java将两个活动JPanel层叠在一起

2 年 Questions & Answers 261

我试图创建一个简单的动画，让游泳者沿着水下的路径。我有两个JPanel——一个是游泳运动员，一个是背景。两者都处于活动状态，游泳者正在移动四肢，背景中有鱼/障碍物需要更新

我试图把游泳者置于背景之上。我试图使用JLayeredPane，所以我创建了两个层并添加它们：

JLayeredPane lp = frame.getLayeredPane(); lp.setPreferredSize(new Dimension(650, 550)); underwaterScene.setSize(lp.getPreferredSize()); underwaterScene.setLocation(0,0); swimmer.setSize(lp.getPreferredSize()); swimmer.setLocation(0,0); swimmer.setOpaque(false); lp.add(underwaterScene, Integer.valueOf(1)); lp.add(swimmer, Integer.valueOf(2));

游泳者的paintComponent方法只是将游泳者画到正确的位置：

g.drawImage(swimmer.sprite, swimmer.x, swimmer.y, 150, 100, null);

目前，我只看到游泳层。如果我移除lp。添加（游泳者…打电话，然后我可以看到背景层，所以我知道它正在添加

我的问题是：为什么游泳者出现在背景之上时没有完全阻挡它

提前感谢您的帮助

# 1 楼答案

下面是一个有效的例子

此外，你可以在这里找到它的上下文： https://github.com/fzoli/RemoteControlCar/blob/master/desktop/BrowserTest/src/ConstrainVisibility.java#L58

public class ConstrainVisibility extends JPanel {

  protected static final String LS = System.getProperty("line.separator");
  protected static final int OFFSET_X = 150;
  protected static final int OFFSET_Y = 120;
  protected static final int WIDTH = 200;
  protected static final int HEIGHT = 200;

  public ConstrainVisibility() {
    super(new BorderLayout());
    JLayeredPane layeredPane = new JLayeredPane();
    layeredPane.setOpaque(true);
    layeredPane.setBackground(new Color(200, 200, 255));
    int layerIndex = 0;
    // A flash player

    // A swing panel
    JPanel swingPanel = new JPanel();
    swingPanel.setBorder(BorderFactory.createTitledBorder("Swing JPanel"));
    swingPanel.setBackground(Color.GREEN);
    swingPanel.setBounds(OFFSET_X * layerIndex, OFFSET_Y * layerIndex, WIDTH, HEIGHT);
    layeredPane.setLayer(swingPanel, layerIndex++);
    layeredPane.add(swingPanel);
    // A web browser
    JWebBrowser webBrowser = new JWebBrowser(JWebBrowser.constrainVisibility());
    webBrowser.setBarsVisible(false);
    webBrowser.setStatusBarVisible(true);
    webBrowser.setHTMLContent(
        "<html>" + LS +
        "  <body>" + LS +
        "    <h1>A web page</h1>" + LS +
        "    <p>A paragraph with a <a href=\"http://www.google.com\">link</a>.</p>" + LS +
        "  </body>" + LS +
        "</html>");
    webBrowser.setBounds(OFFSET_X * layerIndex, OFFSET_Y * layerIndex, WIDTH, HEIGHT);
    layeredPane.setLayer(webBrowser, layerIndex++);
    // A swing button
    JButton swingButton = new JButton("Swing JButton");
    swingButton.setBounds(OFFSET_X * layerIndex, OFFSET_Y * layerIndex, WIDTH, HEIGHT);
    layeredPane.setLayer(swingButton, layerIndex++);
    layeredPane.add(swingButton);
    layeredPane.add(webBrowser);
    layeredPane.setPreferredSize(new Dimension(WIDTH + OFFSET_X * (layerIndex - 1), HEIGHT + OFFSET_Y * (layerIndex - 1)));
    add(new JScrollPane(layeredPane), BorderLayout.CENTER);
  }

  /* Standard main method to try that test as a standalone application. */
  public static void main(String[] args) {
    UIUtils.setPreferredLookAndFeel();
    NativeInterface.open();
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        JFrame frame = new JFrame("DJ Native Swing Test");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(new ConstrainVisibility(), BorderLayout.CENTER);
        frame.setSize(800, 600);
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
      }
    });
    NativeInterface.runEventPump();
  }

}

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java将两个活动JPanel层叠在一起

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