android 中 AppWidget 的 ListView 的实现

http://www.cnblogs.com/debugman/archive/2012/06/18/android.html

3.0 以后系统直接支持了ListView. 关于ListView 的国内资料匮乏,大多数例子都是转来转去。由于初学android, 鄙人在搜索资料的时候遇到了不少麻烦~很是郁闷和苦恼~深感国内学习氛围确实怪异，学习方式需要改变。应该多去查看官方文档。。。。

话不多说，现在开始listView 实现：

这是文档列出的支持的布局和widget控件：

A RemoteViews object (and, consequently, an App Widget) can support the following layout classes:

FrameLayout
LinearLayout
RelativeLayout

And the following widget classes:

AnalogClock
Button
Chronometer
ImageButton
ImageView
ProgressBar
TextView
ViewFlipper
ListView
GridView
StackView
AdapterViewFlipper

Descendants of these classes are not supported

其中有ListView和 GridView 等控件。

android 中实现 appWidget 有自己的一套机制：

1. widget 的支持，AppWidgetProvider 类的实现。

覆盖在 AppWidgetProvider 的 OnReceive() 函数，从android的源码中可以知道，AppWidgetProvider 的 OnUpdate() ， OnEnable(), OnDelete() 等方法都是从 OnReceive() 方法中分配进去的。即所有的广播先通过OnReceive()函数，再分配到OnUpdate()等函数去。

public void onReceive(Context context, Intent intent) { // Protect against rogue update broadcasts (not really a security issue, // just filter bad broacasts out so subclasses are less likely to crash). String action = intent.getAction(); if (AppWidgetManager.ACTION_APPWIDGET_UPDATE.equals(action)) { Bundle extras = intent.getExtras(); if (extras != null ) { int [] appWidgetIds = extras.getIntArray(AppWidgetManager.EXTRA_APPWIDGET_IDS); if (appWidgetIds != null && appWidgetIds.length > 0 ) { this .onUpdate(context, AppWidgetManager.getInstance(context), appWidgetIds); } } } else if (AppWidgetManager.ACTION_APPWIDGET_DELETED.equals(action)) { Bundle extras = intent.getExtras(); if (extras != null && extras.containsKey(AppWidgetManager.EXTRA_APPWIDGET_ID)) { final int appWidgetId = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID); this .onDeleted(context, new int [] { appWidgetId }); } } else if (AppWidgetManager.ACTION_APPWIDGET_ENABLED.equals(action)) { this .onEnabled(context); } else if (AppWidgetManager.ACTION_APPWIDGET_DISABLED.equals(action)) { this .onDisabled(context); } } // END_INCLUDE(onReceive)

注意到：

String action = intent.getAction();

这里 intent 先获取 action, 通过action 来获取到广播并区分类型，所以自己定义 action 通过 PendingIntent 来实现各种跳转~

到这里先摆下基础的文件吧：

这里需要注意到的是：android中的xml 文件不能有大写字母。区分单词用最好用 _ 符号。否则找不到文件名。

provider_info 文件，提供 appWidget 的一些基本控制信息。

<?xml version= "1.0" encoding= "utf-8" ?>

                                            xmlns:android=           "http://schemas.android.com/apk/res/android"                                            android:minWidth =            "294dp"                                            android:minHeight =            "367dp"                                            android:updatePeriodMillis =            "1000"                                            android:initialLayout =            "@layout/listview"                                            android:background=           "#0000ff"                                            >

listview 文件： ListView 控件就在内部：

<?xml version= "1.0" encoding= "utf-8" ?>

                                            xmlns:android=           "http://schemas.android.com/apk/res/android"                                            android:layout_width=           "294dp"                                            android:layout_height=           "400dp"           >                                                                                          android:layout_width=           "fill_parent"                                              android:layout_height=           "360dp"                                              android:minHeight=           "100dp"                                              android:id=           "@+id/listviewWrapper"                                              >                                                                                                  android:layout_height =            "360dp"                                                  android:layout_width =            "294dp"                                                  android:background=           "#000000"                                                  android:id =            "@+id/myListView"                                                />                                                                                                                                      android:layout_width=           "fill_parent"                                              android:layout_height=           "wrap_content"                                              android:layout_below=           "@id/listviewWrapper"                                                                                  android:layout_alignParentLeft=           "true"                                              android:id=           "@+id/refresh"                                              android:text=           "refresh"                                              >

