draw on surfaceview onDraw

gistfile1.java

         @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
            canvas.restoreToCount(1);
            canvas.clipRect(new Rect(0, 0, getWidth(), getHeight()));
            canvas.drawCircle(x, y, 10, paint);
            canvas.save();      
        }
        float x,y;
        @Override
        public boolean onTouchEvent(MotionEvent event) {
            x=event.getX();
            y=event.getY();
            invalidate();
            return true;
        }

canvas.drawCircle(100, 100, 5, paint); //it is drawing fine
//while i am using like this :
canvas.drawCircle(x, y, 5, paint); //it's not drawing.x,y being some points on screen and they are floats.