框架中有多个JPanel/具有背景图像，而另一层具有顶部组件 [英] More than one JPanel in a Frame / having a brackground Image and another Layer with Components on the top

问题描述

我有一个带有JPanel的JFrame，其中有一个带有ImageIcon()的JLabel.一切运行正常，问题是我现在想向JFrame中添加另一个JPanel和其他所有东西，例如按钮等.但是它仍然在顶部显示背景图像，而在第二个JPanel中什么也没有显示.

I've got a JFrame with a JPanel in which there is a JLabel with an ImageIcon(). Everything's working perfectly, problem is i now want to add another JPanel with all the other stuff like buttons and so on to the JFrame. But it still shows the background Image on top and nothing with the second JPanel.

有人可以帮助我吗? 这是我的代码的一部分:

Can someone help me? Here is an extract of my code:

JFrame window = new JFrame("Http Download");


/*
 * Background Section
 */
JPanel panel1 = new JPanel();

JLabel lbl1 = new JLabel();


/*
 * Component Section
 */
JPanel panel2 = new JPanel();

JLabel lbl2 = new JLabel();


/*
 * Dimension Section
 */
Dimension windowSize = new Dimension(800, 600);
Dimension screen = Toolkit.getDefaultToolkit().getScreenSize();

public HTTPDownloadGUI() {

    window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    panel1.setLayout(null);
    panel1.setSize(windowSize);
    panel1.setOpaque(false);

    panel2.setLayout(null);
    panel2.setSize(windowSize);
    panel2.setOpaque(false);

    lbl1.setSize(windowSize);
    lbl1.setLocation(0, 0);
    lbl1.setIcon(new ImageIcon(getClass().getResource("bg1.png")));
    panel1.add(lbl1);

    lbl2.setBounds(0, 0, 100, 100);
    //lbl2.setIcon(new ImageIcon(getClass().getResource("bg2.png")));
    lbl2.setBackground(Color.GREEN);
    panel2.add(lbl2);

    panel1.add(panel2);

    window.add(panel1);

    int X = (screen.width / 2) - (windowSize.width / 2);
    int Y = (screen.height / 2) - (windowSize.height / 2);

    window.setBounds(X,Y , windowSize.width, windowSize.height);
    window.setVisible(true);

}

推荐答案

1. 避免使用空布局，这会带来更多麻烦，而不是值得
2. 将框架的布局设置为BorderLayout
3. 将标签添加到框架
4. 将标签布局设置为BorderLayout
5. 创建您的面板并将其不透明属性设置为false
6. 按常规添加其他组件
7. 将面板添加到标签

1. Avoid null layouts, here more trouble then they are worth
2. Set the frame a layout to BorderLayout
3. Add the label to the frame
4. Set the labels layout to BorderLayout
5. Create you panel and set it's opaque property to false
6. Add the other components to as per normal
7. Add the panel to the label

结帐

• 将图像作为背景在扩展的JFrame上是否存在任何问题?
• 将JLabel放在JLabel之上
中的图片

• Are there any issues with placing image as background on an extended JFrame?
• Place JLabel on top of JLabel with image in

例如

更新示例

• panel1是主要背景...
• 将panel1的布局设置为BorderLayout
• 将lbl1添加到panel1
• 将lbl1的布局设置为BorderLayout
• 将panel2的布局设置为您要使用的布局...
• 将panel2的不透明度属性设置为false(panel2.setOpacity(false))
• 将lbl2添加到panel2
• 将panel2添加到lbl1
• 在每个所需的内容中添加panel1.

• panel1 is the main background...
• Set panel1's layout to BorderLayout
• Add lbl1 to panel1
• Set lbl1's layout to BorderLayout
• Set panel2's layout to what ever you want to use...
• Set panel2's opacity property to false (panel2.setOpacity(false))
• Add lbl2 to panel2
• Add panel2 to lbl1
• Add panel1 to what every you want.

public class TestLayout17 {

    public static void main(String[] args) {
        new TestLayout17();
    }

    public TestLayout17() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        /*
         * Background Section
         */
        JPanel panel1 = new JPanel();
        JLabel lbl1 = new JLabel();
        /*
         * Component Section
         */
        JPanel panel2 = new JPanel();
        JLabel lbl2 = new JLabel();
        /*
         * Dimension Section
         */
        Dimension windowSize = new Dimension(800, 600);
        Dimension screen = Toolkit.getDefaultToolkit().getScreenSize();

        public TestPane() {

            setLayout(new BorderLayout());

            panel1.setLayout(new BorderLayout());

            lbl1.setLayout(new BorderLayout());
            URL url = getClass().getResource("/bg1.gif");
            System.out.println(url);
            try {
                BufferedImage image = ImageIO.read(url);
                Image smaller = image.getScaledInstance(-1, image.getHeight() / 2, Image.SCALE_SMOOTH);
                lbl1.setIcon(new ImageIcon(smaller));
            } catch (Exception e) {
                e.printStackTrace();
            }
//            lbl1.setIcon(new ImageIcon(url));
            panel1.add(lbl1);

            add(panel1);

            panel2.setLayout(new GridBagLayout());
            panel2.setOpaque(false);

            lbl2.setBorder(new EmptyBorder(8, 8, 8, 8));
            lbl2.setBackground(Color.GREEN);
            lbl2.setText("Say hello");;
            lbl2.setOpaque(true);
            panel2.add(lbl2);

            lbl1.add(panel2);

        }
    }
}

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