_UPDATE); 52 msg.arg1 = appWidgetId; 53 msg.obj = views; 54 msg.sendToTarget(); 55 } 56 57 public void providerChanged(int appWidgetId, AppWidgetProviderInfo info) { 58 Message msg = mHandler.obtainMessage(HANDLE_PROVIDER_CHANGED); 59 msg.arg1 = appWidgetId; 60 msg.obj = info; 61 msg.sendToTarget(); 62 } 63 } 64 65 class UpdateHandler extends Handler { 66 public UpdateHandler(Looper looper) { 67 super(looper); 68 } 69 70 public void handleMessage(Message msg) { 71 switch (msg.what) { 72 case HANDLE_UPDATE: { 73 updateAppWidgetView(msg.arg1, (RemoteViews)msg.obj); 74 break; 75 } 76 case HANDLE_PROVIDER_CHANGED: { 77 onProviderChanged(msg.arg1, (AppWidgetProviderInfo)msg.obj); 78 break; 79 } 80 } 81 } 82 }

通过以上可以看到主要有两中类型的消息，HANDLE_UPDATE和HANDLE_PROVIDER_CHANGED

处理即通过自身定义的方法

231 /** 232 * Called when the AppWidget provider for a AppWidget has been upgraded to a new apk. 233 */ 234 protected void onProviderChanged(int appWidgetId, AppWidgetProviderInfo appWidget) { 235 AppWidgetHostView v; 236 synchronized (mViews) { 237 v = mViews.get(appWidgetId); 238 } 239 if (v != null) { 240 v.updateAppWidget(null, AppWidgetHostView.UPDATE_FLAGS_RESET); 241 } 242 } 243 244 void updateAppWidgetView(int appWidgetId, RemoteViews views) { 245 AppWidgetHostView v; 246 synchronized (mViews) { 247 v = mViews.get(appWidgetId); 248 } 249 if (v != null) { 250 v.updateAppWidget(views, 0); 251 } 252 }

那么此消息是何时由谁发送的呢？

从以上的代码中看到AppWidgetHost定义了内部类Callback，扩展了类IAppWidgetHost.Stub，类Callback中负责发送以上消息

Launcher中会调用本类中的如下方法，

102 /** 103 * Start receiving onAppWidgetChanged calls for your AppWidgets. Call this when your activity 104 * becomes visible, i.e. from onStart() in your Activity. 105 */ 106 public void startListening() { 107 int[] updatedIds; 108 ArrayList updatedViews = new ArrayList(); 109 110 try { 111 if (mPackageName == null) { 112 mPackageName = mContext.getPackageName(); 113 } 114 updatedIds = sService.startListening(mCallbacks, mPackageName, mHostId, updatedViews); 115 } 116 catch (RemoteException e) { 117 throw new RuntimeException("system server dead?", e); 118 } 119 120 final int N = updatedIds.length; 121 for (int i=0; i updateAppWidgetView(updatedIds[i], updatedViews.get(i)); 123 } 124 } 最终调用AppWidgetService中的方法startListening方法，并把mCallbacks传过去，由Service负责发送消息 Launcher中添加Widget 在Launcher中添加widget，有两种途径，通过Menu或者长按桌面的空白区域，都会弹出Dialog，让用户选择添加如下代码是当用户选择 1999 /** 2000 * Handle the action clicked in the "Add to home" dialog. 2001 */ 2002 public void onClick(DialogInterface dialog, int which) { 2003 Resources res = getResources(); 2004 cleanup(); 2005 2006 switch (which) { 2007 case AddAdapter.ITEM_SHORTCUT: { 2008 // Insert extra item to handle picking application 2009 pickShortcut(); 2010 break; 2011 } 2012 2013 case AddAdapter.ITEM_APPWIDGET: { 2014 int appWidgetId = Launcher.this.mAppWidgetHost.allocateAppWidgetId(); 2015 2016 Intent pickIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_PICK); 2017 pickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId); 2018 // start the pick activity 2019 startActivityForResult(pickIntent, REQUEST_PICK_APPWIDGET); 2020 break; 2021 }

