How to update UI on external asynctask on android

Issue

MainActivity execute external asynctask class

Here my code

public class MainActivity extends AppCompatActivity implements View.OnClickListener
...
public void onFirstBtnClick()
{
    AysncClass ac = new AyncClass();
    ac.execute();
}

and external asynctask

public class AysncClass extends AsyncTask<String, String, Integer>

    @Override
    protected Integer doInBackground(String... strings) {
        Method1(strings[0], Integer.parseInt(strings[1]));
        return null;
    }

    public Method1(Strins s, int i)
    {
        onProgressUpdate("first start");
        publishProgress();
        // do more work
        onProgressUpdate("second start");
        publishProgress();
    }

    public void Method2()
    {
        onProgressUpdate("Method2 here");
        publishProgress();
    }
    ...
     @Override
    protected void onProgressUpdate(final String... values) {
    super.onProgressUpdate(values);
    // what can i do here?
    }
}

I use runOnUiThread like this in onProgressUpdate

    ((MainActivity)context).runOnUiThread(new Runnable()
    {
        @Override
        public void run()
        {
            ((MainActivity)context).tvRead.append(values[0]);
        }
    });*

but It occur 'java.lang.ArrayIndexOutOfBoundsException: length=0; index=0' even though values[0] is not null.

Also I use interface

this.context.WriteText(values[0]);

It occur same error

And I do this...

((MainActivity)context).tvRead.append(values[0]);

It occur 'java.lang.RuntimeException: An error occured while executing doInBackground()' and 'CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.'

...How can I resolve?

Solution

Do not call onProgressUpdate(). Instead just call publishProgress("The String").

By calling publishProgress without a parameter you will have no values in onProgressUpdate. That's why you get an IndexOutOfBondException.

Answered By - Murat Karagöz