android自己写的类似刻度尺的东西(2)

        private float initx = 0; 
        @Override 
        public boolean onTouch(View v, MotionEvent event) { 
            switch(event.getAction()){ 
                case MotionEvent.ACTION_DOWN: 
                    initx = event.getX(); 
                    break; 
                case MotionEvent.ACTION_MOVE: 
                    float lastx = event.getX(); 
                    if(lastx > initx + 5){ 
                        kedu.draw(1); 
                        initx = lastx; 
                    }else if(lastx < initx -5){ 
                        kedu.draw(-1); 
                        initx = lastx; 
                    } 
                    break; 
            } 
            return true; 
        } 
    }; 
     
    class KeduView extends SurfaceView implements SurfaceHolder.Callback, Runnable{ 
         
        private SurfaceHolder mSurfaceHolder = null;   
        private Canvas canvas; 
        //画布背景 
        private Bitmap background;