How to run the same asynctask more than once?

Question

I have my asyncTask run when the activity first starts, then if network connectivity is not available then i have a refresh button that tries to run the asyncTask to try aga

Answer 1

You cannot run same instance of an AsyncTask more than once. Let's assume you have an AsyncTask named MyAsyncTaks and you intend to do something like this,

    MyAsyncTask myAsyncTask = new MyAsyncTaks();
    myAsyncTask.execute(); // Works as expected
    .
    .
    .
    .
    myAsyncTask.execute(); // This will throw you exception

The reason for this is, a thread once finishes its 'run' method, cannot be assigned another task. Here, on the first invocation of execute(), your AsyncTask started running and after doing its job, the thread comes out of run. Naturally, next invocation of execute() will throw you exception.

The simplest way to run this more than once is to create a new instance of MyAsyncTaks and call execute on that.

    MyAsyncTask myAsyncTask = new MyAsyncTaks();
    myAsyncTask.execute(); // Works as expected
    .
    .
    .
    MyAsyncTask myAsyncTask2 = new MyAsyncTaks();
    myAsyncTask2.execute(); // Works as expected

Though its not needed to be mentioned here, one must be aware that post Android SDK version Honeycomb, if your run more than one AsyncTask at once, they actually run sequentially. If you want to run them parallally, use executeOnExecutor instead.