Android中widget的应用【安卓源码解析三】

最近看widget，这个widget可以任意放到桌面上（前提是你的桌面上有足够大的空间），感觉效果很炫，widget就是一个BroadcastReceiver，它们使用XML metedata来描述widget的细节。AppWidget framework通过Broadcast intents和Widget通信，widget的更新使用RemoteViews来发送。Remote Views被包装成一个layout和特定内容来显示到桌面上。widget是继承于AppWidgetProvider类的，重写几个方法，有：onEnabled（）：程序第一次启动的时候调用。onUpdate（）：程序更新的时候用，由android:updatePeriodMillis=“1000"这个来控制的。onDeleted（）：widget被删除时候调用。onDisabled（）这个方法。还得写这个appwidget-provider布局文件。这个widget在manifest中需要注册一下receiver

在<appwidget-provider>中添加属性android:configure="com.cn.exmaple.widget.daming.ExampleAppWidgetConfigure"，指向对应的配置类。这个类可以是继承activity的类。这个程序是我修改的apidemo中的代码。感觉这个例子写的还行，就整理下，方便自己用。下面看程序截图：

长按桌面，弹出dialog，选择窗口小部件：点击大明修改api后弹出的界面：

输入文字：点击确定后，显示在桌面：

源码奉上：

在ExmapleWidgetApp工程下：

一、在com.cn.exmaple.widget.daming包下面的ExampleAppWidgetProvider.java类中的代码：

/* * Copyright (C) 2008 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package com.cn.exmaple.widget.daming;import android.appwidget.AppWidgetManager;import android.appwidget.AppWidgetProvider;import android.content.ComponentName;import android.content.Context;import android.content.pm.PackageManager;import android.os.SystemClock;import android.util.Log;import android.widget.RemoteViews;/** * A widget provider. We have a string that we pull from a preference in order to show * the configuration settings and the current time when the widget was updated. We also * register a BroadcastReceiver for time-changed and timezone-changed broadcasts, and * update then too. * * See also the following files: * <ul> * <li>ExampleAppWidgetConfigure.java</li> * <li>ExampleBroadcastReceiver.java</li> * <li>res/layout/appwidget_configure.xml</li> * <li>res/layout/appwidget_provider.xml</li> * <li>res/xml/appwidget_provider.xml</li> * </ul> */public class ExampleAppWidgetProvider extends AppWidgetProvider { // log tag private static final String TAG = "ExampleAppWidgetProvider"; @Override public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) { Log.d(TAG, "onUpdate"); // For each widget that needs an update, get the text that we should display: // - Create a RemoteViews object for it // - Set the text in the RemoteViews object // - Tell the AppWidgetManager to show that views object for the widget. final int N = appWidgetIds.length; for (int i=0; i<N; i++) { int appWidgetId = appWidgetIds[i]; String titlePrefix = ExampleAppWidgetConfigure.loadTitlePref(context, appWidgetId); updateAppWidget(context, appWidgetManager, appWidgetId, titlePrefix); } } @Override public void onDeleted(Context context, int[] appWidgetIds) { Log.d(TAG, "onDeleted"); // When the user deletes the widget, delete the preference associated with it. final int N = appWidgetIds.length; for (int i=0; i<N; i++) { ExampleAppWidgetConfigure.deleteTitlePref(context, appWidgetIds[i]); } } @Override public void onEnabled(Context context) { Log.d(TAG, "onEnabled"); // When the first widget is created, register for the TIMEZONE_CHANGED and TIME_CHANGED // broadcasts. We don't want to be listening for these if nobody has our widget active. // This setting is sticky across reboots, but that doesn't matter, because this will // be called after boot if there is a widget instance for this provider. PackageManager pm = context.getPackageManager(); pm.setComponentEnabledSetting( new ComponentName("com.cn.exmaple.widget.daming", ".ExampleBroadcastReceiver"), PackageManager.COMPONENT_ENABLED_STATE_ENABLED, PackageManager.DONT_KILL_APP); } @Override public void onDisabled(Context context) { // When the first widget is created, stop listening for the TIMEZONE_CHANGED and // TIME_CHANGED broadcasts. Log.d(TAG, "onDisabled"); PackageManager pm = context.getPackageManager(); pm.setComponentEnabledSetting( new ComponentName("com.cn.exmaple.widget.daming", ".ExampleBroadcastReceiver"), PackageManager.COMPONENT_ENABLED_STATE_ENABLED, PackageManager.DONT_KILL_APP); } static void updateAppWidget(Context context, AppWidgetManager appWidgetManager, int appWidgetId, String titlePrefix) { Log.d(TAG, "updateAppWidget appWidgetId=" + appWidgetId + " titlePrefix=" + titlePrefix); // Getting the string this way allows the string to be localized. The format // string is filled in using java.util.Formatter-style format strings. CharSequence text = context.getString(R.string.appwidget_text_format, ExampleAppWidgetConfigure.loadTitlePref(context, appWidgetId), "0x" + Long.toHexString(SystemClock.elapsedRealtime())); // Construct the RemoteViews object. It takes the package name (in our case, it's our // package, but it needs this because on the other side it's the widget host inflating // the layout from our package). RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.appwidget_provider); views.setTextViewText(R.id.appwidget_text, text); // Tell the widget manager appWidgetManager.updateAppWidget(appWidgetId, views); }}