下面是list_item 文件：

<?xml version= "1.0" encoding= "utf-8" ?>

                                            xmlns:android=           "http://schemas.android.com/apk/res/android"                                            android:layout_width=           "match_parent"                                            android:layout_height=           "match_parent"           >                                                                                          android:layout_width=           "fill_parent"                                              android:layout_height=           "wrap_content"                                              android:gravity=           "center"                                              android:textColor=           "#ff0000"                                              android:layout_marginTop=           "5px"                                              android:layout_marginBottom=           "5px"                                              android:paddingBottom=           "25px"                                              android:paddingTop=           "5px"                                              android:textSize=           "60px"                                              android:id=           "@+id/item"                                            />                                                                                          android:id=           "@+id/imageItem"                                              android:layout_width=           "wrap_content"                                              android:layout_height=           "wrap_content"                                              android:layout_alignParentRight=           "true"                                              android:layout_alignRight=           "@id/item"                                              />

　list 的 item 中也可以添加 ImageView 等appWidget 支持的控件。

这是manifest 问件：

<?xml version= "1.0" encoding= "utf-8" ?>

           "http://schemas.android.com/apk/res/android"                                              package           =           "com.zgc.AppWidget6"                                              android:versionCode=           "1"                                              android:versionName=           "1.0"            >                                                                                         "15"            />                                                                                                                                android:icon=           "@drawable/ic_launcher"                                                  android:label=           "@string/app_name"            >                                                             ".MyWidgetProvider"           >                                                                 "android.appwidget.provider"                                                          android:resource=           "@xml/provider_info"            >                                                                                                                                                                                 "android.appwidget.action.APPWIDGET_UPDATE"           >                                                                                                                                                                                                                 ".MyWidgetService"                                                      android:permission=           "android.permission.BIND_REMOTEVIEWS"                                                      android:exported=           "false"            >                                                                                                                                                                                     "android.permission.INTERNET"           >

其中 service 提供 name 是 MyWidgetService ，他是继承RemoteViewsService 类。是我们需要为远程 ListView 提供数据源的服务。

RemoteViewsService的是个服务。其中：

public RemoteViewsFactory onGetViewFactory(Intent intent) { return new ListRemoteViewsFactory( this .getApplicationContext(), intent); }

ListRemoteViewsFactory 这里就充当 ListView 的数据源。

就好比在activity 中使用ListView 一样。也需要通过AdapterView 来为ListView 提供数据源。不过AdatperView中提供了每一Item的方法。

具体逻辑如图：

下面是 service 的源代码：

public class MyWidgetService extends RemoteViewsService { @Override public RemoteViewsFactory onGetViewFactory(Intent intent) { return new ListRemoteViewsFactory( this .getApplicationContext(), intent); } @Override public void onCreate() { // TODO Auto-generated method stub System.out.println( "service in onCreate" ); super .onCreate(); } @Override public void onDestroy() { // TODO Auto-generated method stub System.out.println( "service in onDestory" ); super .onDestroy(); } @Override public boolean onUnbind(Intent intent) { // TODO Auto-generated method stub System.out.println( "service in onUnbind" ); return super .onUnbind(intent); } @Override public void onRebind(Intent intent) { // TODO Auto-generated method stub System.out.println( "service in onRebind" ); super .onRebind(intent); } @Override public void onStart(Intent intent, int startId) { // TODO Auto-generated method stub System.out.println( "service in onStart" ); super .onStart(intent, startId); } @Override public int onStartCommand(Intent intent, int flags, int startId) { // TODO Auto-generated method stub return super .onStartCommand(intent, flags, startId); }

