How to send a custom broadcast action to receivers

问题:

MyReceiver.java

public class MyReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(final Context context, final Intent intent) {
        Log.i("MyReceiver", "MyAction received!");
    }
}

In AndroidManifest.xml (under the application tag)

<receiver android:name=".MyReceiver">
    <intent-filter>
        <action android:name="MyAction" />
    </intent-filter>
</receiver>

MainActivity.Java

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        sendBroadcast(new Intent("MyAction"));
    }
}

MyReceiver.onReceive method is never triggered. Did I miss something?

回答1:

I use Android 8.

Then you have to use an explicit Intent, one that identifies the receiver, such as:

sendBroadcast(new Intent(this, MyReceiver.class).setAction("MyAction"));

回答2:

In Android 8 onwords

• We need to provide the explicite class for handling i.e setcomponent param along with action

Example :

  private void triggerBroadCast(String firstFavApp, String secondFavApp) {
        Intent intent = new Intent("FavAppsUpdated");
        intent.addFlags(Intent.FLAG_INCLUDE_STOPPED_PACKAGES);
        intent.putExtra("FIRST_FAV_APP", firstFavApp);
        intent.putExtra("SECOND_FAV_APP", secondFavApp);
        intent.setComponent(new
                ComponentName("com.android.systemui",
                "com.android.systemui.statusbar.phone.FavAppsChanged"));

        Log.i(TAG, "Trigger Fav Apps" + firstFavApp + " " + secondFavApp);
        favouriteContract.getAppContext().sendBroadcast(intent);
    }

Below Android 8

• Only action is enough for receiving Broadcast

   void broadCastParkingStates(Context context) {
        Intent intent = new Intent("ReverseCameraStates");
        intent.addFlags(Intent.FLAG_INCLUDE_STOPPED_PACKAGES);
        intent.putExtra("PARKING_GUIDE", ReverseCameraPreference.getParkingGuide(context));
        intent.putExtra("PARKING_SENSOR", ReverseCameraPreference.getParkingSensor(context));
        intent.putExtra("TRAJECTORY", ReverseCameraPreference.getTrajectory(context));
        Log.i("BootCompletedReceiver", "Sending Reverse Camera settings states BaordCast");
        Log.i("BootCompletedReceiver", "States Parking:Sensor:Trajectory="
                + intent.getExtras().getBoolean("PARKING_GUIDE")
                + ":" + intent.getExtras().getBoolean("PARKING_SENSOR")
                + ":" + intent.getExtras().getBoolean("TRAJECTORY")
        );
        context.sendBroadcast(intent);
    }

回答3:

In Kotlin

 val intent = Intent(this, MyBroadCastReceiver::class.java)
            intent.addCategory(Intent.CATEGORY_DEFAULT)
            intent.action = "my.custom.braodacat"
            sendBroadcast(intent)

回答4:

The string itself does not matter, just need to be the same in all places and unique, I use fully qualified name of the constant.

<receiver android:name="com.mypackage.receivers.MyBroadcastReceiver">
    <intent-filter>
        <action android:name="com.mypackage.receivers.MyBroadcastReceiver.ACTION_CUSTOM"/>
    </intent-filter>
</receiver>

The receiver:

package com.mypackage.receivers;

public class MyBroadcastReceiver extends BroadcastReceiver {
    public static final String ACTION_CUSTOM = "com.mypackage.receivers.MyBroadcastReceiver.ACTION_CUSTOM";
@Override
    public void onReceive(Context context, Intent intent) {
      if (ACTION_CUSTOM.equals(intent.getAction())) {
            // do custom action
        }
    }
}

To broadcast the intent:

sendBroadcast(new Intent(MyBroadcastReceiver.ACTION_CUSTOM));