public class DrawActivity extends Activity {
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		dp=new DrawingPanel(this);
		setContentView(dp);

		mPaint = new Paint();
		mPaint.setDither(true);
		mPaint.setColor(0xFFFF0000);
		mPaint.setStyle(Paint.Style.STROKE);
		mPaint.setStrokeJoin(Paint.Join.ROUND);
		mPaint.setStrokeCap(Paint.Cap.ROUND);
		mPaint.setStrokeWidth(8);
}

	class DrawingPanel extends SurfaceView implements SurfaceHolder.Callback {
		// private DrawingThread _thread;
		public DrawingPanel(Context context) {

			super(context);
			System.out.println(" i'm in Drawing panel context");
			getHolder().addCallback(this);
			_thread = new DrawingThread(getHolder(), this);

		}

		public boolean onTouchEvent(MotionEvent event) {
			synchronized (_thread.getSurfaceHolder()) {

				if (event.getAction() == MotionEvent.ACTION_DOWN) {
					System.out.println("i'm in ACTION_DOWN ");


					path.addCircle(event.getX(), event.getY(), 2,
							Path.Direction.CCW);
					_graphics.add(path);
				}

				return true;
				}
		}

		public void onDraw(Canvas canvas) {
			canvas1=canvas;
			canvas.drawColor(Color.WHITE);
			if (onSelect == true) {
				onSelect = false;
				_graphics.clear();
			}
			for (Path path : _graphics) {
				canvas.drawPath(path, mPaint);
				}

			}


		@Override
		public void surfaceChanged(SurfaceHolder holder, int format, int width,
				int hight) {
			// TODO Auto-generated method stub
			}

		@Override
		public void surfaceCreated(SurfaceHolder holder) {
			// TODO Auto-generated method stub
			System.out.println(" I'M in surface created method method");
			_thread.setRunning(true);
			_thread.start();

		}

		@Override
		public void surfaceDestroyed(SurfaceHolder holder) {
			// TODO Auto-generated method stub
			// canvas.drawPath(path, mPaint);
			boolean retry = true;
			_thread.setRunning(false);
			while (retry) {
				try {
					_thread.join();
					retry = false;
					System.out.println(" I'M in surface DESTROYED method");
				} catch (InterruptedException e) {
					// we will try it again and again...
					}
				}
			}
		}

	class DrawingThread extends Thread {

		private boolean _run = false;
		public DrawingThread(SurfaceHolder surfaceHolder, DrawingPanel panel) {

			_surfaceHolder = surfaceHolder;
			_panel = panel;
		}

		public void setRunning(boolean run) {
			_run = run;
		}

		public SurfaceHolder getSurfaceHolder() {
			return _surfaceHolder;
		}

		@Override
		public void run() {

			//Point point = new Point();
			while (_run) {
				c = null;
				try {
					c = _surfaceHolder.lockCanvas(null);
					synchronized (_surfaceHolder) {
						_panel.onDraw(c);
						}
					}
				finally {
					// do this in a finally so that if an exception is thrown
					// during the above, we don't leave the Surface in an
					// inconsistent state
					if (c != null) {
						_surfaceHolder.unlockCanvasAndPost(c);
						}
					}
				}
			}
		}

	// TODO Auto-generated method stub
	public boolean onCreateOptionsMenu(Menu menu) {

		MenuInflater inflater = getMenuInflater();
		inflater.inflate(R.menu.menu1, menu);
		return true;
	}

	public boolean onOptionsItemSelected(MenuItem item) {
		switch (item.getItemId()) {
		case R.id.changeScreen:
		onSelect = true;  ----->this means i clear the screen first then want to made changes

//here i want to draw different to that canvas by calling this method
			changeScreen();

			break;
		}
		return true;
	}
private void changeScreen()
    {
Path path1=new Path();
 path1.addCircle(50, 60, 12,Path.Direction.CCW);
canvas1.drawPath(path1, mPaint);
}
}