drawimage的用法 java_Java .drawImage：如何“取消繪制”；或删除圖檔？

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);

解決方案

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.

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.