廣播分為有序廣播和無序廣播

• 有序廣播
  所有與廣播中的action匹配的廣播接收者都可以收到這條廣播,但是是有先后順序的,按照廣播接收者的優(yōu)先級排序.
• 無序廣播
  所有與廣播中的action匹配的廣播接收者都可以收到這條廣播,并且是沒有先后順序的,視為同時收到

有序廣播

• sendOrderedBroadcast發(fā)送
• 可以添加最終廣播接收者,最終廣播接收者resultReceiver:不需要在清單文件中配置,這個廣播接收者只接收該條有序廣播,并且是最后一個收到該廣播,并且一定可以接收到,即便被攔截

發(fā)出廣播

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }


    public void click(View v) {
        Intent intent = new Intent();
        intent.setAction("orderlyBroadcast");

        //發(fā)送有序廣播
        //sendOrderedBroadcast(intent, null, null, null, 0, "每人發(fā)100W", null);

        //最終廣播接收者resultReceiver:不需要在清單文件中配置,這個廣播接收者只接收該條有序廣播,并且是最后一個收到該廣播,并且一定可以接收到,即便被攔截
        sendOrderedBroadcast(intent, null, new MyResultReceiver(), null, 0, "每人發(fā)100W", null);
    }

    class MyResultReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            String str = getResultData();
            System.out.println("最終結(jié)果:" + str);
        }
    }
}

接收者

• 優(yōu)先級 android:priority="300" 范圍-1000 至 1000 1000為最高
• 阻止廣播 abortBroadcast(),對于最終接收者來說,無效.

<receiver
    android:name=".LevelOneReceiver"
    android:enabled="true"
    android:exported="true">
    <intent-filter android:priority="1000">
        <action android:name="orderlyBroadcast"></action>
    </intent-filter>
</receiver>

<receiver
    android:name=".LevelTwoReceiver"
    android:enabled="true"
    android:exported="true">
    <intent-filter android:priority="600">
        <action android:name="orderlyBroadcast"></action>
    </intent-filter>
</receiver>

<receiver
    android:name=".LevelThreeReceiver"
    android:enabled="true"
    android:exported="true">
    <intent-filter android:priority="300">
        <action android:name="orderlyBroadcast"></action>
    </intent-filter>
</receiver>

public class LevelOneReceiver extends BroadcastReceiver {
    public LevelOneReceiver() {
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        String str = getResultData().toString();
        System.out.println("LEVEL ONE:" + str);

        //修改廣播內(nèi)容
        setResultData("每人發(fā)80W");
    }
}

public class LevelTwoReceiver extends BroadcastReceiver {
    public LevelTwoReceiver() {
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        String str = getResultData().toString();
        System.out.println("LEVEL TWO:" + str);
        //阻止廣播后,優(yōu)先級低的則收不到了,但最終廣播接收者一定會收到.
        abortBroadcast();
    }
}

public class LevelThreeReceiver extends BroadcastReceiver {
    public LevelThreeReceiver() {
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        String str = getResultData().toString();
        System.out.println("LEVEL THREE:" + str);
    }
}