android的广播机制简介

Android的广播

发送广播

Intent intent = new Intent("com.example.broadcastbestpractice. FORCE_OFFLINE ");
sendBroadcast(intent);

接收广播的XML

<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.broadcasttest"
android:versionCode="1"
android:versionName="1.0" >
<application
android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > ⋯⋯
<receiver android:name=".MyBroadcastReceiver"> <intent-filter android:priority="100" >
<action android:name="com.example.broadcasttest.MY_BROADCAST"/> </intent-filter>
</receiver> </application>
</manifest>

接收广播的JAVA

public class ForceOfflineReceiver extends BroadcastReceiver {
@Override
public void onReceive(final Context context, Intent intent) {
AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(context); dialogBuilder.setTitle("Warning");
dialogBuilder.setMessage("You are forced to be offline. Please try to login
again.");
dialogBuilder.setCancelable(false);
dialogBuilder.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
ActivityCollector.finishAll(); // 销毁所有活动
Intent intent = new Intent(context, LoginActivity.class); intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); context.startActivity(intent); // 重新启动LoginActivity
} });
AlertDialog alertDialog = dialogBuilder.create();
// 需要设置AlertDialog的类型,保证在广播接收器中可以正常弹出
alertDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_AL ERT);
alertDialog.show(); }
}