android - 配置 RxJava 以将数据从 GCMListenerService 发送到 Activity

Question

我正在尝试从我的 GCMServiceListener 向我的 Activity 发送更新，所以，我正在使用 RxJava/RxAndroid 并创建了一个 BusClass 用于处理发送和 Observers

public class ClientBus {

//private final PublishSubject<Object> _bus = PublishSubject.create();

// If multiple threads are going to emit events to this
// then it must be made thread-safe like this instead
private final Subject<Object, Object> _bus = new SerializedSubject<>(PublishSubject.create());

public void send(Object o) {
    _bus.onNext(o);
}

public Observable<Object> toObserverable() {
    return _bus;
}

public boolean hasObservers() {
    return _bus.hasObservers();
}
}

在我的 Application Class 中，我这样做是为了初始化 BusClass

private ClientBus clientBus;

public ClientBus getRxBusSingleton() {
    if (clientBus == null) {
        clientBus = new ClientBus();
    }
    return clientBus;
}

在我想接收消息的 Activity 中，我注册了一个 CompositeSubscription 并从 Application Class 获取了对我的 ClientBus 类 的引用

clientBus = ((MyApplication) getApplicationContext()).getRxBusSingleton();

 @Override
protected void onStart() {
    super.onStart();
    initSubscriptions();
}

@Override
protected void onStop() {
    super.onStop();
    _subscriptions.unsubscribe();
}


void initSubscriptions() {
    _subscriptions = new CompositeSubscription();
    _subscriptions.add(clientBus.toObserverable().subscribe(new Action1<Object>() {
        @Override
        public void call(Object event) {
            Log.e("New Event", "Event Received");
            if (event instanceof MyGcmListenerService.Message) {
                String msg = ((MyGcmListenerService.Message) event).getMessage();
                if (msg.equals("Update Available")) {
                    scheduleArrayList = getSchedules();
                    scheduleAdapter = new ScheduleAdapter(getApplicationContext(), scheduleArrayList, ScheduledUberActivity.this);
                    scheduledList.setAdapter(scheduleAdapter);
                    scheduleAdapter.notifyDataSetChanged();
                } else if (msg.equals("Refresh")) {
                    fetchTrips();
                }
            }
        }
    }));
}

在 MyGcmListenerService 类中，我在收到新通知时执行了此操作

 private void sendRefreshNotif() {
    if (clientBus.hasObservers()) {<--It enters the if cause the Log prints. But, the activity doesn't get the message
        Log.e("Obervers", "Observers aren't null");
        clientBus.send(new Message("Refresh"));
    }
}

我不明白的是为什么它在这里不起作用？我用它在 Activity 和 fragment 之间进行交互。我关闭了我的应用程序以检查是否收到通知，它将进入此 block if (clientBus.hasObservers()) { 但它没有并启动应用程序并测试 Observer ，它注意到有一个活跃的观察者。有什么帮助吗？谢谢。

Answer 1

您似乎在 CompositeSubscription 和 MyApplication 中使用了 ClientBus 类的不同实例。尝试从 ClientBus 类创建一个单例，它对我来说很好。

public class ClientBus {

    public ClientBus(SingletonAccessor accessor) {}

    private static ClientBus instance;
    private static class SingletonAccessor{}

    public static ClientBus getInstance() {
        if (instance == null) instance = new ClientBus(new SingletonAccessor());
        return instance;
    }

    private final Subject<Object, Object> mBus = new SerializedSubject<>(PublishSubject.create());

    public void send(Object o) {
        mBus.onNext(o);
    }

    public Observable<Object> toObserverable() {
        return mBus;
    }

    public boolean hasObservers() {
        return mBus.hasObservers();
    }
}