AsyncTask: how to communicate with another class with onProgressUpdate

Question

I have set up an AsyncTask .

In doInBackground() , the only job is to call a method from another class. That method was copied from an old Java Applet, so while executing, it would print out progress every 10% onto the screen directly until finish. As this is not advisable in Android, I use AsyncTask to run it.

My question is, how to capture the Integer progressPercent spit out from that method in doInBackground() , and pass onto onProgressUpdate() to update the UI? How should I modify the original method to cope with the AsyncTask structure?

Answer 1

I think you need a Handler for that, because doInBackground() will be called only once, so you cannot display the progress with that. You can update a progress bar for example with the handler in every 10% or even more often.

Answer 2

First the AsyncTask class should be on the form

class Task extends AsyncTask<Object, Long, Object> 
// or 
class Task extends AsyncTask<Object, Integer, Object> 

then edit the part that prints out progress every 10% inside the Task to

publishProgress(/*your progress here*/);

and finally your onProgressUpdate and its parameter depends on the object that you choose in the class definition

@Override
protected void onProgressUpdate(Long... values) {
    long progress = values[0];
    // update UI here
}
// if you choose object Integer
@Override
protected void onProgressUpdate(Integer... values) {
    int progress = values[0];
    // update UI here
}

BTW: You can use a loop to show the progress many times instead of just once.