带有 IntentService 的 Android RxJava 间隔

Question

我对 rxjava 很陌生，所以我想将它与 android IntentService 一起使用，并且我需要在特定时间段内每秒收到一次通知(类似于 Android CountDownTimer。我决定尝试与 rxjava 一起使用，并且我有这个类:

public class WorkoutService extends IntentService {
public static final String BUNDLE_EXTRA_MESSENGER = "messenger";
public static final String BUNDLE_EXTRA_NUMBER_ROUNDS = "nr_rounds";
public static final String BUNDLE_EXTRA_WORKOUT_DURATION = "workout_duration";
public static final String BUNDLE_EXTRA_PAUSE_DURATION = "pause_duration";
private static final int NOTIFICATION_ID = 1;
public static final int UPDATE_PROGRESS = 2;

/**
 * Target we publish for clients to send messages to IncomingHandler.
 * This is the messenger from the activity
 */
Messenger messenger;

private NotificationManager notifyManager;
private NotificationCompat.Builder builder;
private volatile int maxProgress;
private int numberOfRounds = 4;
private int workoutDuration = 7 * 60; //7 minutes
private int pauseDuration = 90; //1.5 minutes
private int currentProgress;

public WorkoutService() {
    super("WorkoutService");
}

@Override
protected void onHandleIntent(Intent intent) {
    Bundle extras = intent.getExtras();
    if (extras != null) {
        messenger = (Messenger) extras.get(BUNDLE_EXTRA_MESSENGER);
        numberOfRounds = extras.getInt(BUNDLE_EXTRA_NUMBER_ROUNDS, numberOfRounds);
        workoutDuration = extras.getInt(BUNDLE_EXTRA_WORKOUT_DURATION, workoutDuration);
        pauseDuration = extras.getInt(BUNDLE_EXTRA_PAUSE_DURATION, pauseDuration);
    }
    maxProgress = numberOfRounds * workoutDuration + ((numberOfRounds - 1) * pauseDuration);
    maxProgress = 10; //TODO: for testing
    showNotification(maxProgress);
    Timber.d("maxProgress %d", maxProgress);
    startWorkout();

}

private void startWorkout() {
    final Observable<Long> observable = Observable
            .interval(1, TimeUnit.SECONDS);
    observable
            .subscribeOn(Schedulers.io())
            .subscribe(new Subscriber<Long>() {
                @Override
                public void onCompleted() {
                    Timber.d("onCompleted");
                    unsubscribe();
                    stopForeground(true);
                    stopSelf();

                }

                @Override
                public void onError(Throwable e) {
                    Timber.e("onError");
                }

                @Override
                public void onNext(Long aLong) {
                    Timber.d("onNext : " + aLong + "S");
                    updateProgress();
                    if (aLong == maxProgress) {
                        onCompleted();
                    }
                }
            });
}

private void showNotification(int maxProgress) {
    Intent notificationIntent = new Intent(this, WorkoutService.class);
    PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);
    notifyManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    builder = new NotificationCompat.Builder(this);
    builder.setContentTitle(getString(R
            .string.notification_title))
            .setContentIntent(pendingIntent)
            .setSmallIcon(R.mipmap.ic_launcher);
    startForeground(NOTIFICATION_ID, builder.build());
    currentProgress = 0;
    builder.setProgress(maxProgress, currentProgress, false);
    notifyManager.notify(NOTIFICATION_ID, builder.build());
}

private void sendMessageToActivity(Message message) {
    try {
        if (messenger != null) {
            messenger.send(message);
        }
    } catch (RemoteException e) {
        Timber.e(e, "Error sending message to activity");
    }
}

private void updateProgress() {
    currentProgress++;
    builder.setProgress(maxProgress, currentProgress, false);
    notifyManager.notify(NOTIFICATION_ID, builder.build());
    Message message = Message.obtain(null, UPDATE_PROGRESS, currentProgress, 0);
    sendMessageToActivity(message);
}

}

问题是通知没有被取消，而它应该被取消，而且即使我明确调用 stopSelf()，服务似乎也没有停止。在android文档中它说当不再有工作要做时这个服务会自己停止但是因为我正在调用onCompleted并取消订阅应该不是这样吗？我怎样才能确保可观察对象停止发射并且流程终止？非常感谢

Answer 1

问题是，当 onHandleIntent 返回时，您的 Intent 服务已经终止。IntentServices 是一种非常特殊的服务，它在后台线程中执行 onHandleIntent 并被关闭。

通过这样做，您将泄漏该 intentservice 类，因为订阅者持有对它的引用。订阅完成后，您将在死(泄漏)服务上调用 stopSelf。

此外，在不同的线程中订阅是没有意义的，因为 onHandleIntent 本身是在不同的线程中运行的。

我认为您应该使用服务(而不是 Intent 服务)来实现您想要做的事情。