android - How to exit all the Async task on cancellation of activity? -

according post below: http://techtej.blogspot.com.es/2011/03/android-thread-constructspart-4.html. says that:

in such cases, application not shutdown, foreground tasks have been closed or changed, background tasks need know of , try exit gracefully

to achieve this, calling cancel function on asynctask instances. right way? in image lazy loading, don't keep track of asynctasks alive (and fetching images), how android os cancel them too?

you can cancel asynctask checking thread(asynctask) object's status.

private example ex = new example();  class example asynctask<object, void, void> {     @override     protected void doinbackground(object... params) {         string result = null;         if(!iscancelled())             result = gethttprestmanager().send();         if(!iscancelled())  {             // codes         }         ...         return null;     } }  public boolean cancel() {     switch(ex.getstatus())  {     case running:     case pending:         return ex.cancel(true);     case finished:         return false;     }     return false; } 

after cancel thread, it's status returns running or finished. if status not pending, cannot execute thread. have initialize new thread object ex = new example() before every .execute().