Question

Just to be clear, this question is not about how to update a TextView from a Thread, that’s working fine. The problem is that even if I make multiple calls to update the TextView throughout the Thread, the updates only appear after the Thread is done it’s work. Here’s an example:

public class NDThread extends Thread {

    protected LogActionListener log_listener;
    private Handler handler = new Handler();


    public void run() {
        logAction("starting");
        // Do many things..
        logAction("halfway");
        // Many more things..
        logAction("done");
    }

    public interface LogActionListener {
        public void onLogAction(String paramString);
    }

    public void logAction(final String str) {
        if(log_listener != null) handler.post(new Runnable() {
            @Override
            public void run() {
                log_listener.onLogAction(str);          
            }       
        });
    }
}

And in my main Activity, I implement LogActionListener to recieve the Strings and update the TextView:

NDThread thread = new NDThread();
thread.setOnLogActionListener(this);
thread.run();

// Elsewhere..
@Override
public void onLogAction(final String msg) {
        handler.post(new Runnable() {

            @Override
            public void run() {
                textView.append(msg);
            }

        });
}

As you can see, I’ve used Handlers in both the Thread and the Activity because I wasn’t really sure which was correct to use. However, the result is always a blank TextView for the entirety of the Thread, then at the end it will print the 3 lines. What am I doing wrong?

Answer 1

Avoid Thread and Go For AsyncTask

What you are looking for is onProgressUpdate(Progress…) , publishProgress(Progress…) of AsyncTask

Google for their code samples.