How to translate ImageView right and left in Activity class continuously

Question

I want to move ImageView (man.png) from right to left in Activity class(implements Runnable). I am using Man.setTranslationX(float x); to move... Here is my code Man is not moving by run() method ..

public class PlayScreen extends Activity implements Runnable{

float ManX=100;
Thread thread=new Thread(this);
//some code here(removed)

public void ManImageView() {


  Man = (ImageView)findViewById(R.id.stickman);                                        
  Man.setVisibility(ImageView.VISIBLE);
  thread.start();  
}

@Override
public void run(){
    Man.setTranslationX(ManX);
    ManX++;
try{
thread.sleep(500);}
catch{
   }

}

is there any way to update ur screen continuously like invalidate(); method in View class.. or there is some problem with Thread running??? Here is .xml of ImageView

<ImageView
  android:id="@+id/stickman"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignParentBottom="true"
  android:layout_alignParentLeft="true"
  android:layout_marginLeft="50sp"
  android:layout_marginBottom="15sp"
  android:src="@drawable/image1"/>

Please Help