java - JFrame重画图像闪烁

Question

我在使用 super.paintComponents(g); 命令时遇到问题更新 JFrame 时。我遇到的问题是我正在加载的图像在代码运行时闪烁。我非常确定代码是双缓冲的，并且没有在网上找到任何有用的资源来解决这个问题。这是我的第一个问题，所以请容忍任何格式错误。

这是我的完整代码(下面是片段):

public class GAME extends JFrame implements KeyListener, MouseMotionListener {
int mouseX, mouseY;

public static ArrayList<Images> images = new ArrayList<Images>();
public static String lastKeyPressed = null;

public GAME() {
    this.addMouseMotionListener(this);
    this.addKeyListener(this);
}

public void mouseDragged(MouseEvent e) {
    mouseX = e.getX();
    mouseY = e.getY();
}

public void mouseMoved(MouseEvent e) {
    mouseX = e.getX();
    mouseY = e.getY();
}

public void keyPressed(KeyEvent e) {
    if (e.getKeyCode() == e.VK_LEFT) {
        lastKeyPressed = "LEFT";
    } else if (e.getKeyCode() == e.VK_RIGHT) {
        lastKeyPressed = "RIGHT";
    } else if (e.getKeyCode() == e.VK_UP) {
        lastKeyPressed = "UP";
    } else if (e.getKeyCode() == e.VK_DOWN) {
        lastKeyPressed = "DOWN";
    }
}

public void keyReleased(KeyEvent e) {

}

public void keyTyped(KeyEvent e) {

}

@Override
public void paint(Graphics g) {
    super.paintComponents(g);
    for (int i = 0; i < images.size(); i++) {
        g.drawImage(images.get(i).img, images.get(i).xpos, images.get(i).ypos, null);
    }
}

public static void main(String[] args) throws IOException, InterruptedException {
    GAME frame = new GAME();
    Dimension dim = new Dimension(800, 600);
    frame.setPreferredSize(dim);
    frame.setSize(dim);
    frame.setResizable(false);
    frame.setTitle("GAME");
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
    Images test = new Images("unnamed.png");
    images.add(test);
    while (true) {
        if (lastKeyPressed == "LEFT") {
            test.xpos -= 5;
            lastKeyPressed = null;
        } else if (lastKeyPressed == "RIGHT") {
            test.xpos += 5;
            lastKeyPressed = null;
        } else if (lastKeyPressed == "UP") {
            test.ypos -= 5;
            lastKeyPressed = null;
        } else if (lastKeyPressed == "DOWN") {
            test.ypos += 5;
            lastKeyPressed = null;
        }
        frame.repaint();
        Thread.sleep(100);
    }
}

}

这是图像类:

public class Images {

String name;
BufferedImage img;
int xpos;
int ypos;

public Images (String Name) throws IOException{
    name = Name;
    xpos = 40;
    ypos = 90;
    System.out.println(name);
    System.out.println("PATH: " + GAME.class.getResource(name));
    URL file = getClass().getClassLoader().getResource(name);
    img = ImageIO.read(file);
}
}

您可能只想看到以下内容:

我的绘画方法:

@Override
public void paint(Graphics g) {
    super.paintComponents(g);
    for (int i = 0; i < images.size(); i++) {
        g.drawImage(images.get(i).img, images.get(i).xpos, images.get(i).ypos, null);
    }
}

以及运行游戏的主类中的代码块:

Images test = new Images("unnamed.png");
    images.add(test);
    while (true) {
        if (lastKeyPressed == "LEFT") {
            test.xpos -= 5;
            lastKeyPressed = null;
        } else if (lastKeyPressed == "RIGHT") {
            test.xpos += 5;
            lastKeyPressed = null;
        } else if (lastKeyPressed == "UP") {
            test.ypos -= 5;
            lastKeyPressed = null;
        } else if (lastKeyPressed == "DOWN") {
            test.ypos += 5;
            lastKeyPressed = null;
        }
        frame.repaint();
        Thread.sleep(100);
    }

(我添加了 Thread.sleep，因为它似乎降低了闪烁发生的速率)

这是正在发生的事情的 gif(我刚刚使用了第一个 Google 结果作为图像的“测试”): http://i.imgur.com/WjLCSvu.gif?1

我感谢任何帮助和一般建议来改进我的代码。谢谢。

Answer 1

不要覆盖顶级容器的paint，例如JFrame，它们没有双缓冲，而是使用JPanel并覆盖其paintComponent 方法。 JPanel 默认情况下是双缓冲的。

然后，将面板添加到您想要的任何容器

在进行任何自定义绘画之前，不要忘记调用它的 super 方法 (super.paintComponent)。

仔细看看Painting in AWT and Swing和 Performing Custom Painting有关 Swing 中绘画工作原理的更多详细信息

这只是您不应该(从 JFrame 扩展并)覆盖顶级容器的 paint 的原因之一，请看一下

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• Graphics rendering in title bar
• Java JFrame .setSize(x, y) not working?
• How to get the EXACT middle of a screen, even when re-sized

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