AlarmManager and BroadcastReceiver instead of Serv

Question

BACKGROUND INFO:

I need to update some data from the web, about every hour or so, even when my app is closed. The update of the data itself takes about 40 seconds to 1 minute. It is then saved as a Serializable to a file. This file is read when my app starts.

THIS IS THE APPROACH I TOOK FOR THE MOMENT (not using a Service)

use the AlarmManager and BroadcastReceiver like this :

private void set_REFRESH_DATA_Alarm(){
    mContext = Main.this;
    alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
    broadcast_intent = new Intent(mContext, 
            RepeatingAlarmReceiver_REFRESH_DATA.class);
    pendingIntent = PendingIntent.getBroadcast(mContext, 0,  broadcast_intent, 0);
    // do a REFRESH every hour, starting for the first time in 30 minutes from now ...
    Calendar now = Calendar.getInstance();
    long triggerAtTime = now.getTimeInMillis()+ (1 * 30 * 60 * 1000); // starts in 30 minutes
    long repeat_alarm_every = (1 * 60 * 60 * 1000); // repeat every 60 minutes
    alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, triggerAtTime, 
            repeat_alarm_every, pendingIntent);
}

My RepeatingAlarmReceiver_REFRESH_DATA.class takes care of updating the Data from the Web:

public class RepeatingAlarmReceiver_REFRESH_DATA extends BroadcastReceiver {

    public static Context mContext;
    ConnectivityManager mConnectivity;

    @Override
    public void onReceive(Context context, Intent intent) {
        mContext = context;
        // if Network connection is OK (Wifi or Mobile) then Load data ...
        mConnectivity = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        Log.i("Hub",
                "mConnectivity.getNetworkInfo(0)="
                        + mConnectivity.getNetworkInfo(0));
        Log.i("Hub",
                "mConnectivity.getNetworkInfo(1)="
                        + mConnectivity.getNetworkInfo(1));
        if ((mConnectivity.getNetworkInfo(0).getState() == NetworkInfo.State.CONNECTED)
                || (mConnectivity.getNetworkInfo(1).getState() == NetworkInfo.State.CONNECTED)) {
            Log.i("Hub", "Connectivity OK ...");
            Refresh_HIST_DATA();
        } else {
            // else Show Dialog "No network connection" ...
            Log.i("Hub",
                    "No network connection for the moment... will try again later!");
        }
    }

    // =========================================================================
    private void Refresh_HIST_DATA() {
        Log.i("Hub", "Refresh_HIST_DATA()... Starting ...");
        // etc...
    }
}

In the Manifest I have :

<receiver android:name="com.cousinHub.myapp.RepeatingAlarmReceiver_REFRESH_DATA" android:process=":remote" />

PROBLEM :

The alarm gets fired on time and the update starts but then after about 10 seconds it stops (Timeout):

06-25 11:55:05.278: WARN/ActivityManager(76): Timeout of broadcast BroadcastRecord{44bb4348 null} - receiver=android.os.BinderProxy@44bcc670

06-25 11:55:05.278: WARN/ActivityManager(76): Receiver during timeout: ResolveInfo{44bb42c0 com.cousinHub.myapp.RepeatingAlarmReceiver_REFRESH_DATA p=0 o=0 m=0x0}

06-25 11:55:05.278: INFO/Process(76): Sending signal. PID: 819 SIG: 9

06-25 11:55:05.298: INFO/ActivityManager(76): Process com.cousinHub.myapp:remote (pid 819) has died.

ps: strangely enough, this "Timeout" does not happen after about 10 seconds on my HTC Hero (still on Android 1.5 - API Level 4) but well on my Nexus One (2.1-update1)

Questions :

1. Why this timeout ? Any easy way to avoid this ?
2. Did I set up my BroadcastReceiver correctly in the manifest ? Do I need to add something (to avoid this timeout) ?
3. Should I absolutely go for a Service for this kind of "Refresh from Web" functionality ? (considering this article : http://www.androidguys.com/2009/09/09/diamonds-are-forever-services-are-not/) If YES (I should switch to a service): Any good snippets of code/tutorial for this ...

As allways, thanks for your help.

H.

Answer 1

Why this timeout ?

You are running on the main application thread. You cannot run on the main application thread for more than a few seconds. Also, while doing this, you are harming the performance of the device (because you are running with foreground priority), such as causing frame-rate loss in games or videos.

Any easy way to avoid this ?

Don't do significant work (>100ms) on the main application thread. Have your BroadcastReceiver delegate to an IntentService, perhaps a WakefulIntentService.

Did I set up my BroadcastReceiver correctly in the manifest ?

Please please please please please get rid of the android:process=:remote. You do not need it, it is not helping you, and it is degrading performance of the device even further.

Should I absolutely go for a Service for this kind of "Refresh from Web" functionality ? (considering this article : http://www.androidguys.com/2009/09/09/diamonds-are-forever-services-are-not/) If YES (I should switch to a service): Any good snippets of code/tutorial for this ...

IMHO, yes. Then again, I wrote that blog post. For an example, see the WakefulIntentService project.

Answer 2

For information, I've tried with a new thread and it works when on Wifi (takes about 1'30" to update the data when phone is asleep, it doesn't get 'killed' !

//let's try with a new separate thread ?
        new Thread(new Runnable() {
            public void run() {
                Refresh_HIST_DATA();
            }
          }).start();

but NOT when on Mobile (GPRS), as it gets killed after about 10 secs!

It's half-a-solution for the moment and I will try CommonsWare's solution for a cleaner/more sustainable approach...

Let's see if the new thread solution works allways fine or was just luck (I've tested only during a couple hours) ...

If anyone else has another suggestion, please do post it.

Answer 3

Instead of thread. You can start a AsyncTask from your broadcast receiver onRecive() method. This will not block the UI thread. I myself have done same in my projects which is of same nature i.e. It has to post data every 1 hour.

public void onReceive(Context context, Intent intent) {
        // start your Asynctask from here. which will post data in doInBackground() method
}