Android AsyncTask - Order of execution

Question

I am facing an issue regarding the order of exection of AsyncTasks.

My question is :

Assuming I have 2 implementations of AsyncTask : MyAsyncTask1

Answer 1

In order to "chain" any number of AsyncTasks, what I do is have my AsyncTasks recieve a custom Callback as a parameter. You just have to define it like this:

public interface AsyncCallback(){
    public void onAsyncTaskFinished();
}

Your AsyncTask implementation constructor should have an AsyncCallback as a parameter, like this:

private AsyncCallback callback;

public AsyncTaskImplementation(AsyncCallback callback){
    //Do whatever you're doing here
    this.callback = callback;
}

Of course if they have more parameters, don't delete them.

Then, just before the end of onPostExecute, introduce this:

if (callback != null) callback.onAsyncTaskFinished();

So, if you pass a callback, the AsyncTask will execute your callback in the main thread. If you don't want to execute any callback, just pass null

So, to call your AsyncTask chain you just write this:

new AsyncTask1(new AsyncCallback(){

    public void onAsyncTaskFinished(){
         new AsyncTask2(null).execute();
    }

}).execute();

I hope this helps you ;-)