How to send a custom broadcast action to receivers in manifest?

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"));

See Broacast limitations in Android 8 release docs.

If you have multiple receivers, you can send broadcast to all the receivers using only custom action defined in manifest for that you need to add the following flag while sending broadcast

Note: I have used adb to test it on Android 10, you can add it in application

FLAG_RECEIVER_INCLUDE_BACKGROUND = 0x01000000

adb shell am broadcast -a MyAction -f 0x01000000

In Kotlin:

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

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);
    }