Question

我正在尝试设置一个警报管理器，使其每15分钟运行一次，检查是否有任何内容已添加到数据库中，然后显示通知。然而，虽然我只是测试这个，但我试图在60秒后显示通知。

以下代码在应用程序打开或最小化时完美运行，但在应用程序关闭时从不调用。

主要活动（onCreate（））

Intent alarm = new Intent(this.context, AlarmReceiver.class);
    boolean alarmRunning = (PendingIntent.getBroadcast(this.context, 0, alarm, PendingIntent.FLAG_NO_CREATE) != null);
    if (!alarmRunning) {
        PendingIntent pendingIntent = PendingIntent.getBroadcast(this.context, 0, alarm, 0);
        AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
        alarmManager.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime(), 60000, pendingIntent);
    }

警报接收器

public class AlarmReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
    Intent background = new Intent(context, BackgroundService.class);
    context.startService(background);
}

}

后台服务

public class BackgroundService extends Service {

private final String TAG = getClass().getName();

private Boolean isRunning;
private Context context;
private Thread backgroundThread;

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

@Override
public void onCreate() {
    this.context = this;
    this.isRunning = false;
    this.backgroundThread = new Thread(myTask);
}

private Runnable myTask = new Runnable() {
    @Override
    public void run() {
        Log.d(TAG, "THE BACKGROUND SERVICE IS RUNNING");
        //Run actions
        showNotification(context);
        //
        stopSelf();
    }
};

private void showNotification(Context context) {
    Uri soundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);

    NotificationCompat.Builder mBuilder =   new NotificationCompat.Builder(context)
            .setSmallIcon(R.drawable.icon)
            .setContentTitle("Notification!") // title for notification
            .setContentText("Alarm Received")
            .setSound(soundUri)// message for notification
            .setAutoCancel(true); // clear notification after click
    NotificationManager mNotificationManager =
            (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
    mNotificationManager.notify(0, mBuilder.build());
}

@Override
public void onDestroy() {
    this.isRunning = false;
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    if (!this.isRunning) {
        this.isRunning = true;
        this.backgroundThread.start();
    }
    return START_STICKY;
}

}

清单

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

    <service android:name=".notification.BackgroundService" />

    <receiver android:name=".notification.AlarmReceiver"
        android:process=":remote"
        android:enabled="true"
        android:exported="true">
        <intent-filter>
            <action android:name="android.intent.action.BOOT_COMPLETED" />
        </intent-filter>
    </receiver>

我已阅读了几篇帖子，但似乎找不到如何解决这个问题的答案，以便在关闭应用时仍然可以显示/检查通知，关闭我的意思是用户从运行中移除应用的位置应用列表。

Answer 1

尝试更改闹钟代码：

        final int ALARM_ID = 1234; // your alarm id
        startAlarm(600); // trigger after 10 minutes

        public void startAlarm(int seconds) { // set alarm in seconds
            Intent intent = new Intent(this, AlarmReceiver.class);
            AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
            PendingIntent pendingIntent = PendingIntent.getBroadcast(this, ALARM_ID, intent, PendingIntent.FLAG_CANCEL_CURRENT);

            alarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (seconds * 1000), pendingIntent);
        }

        public void cancelAlarm() { // to cancel alarm before trigger   
            Log.d("lucas", "cancelAlarm");
            Intent intent = new Intent(this, AlarmReceiver.class);
            AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
            PendingIntent pendingIntent = PendingIntent.getBroadcast(this, ALARM_ID, intent, PendingIntent.FLAG_CANCEL_CURRENT);

            alarmManager.cancel(pendingIntent);
            pendingIntent.cancel();
        } 

        public boolean hasAlarm() { // check alarm is running
            Intent intent = new Intent(this, AlarmReceiver.class);
            return (PendingIntent.getBroadcast(this, ALARM_ID, intent, PendingIntent.FLAG_NO_CREATE) != null);
        }

不调用 stopSelf()方法，他可能会杀死应用程序。后台运行的服务使应用程序进程保持活动状态。如果没有服务运行，系统可能会终止您的应用，删除通知并取消正在运行的警报。

提示：点击或取消通知时调用方法stopSelf()。

Answer 2

通过使用onTaskRemoved（）重新启动服务来管理解决此问题。

@Override
public void onTaskRemoved(Intent rootIntent) {
    Log.i(TAG, "onTaskRemoved()");

    Intent restartServiceIntent = new Intent(getApplicationContext(), this.getClass());
    restartServiceIntent.setPackage(getPackageName());

    PendingIntent restartServicePendingIntent = PendingIntent.getService(getApplicationContext(), 1, restartServiceIntent, PendingIntent.FLAG_ONE_SHOT);
    AlarmManager alarmService = (AlarmManager) getApplicationContext().getSystemService(Context.ALARM_SERVICE);
    alarmService.set(
            AlarmManager.ELAPSED_REALTIME,
            SystemClock.elapsedRealtime() + 1000,
            restartServicePendingIntent);

    super.onTaskRemoved(rootIntent);
}

应用关闭时不会触发通知

2 个答案: