Android - Elaborar una aplicación para celulares táctiles, donde un objeto se mueva en la dirección

import android.app.Activity;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Paint;

import android.os.Bundle;

import android.view.Menu;

import android.view.MotionEvent;

import android.view.View;

import android.view.View.OnTouchListener;

import android.widget.RelativeLayout;

public class MainActivity extends Activity implements OnTouchListener {

    private int corx, cory;

    private Lienzo fondo;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        corx = 100;

        cory = 100;

        RelativeLayout layout1 = (RelativeLayout) findViewById(R.id.layout1);

        fondo = new Lienzo(this);

        fondo.setOnTouchListener(this);

        layout1.addView(fondo);

    }

    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.

        getMenuInflater().inflate(R.menu.menu_main, menu);

        return true;

    }

    public boolean onTouch(View v, MotionEvent event) {

        corx = (int) event.getX();

        cory = (int) event.getY();

        fondo.invalidate();

        return true;

    }

    class Lienzo extends View {

        public Lienzo(Context context) {

            super(context);

        }

        protected void onDraw(Canvas canvas) {

            canvas.drawRGB(255, 255, 0);

            Paint pincel1 = new Paint();

            pincel1.setARGB(255, 255, 0, 0);

            pincel1.setStrokeWidth(4);

            pincel1.setStyle(Paint.Style.STROKE);

            canvas.drawCircle(corx, cory, 20, pincel1);

        }

    }

}