当用户在Dialog中选择AddAdapter.ITEM_APPWIDGET时，首先会通过AppWidgethost分配一个appWidgetId，并最终调到AppWidgetService中去

同时发送Intent，其中保存有刚刚分配的appWidgetId，AppWidgetManager.EXTRA_APPWIDGET_ID

139 /** 140 * Get a appWidgetId for a host in the calling process. 141 * 142 * @return a appWidgetId 143 */ 144 public int allocateAppWidgetId() { 145 try { 146 if (mPackageName == null) { 147 mPackageName = mContext.getPackageName(); 148 } 149 return sService.allocateAppWidgetId(mPackageName, mHostId); 150 } 151 catch (RemoteException e) { 152 throw new RuntimeException("system server dead?", e); 153 } 154 } 2016 Intent pickIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_PICK); 2017 pickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId); 2018 // start the pick activity 2019 startActivityForResult(pickIntent, REQUEST_PICK_APPWIDGET); 这段代码之后，代码将会怎么执行呢，根据Log信息，可以看到代码将会执行到Setting应用中 packages/apps/Settings/ src / com / android / settings / AppWidgetPickActivity.java 此类将会通过AppWidgetService获取到当前系统已经安装的Widget，并显示出来 78 /** 79 * Create list entries for any custom widgets requested through 80 * {@link AppWidgetManager#EXTRA_CUSTOM_INFO}. 81 */ 82 void putCustomAppWidgets(List items) { 83 final Bundle extras = getIntent().getExtras(); 84 85 // get and validate the extras they gave us 86 ArrayList customInfo = null; 87 ArrayList customExtras = null; 88 try_custom_items: { 89 customInfo = extras.getParcelableArrayList(AppWidgetManager.EXTRA_CUSTOM_INFO); 90 if (customInfo == null || customInfo.size() == 0) { 91 Log.i(TAG, "EXTRA_CUSTOM_INFO not present."); 92 break try_custom_items; 93 } 94 95 int customInfoSize = customInfo.size(); 96 for (int i=0; i Parcelable p = customInfo.get(i); 98 if (p == null || !(p instanceof AppWidgetProviderInfo)) { 99 customInfo = null; 100 Log.e(TAG, "error using EXTRA_CUSTOM_INFO index=" + i); 101 break try_custom_items; 102 } 103 } 104 105 customExtras = extras.getParcelableArrayList(AppWidgetManager.EXTRA_CUSTOM_EXTRAS); 106 if (customExtras == null) { 107 customInfo = null; 108 Log.e(TAG, "EXTRA_CUSTOM_INFO without EXTRA_CUSTOM_EXTRAS"); 109 break try_custom_items; 110 } 111 112 int customExtrasSize = customExtras.size(); 113 if (customInfoSize != customExtrasSize) { 114 Log.e(TAG, "list size mismatch: EXTRA_CUSTOM_INFO: " + customInfoSize 115 + " EXTRA_CUSTOM_EXTRAS: " + customExtrasSize); 116 break try_custom_items; 117 } 118 119 120 for (int i=0; i Parcelable p = customExtras.get(i); 122 if (p == null || !(p instanceof Bundle)) { 123 customInfo = null; 124 customExtras = null; 125 Log.e(TAG, "error using EXTRA_CUSTOM_EXTRAS index=" + i); 126 break try_custom_items; 127 } 128 } 129 } 130 131 if (LOGD) Log.d(TAG, "Using " + customInfo.size() + " custom items"); 132 putAppWidgetItems(customInfo, customExtras, items); 133 } 从上述代码中可以看到，可以放置用户自己定义的伪Widget 关于伪widget，个人有如下想法：早期Android版本中的Google Search Bar就属于伪Widget，其实就是把widget做到Launcher中，但是用户体验与真widget并没有区别，个人猜想HTC的sense就是这样实现的。优点：是不需要进程间的通信，效率将会更高，并且也可以规避点Widget开发的种种限制缺点：导致Launcher代码庞大，不易于维护用户选择完之后，代码如下 135 /** 136 * {@inheritDoc} 137 */ 138 @Override 139 public void onClick(DialogInterface dialog, int which) { 140 Intent intent = getIntentForPosition(which); 141 142 int result; 143 if (intent.getExtras() != null) { 144 // If there are any extras, it's because this entry is custom. 145 // Don't try to bind it, just pass it back to the app. 146 setResultData(RESULT_OK, intent); 147 } else { 148 try { 149 mAppWidgetManager.bindAppWidgetId(mAppWidgetId, intent.getComponent()); 150 result = RESULT_OK; 151 } catch (IllegalArgumentException e) { 152 // This is thrown if they're already bound, or otherwise somehow 153 // bogus. Set the result to canceled, and exit. The app *should* 154 // clean up at this point. We could pass the error along, but 155 // it's not clear that that's useful -- the widget will simply not 156 // appear. 157 result = RESULT_CANCELED; 158 } 159 setResultData(result, null); 160 } 161 finish(); 162 } 将会 149 mAppWidgetManager.bindAppWidgetId(mAppWidgetId, intent.getComponent()); 如果此次添加的Widget是intent.getComponent()的第一个实例，将会发送如下广播 171 /** 172 * Sent when an instance of an AppWidget is added to a host for the first time. 173 * This broadcast is sent at boot time if there is a AppWidgetHost installed with 174 * an instance for this provider. 175 * 176 * @see AppWidgetProvider#onEnabled AppWidgetProvider.onEnabled(Context context) 177 */ 178 public static final String ACTION_APPWIDGET_ENABLED = "android.appwidget.action.APPWIDGET_ENABLED"; 紧接着会发送UPDATE广播 135 /** 136 * Sent when it is time to update your AppWidget. 137 * 138 *

