在日期和时间更改时重置/取消警报时发生AlarmManager错误

Question

I want to send data to server at some regular interval. So, I am using AlarmManager for the same. It works fine but the problem is that when I cancel the Alarm on Date/Time change. At that time Alarm fires again before getting cancelled, so that makes my application worse as an extra data is sent to server with irregular interval.

Here is my BroadCastReceiver class with AlarmManager .

 public class MyReceiver extends BroadcastReceiver{

    AlarmManager mgr;
    PendingIntent pi;
    Intent intent;
    public static boolean flag = false;

    @Override
    public void onReceive(final Context arg0, Intent arg1) {

        if(arg1.getAction().equals("android.intent.action.TIME_SET")){
            Log.d("MyReceiver", "Time set");

            mgr = (AlarmManager) arg0.getSystemService(Context.ALARM_SERVICE);
            intent = new Intent(arg0, TestService.class);
            intent.putExtra("test", "testvalue");
            pi = PendingIntent.getService(arg0, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);

            if(!flag){
                mgr.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + 10000, 5000, pi);
                flag = true;
            }
            else{
                mgr.cancel(pi);
                pi.cancel();
                flag = false;
            }
        }
    }
}

Below is the Screen Shot with Logcat output that explains that after cancelling the Alarm it fires once more time just after cancelling.

As you can see in the Logcat output black arrow shows where I changed that time to cancel the Alarm and red arrow shows that after cancelling the Alarm once again it fired just before cancelling which should not happen. So, can anyone give my idea why that is happening and what should I do to restrict Alarm getting fired again before cancelling.

NOTE:- This only happens when I tried to increase date/time say from 10:00 to 11:00, works perfect when I decrease time say 10:00 to 9:00.

Answer 1

Not able to see the LogCat at my end, but looking at the code, I am not sure, how is the Service which gets invoked (TestService) gets killed / stopped ? I think you would need to stop it somehow. Also, its not recommended to do long running tasks within the broadcast receiver. Have you verified that you service stop event is occuring after the mgr.cancel(pi) is fired?

Answer 2

Just try with some unique code with pending intent within activity and then cancel that intent using the same code.

setting pending intent in activity

PendingIntent.getBroadcast(this, code , intent, PendingIntent.FLAG_UPDATE_CURRENT);

for stopping that broadcast receiver

PendingIntent pendingIntent = PendingIntent.getBroadcast(getBaseContext(), code , intent, 0); AlarmManager alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE); alarmManager.cancel(pendingIntent);

Answer 3

why that is happening

First Thing is that you are using Intent Action android.intent.action.TIME_SET so It does mean that Everytime any how if the System date/time gets Changed your BroadcastReceiver will ne called Automatically.

Second you have used one static boolean flag in your Receiver class. Now what is happening is Whenever you change your System timings the flag toggles it's state from false to true and from true to false .

That is what exactly happening in your code and logcat also shows the same that everything is working as per the code written.

So according to me there is nothing Wrong happening in the code and it's output.

what should I do to restrict Alarm getting fired again before cancelling

First thing as I think, you should not use Action TIME_SET like that to toggle flag on/off as users and developers might not remember for what they are changing time either to turn FLAG On or Off,

Better way is that, you should handle the Service yourself by an Activity and show one ToggleButton there to manage the State of the FLAG and set and cancel the PendingIntent.

OR And If you want to do the task of your service automatically then you just simply use the AlarmManager and set your Alarm Triggering time and Interval there only once say time is currenttime and Interval is 50000 miliseconds..

so it will obviously call the service from now onwards after every 5mins, then in your App you will only require one ToggelButton to indciate the Sync to ther server is On or Off , if user Toggle it on or off then write your AlarmManager code there in your Activity only in the toggleButtontb.setOnCheckedChangeListener(listener) , I suppose this is the better way then what you are actually implementing.

Answer 4

I don't understand what need to set the receiver for date change if your goal is only to send the data on server in some regular interval .

change date and time of device does not mean that your alarm wont work at that time which you already have set before those changes . Alarmmanager work on that given duration of time which is excluding from local current date and time of device .