二、在ExampleAppWidgetConfigure.java中的代码：

/* * Copyright (C) 2008 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package com.cn.exmaple.widget.daming;import java.util.ArrayList;import android.app.Activity;import android.appwidget.AppWidgetManager;import android.content.Context;import android.content.Intent;import android.content.SharedPreferences;import android.os.Bundle;import android.view.View;import android.widget.EditText;/** * The configuration screen for the ExampleAppWidgetProvider widget sample. */public class ExampleAppWidgetConfigure extends Activity { static final String TAG = "ExampleAppWidgetConfigure"; private static final String PREFS_NAME = "com.cn.exmaple.widget.daming.ExampleAppWidgetProvider"; private static final String PREF_PREFIX_KEY = "prefix_"; int mAppWidgetId = AppWidgetManager.INVALID_APPWIDGET_ID; EditText mAppWidgetPrefix; public ExampleAppWidgetConfigure() { super(); } @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); // Set the result to CANCELED. This will cause the widget host to cancel // out of the widget placement if they press the back button. setResult(RESULT_CANCELED); // Set the view layout resource to use. setContentView(R.layout.appwidget_configure); // Find the EditText mAppWidgetPrefix = (EditText)findViewById(R.id.appwidget_prefix); // Bind the action for the save button. findViewById(R.id.save_button).setOnClickListener(mOnClickListener); // Find the widget id from the intent. Intent intent = getIntent(); Bundle extras = intent.getExtras(); if (extras != null) { mAppWidgetId = extras.getInt( AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID); } // If they gave us an intent without the widget id, just bail. if (mAppWidgetId == AppWidgetManager.INVALID_APPWIDGET_ID) { finish(); } mAppWidgetPrefix.setText(loadTitlePref(ExampleAppWidgetConfigure.this, mAppWidgetId)); } View.OnClickListener mOnClickListener = new View.OnClickListener() { public void onClick(View v) { final Context context = ExampleAppWidgetConfigure.this; // When the button is clicked, save the string in our prefs and return that they // clicked OK. String titlePrefix = mAppWidgetPrefix.getText().toString(); saveTitlePref(context, mAppWidgetId, titlePrefix); // Push widget update to surface with newly set prefix AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context); ExampleAppWidgetProvider.updateAppWidget(context, appWidgetManager, mAppWidgetId, titlePrefix); // Make sure we pass back the original appWidgetId Intent resultValue = new Intent(); resultValue.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, mAppWidgetId); setResult(RESULT_OK, resultValue); finish(); } }; // Write the prefix to the SharedPreferences object for this widget static void saveTitlePref(Context context, int appWidgetId, String text) { SharedPreferences.Editor prefs = context.getSharedPreferences(PREFS_NAME, 0).edit(); prefs.putString(PREF_PREFIX_KEY + appWidgetId, text); prefs.commit(); } // Read the prefix from the SharedPreferences object for this widget. // If there is no preference saved, get the default from a resource static String loadTitlePref(Context context, int appWidgetId) { SharedPreferences prefs = context.getSharedPreferences(PREFS_NAME, 0); String prefix = prefs.getString(PREF_PREFIX_KEY + appWidgetId, null); if (prefix != null) { return prefix; } else { return context.getString(R.string.appwidget_prefix_default); } } static void deleteTitlePref(Context context, int appWidgetId) { } static void loadAllTitlePrefs(Context context, ArrayList<Integer> appWidgetIds, ArrayList<String> texts) { }}

三、在ExampleBroadcastReceiver.java中的代码：

四、在xml下的appwidget-provider的布局文件中：

五、在layout下的appwidget_provider.xml中的代码：

六、在layout下的appwidget_configure.xml中的代码：

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/appwidget_configure_instructions" /> <EditText android:id="@+id/appwidget_prefix" android:layout_width="fill_parent" android:layout_height="wrap_content" /> <Button android:id="@+id/save_button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@android:string/ok" /></LinearLayout>

七、AndroidManifest.xml中的代码：

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.cn.exmaple.widget.daming" android:versionCode="1" android:versionName="1.0"> <uses-sdk android:minSdkVersion="8" /> <application android:icon="@drawable/icon" android:label="@string/app_name"> <receiver android:name=".ExampleAppWidgetProvider"> <meta-data android:name="android.appwidget.provider" android:resource="@xml/appwidget_provider" /> <intent-filter> <action android:name="android.appwidget.action.APPWIDGET_UPDATE" /> </intent-filter> </receiver> <activity android:name=".ExampleAppWidgetConfigure"> <intent-filter> <action android:name="android.appwidget.action.APPWIDGET_CONFIGURE" /> </intent-filter> </activity> <receiver android:name=".ExampleBroadcastReceiver" android:enabled="true"> <intent-filter> <action android:name="android.intent.ACTION_TIMEZONE_CHANGED" /> <action android:name="android.intent.ACTION_TIME" /> </intent-filter> </receiver> </application></manifest>

八、在values下的string.xml中的代码：

更多相关文章

随机推荐