Firstly, you are making a UI thread sleep that's why your UI is getting freeze.Here, i have created a async task where i am sleeping background thread and running a UI update on main thread as you can see below in doInBackground method.Here is your solution -:
public class MainActivity extends Activity {
private ImageView leftImageButton;
private boolean leftButtonDown = false;
private ImageView knight;
private AsyncTask asyncTask = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
leftImageButton = (ImageView) findViewById(R.id.imageView2);
knight = (ImageView) findViewById(R.id.imageView1);
leftImageButton.setOnTouchListener(new LeftImageListener());
}
public void startTask() {
asyncTask = new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
if (leftButtonDown) {
while (leftButtonDown) {
try {
Thread.sleep(10);
runOnUiThread(new Runnable() {
@Override
public void run() {
try {
moveLeft(5);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
return null;
}
}.execute();
}
public void moveLeft(int speed) throws InterruptedException {
knight.setLeft(knight.getLeft() - speed);
}
public class LeftImageListener implements OnTouchListener {
public LeftImageListener() {
// TODO Auto-generated constructor stub
}
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
leftButtonDown = true;
startTask();
break;
case MotionEvent.ACTION_UP:
leftButtonDown = false;
break;
default:
break;
}
return true;
}
}
}