/**  * ...  *  * @author vlinux  *  */ public class MultiTouchTestActivity extends Activity {  /** Called when the activity is first created. */  @Override  public void onCreate(Bundle savedInstanceState) {   super.onCreate(savedInstanceState);   // setContentView(R.layout.main);   View view = new MultiTouchView(this);   setContentView(view);  }  class MultiTouchView extends View {   private float x1;   private float y1;   private float x2;   private float y2;   public MultiTouchView(Context context) {    super(context);    // TODO Auto-generated constructor stub   }   @Override   public boolean onTouchEvent(MotionEvent event) {    // TODO Auto-generated method stub    float size = event.getSize();    int szi = (int) size;    int dxi = szi >> 12;    int dyit = ((1 << 12) - 1);    int dyi = szi & dyit;    DisplayMetrics metrics = getResources().getDisplayMetrics();    float dx = metrics.widthPixels * dxi / (float) dyit;    float dy = metrics.heightPixels * dyi / (float) dyit;    x1 = event.getX();    y1 = event.getY();    x2 = x1 + dx;    y2 = y1 + dy;    invalidate();    return true;   }   @Override   protected void onDraw(Canvas canvas) {    // TODO Auto-generated method stub    super.onDraw(canvas);    float r = (float) Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2)      * (y1 - y2)) / 2;    r = 50 >= r ? 50 : r;    Paint paint = new Paint();    paint.setColor(Color.BLUE);    canvas.drawCircle(x1, y1, r, paint);   }  } }