Question

I’m learning android, and I got into a little problem.
I’ve got a button I want to move to the right side of the screen, after i click on it.
I added a timer that starts after the button gets clicked, but when I click on the button the program/activity crashes.

here is the code:

import android.app.Activity;
import android.graphics.Point;
import android.os.Bundle;
import android.view.Display;
import android.view.View;
import android.widget.Button;

public class Testing extends Activity{

Timer timer = new Timer();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.testing_layout);

    final Button bt = (Button)findViewById(R.id.testButton);

    bt.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            timer.scheduleAtFixedRate(new TimerTask(){
                @Override
                public void run() {
                    float btLoc = bt.getX();
                    bt.setX(btLoc+= 50);
                }
            }, 2000, 2000);


        }
    });
}

this same piece of code that moves the button worked before without the timer. I have no idea why the program crashes when the onClick(View v) executes.

(sorry for my english)

Answer 1

Use runOnUiThread for Updating UI from non UI Thread :

@Override
public void onClick(View v) {
  timer.scheduleAtFixedRate(new TimerTask(){
    @Override
      public void run() {

       Testing.this.runOnUiThread(new Runnable() {
           public void run() {
             //update ui here
              float btLoc = bt.getX();
              bt.setX(btLoc+= 50);
        }
      });
        }
     }, 2000, 2000);

  }
});