This may be sent in response to a new instance for this AppWidget provider having 139 * been instantiated, the requested {@link AppWidgetProviderInfo#updatePeriodMillis update interval} 140 * having lapsed, or the system booting. 141 * 142 *

143 * The intent will contain the following extras: 144 *

145 * 146 * 147 * 150 * 151 *

{@link #EXTRA_APPWIDGET_IDS}

The appWidgetIds to update. This may be all of the AppWidgets created for this 148 * provider, or just a subset. The system tries to send updates for as few AppWidget 149 * instances as possible.

152 * 153 * @see AppWidgetProvider#onUpdate AppWidgetProvider.onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) 154 */ 155 public static final String ACTION_APPWIDGET_UPDATE = "android.appwidget.action.APPWIDGET_UPDATE";

待用户选择完要添加的widget之后，将会回到Launcher.java中的函数onActivityResult中

538 case REQUEST_PICK_APPWIDGET: 539 addAppWidget(data); 540 break;

上述addAppWidget中做了哪些事情呢？

1174 void addAppWidget(Intent data) { 1175 // TODO: catch bad widget exception when sent 1176 int appWidgetId = data.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, -1); 1177 AppWidgetProviderInfo appWidget = mAppWidgetManager.getAppWidgetInfo(appWidgetId); 1178 1179 if (appWidget.configure != null) { 1180 // Launch over to configure widget, if needed 1181 Intent intent = new Intent(AppWidgetManager.ACTION_APPWIDGET_CONFIGURE); 1182 intent.setComponent(appWidget.configure); 1183 intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId); 1184 1185 startActivityForResultSafely(intent, REQUEST_CREATE_APPWIDGET); 1186 } else { 1187 // Otherwise just add it 1188 onActivityResult(REQUEST_CREATE_APPWIDGET, Activity.RESULT_OK, data); 1189 } 1190 }

首先获取appWidgetId，再通过AppWidgetManager获取AppWidgetProviderInfo，最后判断此Widget是否存在ConfigActivity，如果存在则启动ConfigActivity，否则直接调用函数onActivityResult