class ListRemoteViewsFactory implements RemoteViewsService.RemoteViewsFactory { private static int mCount = 0 ; private List mWidgetItems = new ArrayList(); private List mWidgetItemsAttr= new ArrayList(); private Context mContext; private int mAppWidgetId; private String url = "http://10.40.73.77/php/getData.php" ; public static int whichPage = 0 ; public static int mainPageId = - 1 ; public static int secPageId = - 1 ; public static final int mainPage = 0 ; public static final int secPage = 1 ; public static List checkPos = new ArrayList(); //public static int[] checkPosArr = new int[100]; public ListRemoteViewsFactory(Context context, Intent intent){ mContext = context; mAppWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID); } @Override public void onCreate() { System.out.println( "onCreate in factory" ); // TODO Auto-generated method stub try { Thread.sleep( 3000 ); } catch (InterruptedException e) { e.printStackTrace(); } } @Override public int getCount() { // TODO Auto-generated method stub if (whichPage == mainPage){ mCount = mWidgetItems.size(); } else if (whichPage == secPage){ mCount = mWidgetItemsAttr.size(); } return mCount; } @Override public long getItemId( int position) { // TODO Auto-generated method stub return position; } @Override public RemoteViews getLoadingView() { // TODO Auto-generated method stub System.out.println( "getLoadingView" ); return null ; } @Override public RemoteViews getViewAt( int position) { System.out.println( "getViewAt" ); // TODO Auto-generated method stub RemoteViews rv = new RemoteViews(mContext.getPackageName(), R.layout.list_item); switch (whichPage){ case mainPage : if (- 1 == mainPageId){ //refresh main page System.out.println( "getViewAt mainPage refresh" ); rv.setTextViewText(R.id.item, mWidgetItems.get(position).text); Bundle extras = new Bundle(); extras.putInt( "page" , 0 ); extras.putInt(MyWidgetProvider.EXTRA_ITEM, position); extras.putString( "name" , mWidgetItems.get(position).text); Intent fillInIntent = new Intent(); fillInIntent.putExtras(extras); rv.setOnClickFillInIntent(R.id.item, fillInIntent); } else { //refresh to secPage list content System.out.println( "getViewAt mainPage item click" ); mainPageId = - 1 ; } break ; case secPage: if (- 1 == secPageId){ //refresh when click back button, but I only have one home button //refresh second list page System.out.println( "getViewAt secPage refresh" ); rv.setTextViewText(R.id.item, mWidgetItemsAttr.get(position)); rv.setImageViewResource(R.id.imageItem, R.drawable.checkbox); Bundle extras = new Bundle(); extras.putInt( "page" , 1 ); extras.putInt(MyWidgetProvider.EXTRA_ITEM, position); Intent fillInIntent = new Intent(); fillInIntent.putExtras(extras); rv.setOnClickFillInIntent(R.id.item, fillInIntent); rv.setOnClickFillInIntent(R.id.imageItem, fillInIntent); } else { //change positon rv.setTextViewText(R.id.item, mWidgetItemsAttr.get(position)); if (- 1 != checkPos.indexOf(position)){ //change list item picture to be checked rv.setImageViewResource(R.id.imageItem, R.drawable.checkedbox); } else { rv.setImageViewResource(R.id.imageItem, R.drawable.checkbox); } //每一个 item 都需要从新赋值。否则会出错！！具体原因没有查明 Bundle extras = new Bundle(); extras.putInt( "page" , 1 ); extras.putInt(MyWidgetProvider.EXTRA_ITEM, position); Intent fillInIntent = new Intent(); fillInIntent.putExtras(extras); rv.setOnClickFillInIntent(R.id.item, fillInIntent); rv.setOnClickFillInIntent(R.id.imageItem, fillInIntent); } break ; default : ; } return rv; } @Override public int getViewTypeCount() { // TODO Auto-generated method stub return 1 ; } @Override public boolean hasStableIds() { // TODO Auto-generated method stub return true ; } @Override public void onDataSetChanged() { // TODO Auto-generated method stub System.out.println( "onDataSetChanged" ); //this func is get data mWidgetItems.clear(); switch (whichPage){ case mainPage : System.out.println( "onDataSetChanged_mainPage" ); if (- 1 == mainPageId){ //refresh main page try { URL reqURL = new URL(url); BufferedReader br = new BufferedReader( new InputStreamReader(reqURL.openStream(), "gbk" )); StringBuffer sb = new StringBuffer(); String line; while ( null != (line = br.readLine())){ sb.append(line); } br.close(); ArrayList > mList= new ArrayList>(); JSONArray arr_json = new JSONArray(sb.toString()); for ( int i = 0 , len = arr_json.length(); i < len; i++){ String strName = arr_json.getJSONObject(i).getString( "name" ); String strUrl = arr_json.getJSONObject(i).getString( "url" ); int id = arr_json.getJSONObject(i).getInt( "id" ); Map map = new HashMap(); mWidgetItems.add( new WidgetItem(strName, id)); map.put( "name" , strName); map.put( "url" , strUrl); mList.add(map); } mCount = mWidgetItems.size(); } catch (Exception e){ Toast.makeText(mContext, "can't connect server" , Toast.LENGTH_LONG).show(); } } else { // System.out.println( "onDataSetChanged_mainPage else" ); WidgetItem item = mWidgetItems.get(mainPageId); } System.out.println( "onDataSetChanged_-1" ); break ; case secPage: //here can get more info from server, but no need to get more infomation, if (- 1 == secPageId){ mWidgetItemsAttr.clear(); System.out.println( "onDataSetChanged_secPage -1" ); mWidgetItemsAttr.add( "zhang" ); mWidgetItemsAttr.add( "gui" ); mWidgetItemsAttr.add( "chuang" ); mWidgetItemsAttr.add( "hui" ); mWidgetItemsAttr.add( "cong" ); mWidgetItemsAttr.add( "gui" ); mWidgetItemsAttr.add( "chuang" ); mWidgetItemsAttr.add( "hui" ); mWidgetItemsAttr.add( "cong" ); mWidgetItemsAttr.add( "gui" ); mWidgetItemsAttr.add( "chuang" ); mWidgetItemsAttr.add( "hui" ); mWidgetItemsAttr.add( "cong" ); mWidgetItemsAttr.add( "cong" ); } else { System.out.println( "onDataSetChanged_secPage else" ); } break ; default : return ; } } @Override public void onDestroy() { System.out.println( "onDestory in factory" ); // TODO Auto-generated method stub mWidgetItems.clear(); } }


