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AppWidgetProvider 桌面小部件
来源:互联网   发布日期:2015-10-03 10:40:10   浏览:2542次  

导读:看了下AppWidgetProvider的源代码。它继承自BroadcastReceiver,说明是一个广播接收者。 先上源代码:public class AppWidgetProvider extends BroadcastReceiver { public AppWidgetProvider()......

看了下AppWidgetProvider的源代码。它继承自BroadcastReceiver,说明是一个广播接收者。

先上源代码:

public class AppWidgetProvider extends BroadcastReceiver {

public AppWidgetProvider() {

}

// BEGIN_INCLUDE(onReceive)

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)

public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {

}

public void onDeleted(Context context, int[] appWidgetIds) {

}

public void onEnabled(Context context) {

}

public void onDisabled(Context context) {

}

}

源码很简单,我们可以看到,它实现了BroadcastReceiver的onReceive方法,在这个方法中通过intent的action来区分不同的接收的广播事件。

当action为AppWidgetManager.ACTION_APPWIDGET_UPDATE时,会调用onUpdate回调方法;

当action为AppWidgetManager.ACTION_APPWIDGET_DELETED时,会调用onDeleted回调方法;

当action为AppWidgetManager.ACTION_APPWIDGET_ENABLED时,会调用onEnabled回调方法;

当action为AppWidgetManager.ACTION_APPWIDGET_DISABLED时,会调用onDisabled回调方法。

那么上面四种类型的广播又是什么时候发出的呢?因此,我写了个继承AppWidgetProvider的类,测试了一下。

测试代码如下:

public class NewsWidgetProvider extends AppWidgetProvider {

private final static String TAG = "NewsWidgetProvider";

@Override

public void onDeleted(Context context, int[] appWidgetIds) {

Log.d(TAG , "onDeleted");

super.onDeleted(context, appWidgetIds);

}

@Override

public void onDisabled(Context context) {

Log.d(TAG , "onDisabled");

super.onDisabled(context);

}

@Override

public void onEnabled(Context context) {

Log.d(TAG , "onEnabled");

super.onEnabled(context);

}

@Override

public void onReceive(Context context, Intent intent) {

Log.d(TAG , "onReceive");

super.onReceive(context, intent);

}

@Override

public void onUpdate(Context context, AppWidgetManager appWidgetManager,

int[] appWidgetIds) {

Log.d(TAG , "onUpdate");

super.onUpdate(context, appWidgetManager, appWidgetIds);

for(int id : appWidgetIds)

Log.d(TAG , "appWidgetId=" + id);

}

}

实验结果为:

当第一个widget被创建出来时,执行顺序是:

当第二个相同的widget被创建出来时,执行顺序是:

当第三个相同的widget被创建出来时,执行顺序是:

删除一个widget时,执行顺序为:

删除最后一个widget时,执行顺序为:

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