how to broadcast Receiver and MVVM?

Question

my manifest

Answer 1

1. define base class for LiveData of BroadcastReceiver

public class ReceiverLiveData extends LiveData {

    private final Context context;
    private final IntentFilter filter;
    private final BiFunction mapFunc;

    public ReceiverLiveData(Context context, IntentFilter filter, BiFunction mapFunc) {
        this.context = context;
        this.filter = filter;
        this.mapFunc = mapFunc;
    }

    @Override
    protected void onInactive() {
        super.onInactive();
        context.unregisterReceiver(mBroadcastReceiver);
    }

    @Override
    protected void onActive() {
        super.onActive();
        setValue(mapFunc.apply(context, new Intent()));
        context.registerReceiver(mBroadcastReceiver, filter);
    }

    private final BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            setValue(mapFunc.apply(context, intent));
        }
    };
}

2. declare your variable in ViewModel, for example battery change intent

    public static class ViewModel extends AndroidViewModel {
        public final LiveData batteryIntentLiveData = new ReceiverLiveData<>(getApplication(), new IntentFilter(Intent.ACTION_BATTERY_CHANGED), (context, intent) -> intent);
        public final LiveData activeNetworkInfoLiveData = new ReceiverLiveData<>(getApplication(), new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION), ((context, intent) -> ((ConnectivityManager) context.getSystemService(CONNECTIVITY_SERVICE)).getActiveNetworkInfo()));

        public ViewModel(@NonNull Application application) {
            super(application);
        }
    }

3. initialize ViewModel in Activity::onCreate

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActivityMainBinding binding = ActivityMainBinding.inflate(getLayoutInflater());
        binding.setViewModel(new ViewModelProvider(this).get(ViewModel.class));
        binding.setLifecycleOwner(this);
        setContentView(binding.getRoot());
    }

4. use batteryIntentLiveData & activeNetworkInfoLiveData in your DataBinding layout