Android Calling Asynctask Right After an Another Finished

Android calling AsyncTask right after an another finished

you can use getStatus() checks whether the the AsyncTask is pending, running, or finished.and when finsh start your new task.like:

if(authTask .getStatus() == AsyncTask.Status.PENDING){
    // My AsyncTask has not started yet
}

if(authTask .getStatus() == AsyncTask.Status.RUNNING){
    // My AsyncTask is currently doing work in doInBackground()
}

if(authTask .getStatus() == AsyncTask.Status.FINISHED){
    // START NEW TASK HERE
}

example for your app:

btn.setOnClickListener(new View.OnClickListener()
  {
    public void onClick(View v)
      {
        if (authTask != null && authTask.getStatus() == AsyncTask.Status.FINISHED) {
           //START YOUR NEW TASK HERE
        }
        else
        {
          //IGNORE BUTTON CLICK
        }
      }
   }); 

Start AsyncTask from another AsyncTask doInBackground()

According to the post below you can do Activity.runOnUiThread() to run a Runnable on the main-Thread (from another thread).

• Running code in main thread from another thread

So theoretically you could do this:

• Run the Async Task
• do Activity.runOnUiThread(Runnable) inside your AsyncTask and start a new AsyncTask from inside of this runnable

As the name says Activity.runOnUiThread() executes the runnable on the main-thread

But it's kind of hacky.

Code should look something like this: (didnt test)

// first task
    (new AsyncTask<String, String, String>() {

        @Override
        protected String doInBackground(String... params) {
            ParentActitity.this.runOnUiThread(new Runnable() {

                @Override
                public void run() {
                    //second async stared within a asynctask but on the main thread
                    (new AsyncTask<String, String, String>() {

                        @Override
                        protected String doInBackground(String... params) {
                            // TODO Auto-generated method stub
                            return null;
                        }

                    }).execute();

                }
            });
            return null;
        }

    }).execute();

This nested example is not a good style to use in production because (IMHO) its close to unreadable.

Additional Notes:

Activity.runOnUiThread(Runnable) is not static! Thats why my example uses ParentActivity(.this).runOnUiThread(Runnable).

Waiting till the async task finish its work

wait until this call is finish its executing

You will need to call AsyncTask.get() method for getting result back and make wait until doInBackground execution is not complete. but this will freeze Main UI thread if you not call get method inside a Thread.

To get result back in UI Thread start AsyncTask as :

String str_result= new RunInBackGround().execute().get();

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