注意到几个方法：

public void

onDataSetChanged(){.....}

public RemoteViews getViewAt( int

position) {....}

public int

getCount() {....}

onDateSetChanged(){...} 方法在你使用的 MyWidgetProvider 的 onReceive() 和 onUpdate() 方法中调用

AppWidgetManager 的实例的方法: mgr.notifyAppWidgetViewDataChanged(appIds, R.id.myListView); 来更新要求更新数据源：
首先就会调用 ：

onDataSetChanged(){.....}

然后在调用 getViewAt( int

position){....}
其中getViewAt 的参数 position 就是你的ListView中每一项 item 的位置。从

0

计数。
其中你必须 override 的 getCount()方法是返回你的ListView item 的总数。这个自己必须返回自己的数据才能让getViewAt的postion能够计数。

你获取数据的方式比如http从服务器获取数据的话，就需要放在onDateSetChagged()方法里。
当然

public

RemoteViews getLoadingView(){...} 也可以。不过要注意放回的是RemoteViews 就说明这是要更新界面的，这个函数的作用就是在你更新界面的时候如果耗时就会显示 正在加载... 的默认字样，但是你可以更改这个界面。需要返回一个 RemoteViews 类型。其中你可以使用RemoteViews 去切换自己定义的 Layout 。

关于 remoteViews 的实例的方法：

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