注册广播接收器的方法

Question

in the project that I got to work on there's a use of Broadcast receivers . Now, those receivers are registered in the Manifest and also there's this method:

private static void enableComponent(Context context, Class<?> component) {

    ComponentName connectionReceiverComponent = new ComponentName(context, component);
    context.getPackageManager().setComponentEnabledSetting(connectionReceiverComponent, PackageManager.COMPONENT_ENABLED_STATE_ENABLED, PackageManager.DONT_KILL_APP);
}

I'm a bit confused about it, because since Android 8 we can't register receivers in the Manifest anymore, instead we have to use runtime registration, using context.registerReceiver() , thus it is not necessary even to put the receivers in the Manifest. And yet, the registration that uses ComponentName still works on Android 8 and Android 9 . Can you please explain what's difference between those two methods, and why it works and Android 8 and beyond?

Answer 1

In Activity you can register like this.

private BroadcastReceiver receiver;

@Override
public void onCreate(Bundle savedInstanceState){

  IntentFilter filter = new IntentFilter();
  filter.addAction("SOME_ACTION"); 

  receiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
      //do something based on the intent's action
    }
  };
     registerReceiver(receiver, filter);
}

Or in your ActivityManifest

<receiver
 android:name=".ConnectivityBroadcastReceiver">
<intent-filter>
  <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
</intent-filter>
</receiver>