Java .drawImage:如何“取消绘制"；或删除图片? [英] Java .drawImage : How do I "unDraw" or delete a image?

问题描述

我需要在程序运行时不断在不同位置重绘特定图像.因此，我设置了一个while循环，该循环应该在屏幕上移动图像，但是它只是一遍又一遍地重画图像.我究竟做错了什么?有没有办法在将新图像绘制到新位置之前将其删除?

I need a certain image to be redrawn at different locations constantly as the program runs. So I set up a while loop that should move an image across the screen, but it just redraws the image on top of itself over and over again. What am I doing wrong? Is there a way to delete the old image before drawing it in a new location?

        JFrame frame = buildFrame();

    final BufferedImage image = ImageIO.read(new File("BeachRoad_double_size.png"));

    JPanel pane = new JPanel() {
        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            int num = 0;
            boolean fluff = true;
            while (fluff == true) {
            num = num + 1;
            g.drawImage(image, num, 0, null);
            if (num == 105) {
                fluff = false;
            }
            }
        }
    };


    frame.add(pane);

推荐答案

您不能在paintComponent()方法中编写循环.该代码将执行得如此之快，以致只能在最终位置上绘制图像，在您的情况下，最终位置应为x位置105.

You can't code a loop in the paintComponent() method. The code will execute so fast that the image will only be painted in the final position, which in your case should be with an x position of 105.

相反，您需要使用Swing计时器每100毫秒左右安排一次动画.然后，当计时器触发时，您将更新x位置并在面板上调用repaint().阅读使用Swing计时器上的Swing教程，以获取更多信息.

Instead you need to use a Swing Timer to schedule the animation every 100 milliseconds or so. Then when the timer fires you update the x position and invoke repaint() on the panel. Read the Swing tutorial on Using Swing Timers for more information.

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