541 case REQUEST_CREATE_APPWIDGET: 542 completeAddAppWidget(data, mAddItemCellInfo); 543 break;

通过函数completeAddAppWidget把此widget的信息插入到数据库中，并添加到桌面上

873 /** 874 * Add a widget to the workspace. 875 * 876 * @param data The intent describing the appWidgetId. 877 * @param cellInfo The position on screen where to create the widget. 878 */ 879 private void completeAddAppWidget(Intent data, CellLayout.CellInfo cellInfo) { 880 Bundle extras = data.getExtras(); 881 int appWidgetId = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, -1); 882 883 if (LOGD) Log.d(TAG, "dumping extras content=" + extras.toString()); 884 885 AppWidgetProviderInfo appWidgetInfo = mAppWidgetManager.getAppWidgetInfo(appWidgetId); 886 887 // Calculate the grid spans needed to fit this widget 888 CellLayout layout = (CellLayout) mWorkspace.getChildAt(cellInfo.screen); 889 int[] spans = layout.rectToCell(appWidgetInfo.minWidth, appWidgetInfo.minHeight); 890 891 // Try finding open space on Launcher screen 892 final int[] xy = mCellCoordinates; 893 if (!findSlot(cellInfo, xy, spans[0], spans[1])) { 894 if (appWidgetId != -1) mAppWidgetHost.deleteAppWidgetId(appWidgetId); 895 return; 896 } 897 898 // Build Launcher-specific widget info and save to database 899 LauncherAppWidgetInfo launcherInfo = new LauncherAppWidgetInfo(appWidgetId); 900 launcherInfo.spanX = spans[0]; 901 launcherInfo.spanY = spans[1]; 902 903 LauncherModel.addItemToDatabase(this, launcherInfo, 904 LauncherSettings.Favorites.CONTAINER_DESKTOP, 905 mWorkspace.getCurrentScreen(), xy[0], xy[1], false); 906 907 if (!mRestoring) { 908 mDesktopItems.add(launcherInfo); 909 910 // Perform actual inflation because we're live 911 launcherInfo.hostView = mAppWidgetHost.createView(this, appWidgetId, appWidgetInfo); 912 913 launcherInfo.hostView.setAppWidget(appWidgetId, appWidgetInfo); 914 launcherInfo.hostView.setTag(launcherInfo); 915 916 mWorkspace.addInCurrentScreen(launcherInfo.hostView, xy[0], xy[1], 917 launcherInfo.spanX, launcherInfo.spanY, isWorkspaceLocked()); 918 } 919 }

Launcher中删除widget

长按一个widget，并拖入到DeleteZone中可实现删除

具体代码在DeleteZone中

92 public void onDrop(DragSource source, int x, int y, int xOffset, int yOffset, 93 DragView dragView, Object dragInfo) { 94 final ItemInfo item = (ItemInfo) dragInfo; 95 96 if (item.container == -1) return; 97 98 if (item.container == LauncherSettings.Favorites.CONTAINER_DESKTOP) { 99 if (item instanceof LauncherAppWidgetInfo) { 100 mLauncher.removeAppWidget((LauncherAppWidgetInfo) item); 101 } 102 } else { 103 if (source instanceof UserFolder) { 104 final UserFolder userFolder = (UserFolder) source; 105 final UserFolderInfo userFolderInfo = (UserFolderInfo) userFolder.getInfo(); 106 // Item must be a ShortcutInfo otherwise it couldn't have been in the folder 107 // in the first place. 108 userFolderInfo.remove((ShortcutInfo)item); 109 } 110 } 111 if (item instanceof UserFolderInfo) { 112 final UserFolderInfo userFolderInfo = (UserFolderInfo)item; 113 LauncherModel.deleteUserFolderContentsFromDatabase(mLauncher, userFolderInfo); 114 mLauncher.removeFolder(userFolderInfo); 115 } else if (item instanceof LauncherAppWidgetInfo) { 116 final LauncherAppWidgetInfo launcherAppWidgetInfo = (LauncherAppWidgetInfo) item; 117 final LauncherAppWidgetHost appWidgetHost = mLauncher.getAppWidgetHost(); 118 if (appWidgetHost != null) { 119 appWidgetHost.deleteAppWidgetId(launcherAppWidgetInfo.appWidgetId); 120 } 121 } 122 LauncherModel.deleteItemFromDatabase(mLauncher, item); 123 }

