多个告警调用同一服务

Question

我有多个报警调用广播意图，而广播意图又调用位置服务。这个想法是在不同的时间获得位置。位置服务需要一段时间才能返回位置，之后它会关闭。我想知道当两个警报同时调用这个公共位置服务时会发生什么，或者说警报1已经调用了位置服务，而第二个警报2也称为位置服务，因为我已经读取了服务只有一个实例。

还有，处理我上面提到的这种情况的最好方法是什么？

Intent intent = new Intent(context, NotificationView.class);
 PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);

    alarmManager.set(AlarmManager.RTC_WAKEUP, dateTime.getTimeInMillis(), pendingIntent);

在我的NotificationView.class中，我调用服务

Intent serviceIntent = new Intent(context,MyLocationService.class);
    context.startService(serviceIntent); //start service for get location

可以在通过该待定意图调用该相同服务的某些secods的差异内调度多个警报。

Answer 1

是的，你说得对。我展示了我的代码，其中我的请求代码是i变量。您可以为您更改它

public static void setAlarmReceiver(Context context, ArrayList<CheckPoint> checkPoints) {

        clearAlarmReceiver(context);

        if (checkPoints.size() == 0)
            return;

        int i = 0;
        for (CheckPoint checkPoint : checkPoints) {
            Intent intent = new Intent(context, CheckAlarmReceiver.class);
            intent.putExtra("checkPoint", checkPoint);
            PendingIntent pendingIntent = PendingIntent.getBroadcast(context, i, intent, PendingIntent.FLAG_CANCEL_CURRENT);
            Calendar calendar = Calendar.getInstance();
            calendar.set(Calendar.DAY_OF_MONTH, Integer.valueOf(getDay(checkPoint.getDate())));
            calendar.set(Calendar.MONTH, Integer.valueOf(getMonth(checkPoint.getDate())) - 1);
            calendar.set(Calendar.YEAR, Integer.valueOf(getYear(checkPoint.getDate())));
            calendar.set(Calendar.HOUR_OF_DAY, Integer.valueOf(getHour(checkPoint.getCheckInTime())));
            calendar.set(Calendar.MINUTE, Integer.valueOf(getMinute(checkPoint.getCheckInTime())));
            calendar.set(Calendar.SECOND, 0);
            AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
            if (android.os.Build.VERSION.SDK_INT >= 19) {
                alarmManager.setExact(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
            } else {
                alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
            }

            i++;
        }
    }

Answer 2

在我看来，最好解决方案是创建辅助类，它将是缓存位置，并防止例如对服务的额外调用。

public class LocationHelper {
  public static AbstractMap.SimpleEntry<Long, Location> cache = null; //location stored here
  public static int expiryTime = 5000; // 5 seconds for example

  private static boolean requested = false;

  private static List<LocationListener> callbacks = new ArrayList<>();// request heap

  public static void getLocation(LocationManager lm, LocationListener ll){
    Long currentTimeStamp = getTimeStamp();
    final LocationListener mLocationListener = new LocationListener() {
       @Override
       public void onLocationChanged(final Location location) {
         cache = new AbstractMap.SimpleEntry<>(getTimeStamp(), location);

         synchronized(LocationHelper.class){
           for(LocationListener loclist : callbacks){
             loclist.onLocationChanged(location); // call each listener
           }
           callbacks.clear(); 
           requested = false;
         }
       }
    };
    if (cache != null && currentTimeStamp - cache.getKey() < expiryTime){
      ll.onLocationChanged(cache.getValue());
    } else {
       if(!requested){
         synchronized(LocationHelper.class){ // synchronize class to prevent thread collision and additional request
           if(!requested){
             lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, LOCATION_REFRESH_TIME, LOCATION_REFRESH_DISTANCE, mLocationListener);
             requested = true;
           }
         }
       } else {
         synchronized(LocationHelper.class){
           callbacks.add(ll);
         }
       }
    }
  }

  public static Long getTimeStamp(){/*some code here*/}
}

这个解决方案有点复杂，但它应该是可行的