碰撞检测处理，刷新代码：public void update(Graphics g) { if(offScreenImage == null) { offScreenImage = this.createImage(GAME_WIDTH, GAME_HEIGHT); } Graphics gOffScreen = offScreenImage.getGraphics(); Color c = gOffScreen.getColor(); gOffScreen.setColor(Color.GREEN); gOffScreen.fillRect(0, 0, GAM