删除时，判断删除的类型是否是AppWidget，如果是的话，要通过AppWidgetHost，删除AppWidetId，并最终从数据库中删除。

八 Launcher celllayout介绍

（1）大家都知道workspace是有celllayout组成

Celllayout被划分为了4行4列的表格，用Boolean类型的mOccupied二维数组来标记每个cell是否被占用。在attrs.xml中定义了shortAxisCells和longAxisCells分别存储x轴和y轴方向的cell个数。在Celllayout构造函数中初始化。

（2）内部类CellInfo为静态类，实现了ContextMenu.ContextMenuInfo接口，其对象用于存储cell的基本信息

VacantCell类用于存储空闲的cell，用到了同步机制用于管理对空闲位置的操作。所有的空cell都存储在vacantCells中。

cellX和cellY用于记录cell的位置,起始位0。如：(0,0) (0,1)，每一页从新开始编号。

clearVacantCells作用是将Vacant清空：具体是释放每个cell，将list清空。

findVacantCellsFromOccupied从存放cell的数值中找到空闲的cell。在Launcher.Java中的restoreState方法中调用。

（3) mPortrait用于标记是横屏还是竖屏，FALSE表示竖屏，默认为FALSE。

（4）修改CellLayout页面上cell的布局：

CellLayout页面上默认的cell为4X4=16个，可以通过修改配置文件来达到修改目的。

在CellLayout.Java类的CellLayout(Context context, AttributeSet attrs, int defStyle)构造方法中用变量mShortAxisCells和mLongAxisCells存储行和列。

其值是在自定义配置文件attrs.xml中定义的，并在workspace_screen.xml中赋初值的，初值都为4，即4行、4列。可以在workspace_screen.xml修改对应的值。

注意：CellLayout构造方法中从attrs.xml中获取定义是这样的：mShortAxisCells = a.getInt(R.styleable.CellLayout_shortAxisCells, 4);当workspace_screen.xml中没有给定义的变量赋值时，上面的4就起作用。

（5）Launcher(主屏/待机) App的BUG: 没有初始化定义CellLayout中屏幕方向的布尔值参数：

Launcher App：\cupcake\packages\apps\Launcher

待机画面分为多层，桌面Desktop Items在\res\layout-*\workspace_screen.xml中置：

... ...
launcher:shortAxisCells="4"
launcher:longAxisCells="4"
... ...
/>

以上表示4行4列.

再看看com.android.launcher.CellLayout ，其中有定义屏幕方向的参数：

private boolean mPortrait;

但是一直没有初始化，也就是mPortrait=false，桌面的单元格设置一直是以非竖屏（横屏）的设置定义进行初始化。

再来看看横屏和竖屏情况下的初始化不同之处，就可以看出BUG了：

boolean[][] mOccupied;//二元单元格布尔值数组
if (mPortrait) {
mOccupied = new boolean[mShortAxisCells][mLongAxisCells];
} else {
mOccupied = new boolean[mLongAxisCells][mShortAxisCells];
}

如果我们满屏显示桌面（横向和纵向的单元格数不一致），而不是默认的只显示4行4列，则mShortAxisCells = 4, mLongAxisCells = 5，数组应该初始化是：new boolean[4][5]，但是实际是按照非竖屏处理，初始化成了new boolean[5][4]，会产生数组越界异常。

可以在构造函数中，添加通过屏幕方向初始化mPortrait，代码如下：

public CellLayout(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
mPortrait = this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT;// 新增代码
... ...

好了就写这些，太累了，以后再补上其他跟Launcher有关的

补充：

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