Question

我创建了一个警报管理器，每隔5秒启动一次服务，应用程序运行良好但几小时后警报管理器停止运行。请注意，用户不使用该应用程序，这意味着它在没有用户交互的情况下在后台运行。有没有人知道如何在不停止的情况下每隔一秒启动一次服务？

AlarmManager am = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(context, AlarmManagerBroadcastReceiver.class);
intent.putExtra(ONE_TIME, Boolean.TRUE); 
PendingIntent pi = PendingIntent.getBroadcast(context, 0, intent, 0);
am.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (1000 * 60 * 5), pi);

Answer 1

请勿使用警报管理器执行此类操作。报警管理器更多应该在几个小时内完成任务的概念（在最好的情况下）。

如果您需要精确处理任务，请在里面使用处理程序一个服务，该帖子执行你的runnable。在runnable中，调用方法再次执行runnable。

将runnable和handler保存为服务的成员变量并make 这个过程很粘。如果要停止服务和处理程序（处理程序不会如果您只是调用stopService（Context）或Service.stopSelf（），则需要停止使用处理程序上的runnable调用removeCallbacks（runnable）。

干杯。

Btw ：想想你是否真的想要每5秒启动一次服务。也许只是在服务的可运行内部进行服务工作我刚刚描述过。

Edit2 ：如果您需要服务可靠，请添加一个BroadcastReceiver for Boot Actions，它将在启动时接收广播并重新启动您的服务。

Edit3 ：代码检查您的服务是否正在运行，而不启动它：

    public static boolean isRunning(Context context) {
    ActivityManager manager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    for (ActivityManager.RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
        if (YourService.class.getName().equals(service.service.getClassName())){
            return true;
        }
    }
    return false;
}

但是，请检查onStartCommand，您的成员'handler'不为null 如果是，则忽略一个启动请求，因为这可能会导致您遇到多个可运行处理的情况。

<强> Edit4：

服务代码段：

public class LoopingServiceSnipped extends Service{

public static final long STANDARD_FREQUENCY = 1000;
private static       long         loopingFrequency         = STANDARD_FREQUENCY;
private Handler  serviceHandler; 
private Runnable loop; 

//EXTRAS

private static final String       INTENT_EXTRA_STOP_SERVICE  = LoopingServiceSnipped.class.getSimpleName() + "_INTENT_EXTRA_STOP_SERVICE";
private static final String       INTENT_EXTRA_FREQUENCY     = LoopingServiceSnipped.class.getSimpleName() + "_INTENT_EXTRA_FREQUENCY";

/**
 * Determines if the service is running (reliably) without starting it.
 *
 * @param context
 *         needed for SystemServices
 *
 * @return true if the service is running
 */
public static boolean isRunning(Context context) {
    ActivityManager manager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    for (ActivityManager.RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
        if (LoadingScreenAppDetectionService.class.getName().equals(service.service.getClassName())){
            return true;
        }
    }
    return false;
}

public static void stopService(Context c) {
    Intent i = new Intent(c, LoopingServiceSnipped 
    i.putExtra(INTENT_EXTRA_STOP_SERVICE, true);
    c.startService(i);
 }

public static synchronized void setFrequency(Context c, long frequency) {
    Intent i = new Intent(c, LoadingScreenAppDetectionService.class);
    i.putExtra(INTENT_EXTRA_FREQUENCY, frequency);
    c.startService(i);
}

@Override
public void onCreate() {
    super.onCreate();
    init();
}

private void init() {
    //do your initialization here
}

@Nullable
@Override
public IBinder onBind(Intent intent) {
    return null;
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    if (shouldStopService(intent)){
        LOG.d("Going to stop service!");
        tryStopService();
        return Service.START_NOT_STICKY;
    } else {
        return startOrContinueService(intent);
    }
}

private void tryStopService() {
    stopLooping();
    stopSelf();
}

private void stopLooping() {
    if (serviceHandler != null){
        serviceHandler.removeCallbacks(getLoop());
        serviceHandler = null;
    }
}

private int startOrContinueService(Intent intent) {
    if (hasNewFrequency(intent)){
        setFrequency(intent);
        stopLooping();
    }
    if (!isServiceRunning()){
     startLooping();
        }
    } else {
        LOG.d("Going to continue with service!");
    }
    return Service.START_STICKY;
}


private boolean hasNewFrequency(Intent intent) {
    return intent.hasExtra(INTENT_EXTRA_FREQUENCY);
}

private void setFrequency(Intent intent) {
    if (intent.hasExtra(INTENT_EXTRA_FREQUENCY)){
        loopingFrequency = intent.getLongExtra(INTENT_EXTRA_FREQUENCY, STANDARD_FREQUENCY);
    }
}

private boolean isServiceRunning() {
    return serviceHandler != null;
}

private boolean shouldStopService(Intent i) {
    if (i.hasExtra(INTENT_EXTRA_STOP_SERVICE)){
        return i.getBooleanExtra(INTENT_EXTRA_STOP_SERVICE, false);
    } else {
        return false;
    }
}

private void startLooping() {
    if (serviceHandler == null){
        serviceHandler = new Handler();
    }
    serviceHandler.postDelayed(getAppDetectionLoop(), getFrequency());
}

private Runnable getLoop() {
    if (loop == null){
        loop = new Runnable() {
            @Override
            public void run() {
                //do your looping work here
                startLooping();
            }
        };
    }
    return loop;
}

另外添加Boot Receiver和Screen TurnOn Receiver。

android警报管理器在几个小时后停止

1 个答案: