Running task periodicaly(once a day/once a week)

问题:

I want to run some task (i.e. get my web site news page) periodically (once a week/ a day), even if my application is closed. Is it possible?

回答1:

Yes it is, you need to look at the AlarmManager to setup a reoccurring "Alarm". This is better for battery life on the device, as unlike a service it does not run constantly in the background. The Alarm triggers a broadcast receiver which will execute your custom code.

As a final note - there are enum values for the timing of the Alarm including daily, half daily and many more although you can just set an actual value.

A good example can be found in the follow SO post:

Alarm Manager Example

Update

Newer features have been added to Android. If you are reading this then I would advise you now look into GcmNetworkManager. This optimises battery life and works pre-lollipop. For Lollipop onwards you can use JobScheduler. I would advise using these classes over the AlarmManager.

回答2:

I think the best fit is GcmNetworkManager. Basically it has everything you need from AlarmManager plus persistence, so job can proceed executing after reboot.

Example:

PeriodicTask task = new PeriodicTask.Builder()
        .setService(MyTaskService.class)
        .setTag(TASK_TAG_PERIODIC)
        .setPeriod(5L)
        .build();

mGcmNetworkManager.schedule(task);

回答3:

As an alternative I'm comparing the current week:

Calendar cal = Calendar.getInstance();
int currentWeekOfYear = cal.get(Calendar.WEEK_OF_YEAR);

SharedPreferences sharedPreferences= this.getSharedPreferences("appInfo", 0);
int weekOfYear = sharedPreferences.getInt("weekOfYear", 0);

if(weekOfYear != currentWeekOfYear){
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putInt("weekOfYear", currentWeekOfYear);
    editor.commit();
    // Your once a week code here
}

I'm not advocating this is better than the Alarm solution. I'm just showing a different approach.