将JLabel置于JLabel之上，其中包含图像 [英] Place JLabel on top of JLabel with image in

问题描述

我很确定之前已经问过这个问题，但是我的情况略有不同，因为我试图将JLabel置于JLabel作为背景的顶部，我希望使用JLabel显示更改的数字和数字需要在背景上显示，但我有点摇摆n00b，提前谢谢，Jonathan

解决方案

完全理解您的要求，如果您只需要在背景图像上显示文字，最好将标签放在能够绘制背景的自定义面板上。

你可以获得布局管理器的好处而没有乱七八糟的东西。

我从一个读取低谷开始执行自定义绘画和 Graphics2D Trail 。

如果这似乎令人生畏， JLabel 实际上是一种 Container ，这意味着它实际上可以包含其他组件。 / p>

示例

背景窗格...

 公共类PaintPane扩展JPanel {
 
私有图像背景; 
 
 public PaintPane（图片图片）{
 //这只是一个例子，我更喜欢使用setter / getters 
 //并且还需要提供对齐选项;）
 background = image; 
} 
 
 @Override 
 public Dimension getPreferredSize（）{
 return background == null？ new Dimension（0,0）：new Dimension（background.getWidth（this），background.getHeight（this））; 
} 
 
 @Override 
 protected void paintComponent（Graphics g）{
 
 super.paintComponent（g）; 
 
 if（background！= null）{
 Insets insets = getInsets（）; 
 
 int width = getWidth（） -  1  - （insets.left + insets.right）; 
 int height = getHeight（） -  1  - （insets.top + insets.bottom）; 
 
 int x =（width  -  background.getWidth（this））/ 2; 
 int y =（height  -  background.getHeight（this））/ 2; 
 
 g.drawImage（background，x，y，this）; 
} 
 
} 
 
} 
  

使用...构建

  public TestLayoutOverlay（）抛出IOException {//扩展JFrame ... 
 
 setTitle（test）; 
 setLayout（new GridBagLayout（））; 
 setDefaultCloseOperation（EXIT_ON_CLOSE）; 
 
 PaintPane pane = new PaintPane（ImageIO.read（new File（fire.jpg）））; 
 pane.setLayout（new BorderLayout（））; 
 add（pane）; 
 
 JLabel label = new JLabel（我着火了）; 
 label.setFont（label.getFont（）。deriveFont（Font.BOLD，48））; 
 label.setForeground（Color.WHITE）; 
 label.setHorizo​​ntalAlignment（JLabel.CENTER）; 
 pane.add（label）; 
 
 pack（）; 
 setLocationRelativeTo（null）; 
 setVisible（true）; 
 
} 
  

只是为了表明我没有偏见;） ，使用标签的示例......

  public TestLayoutOverlay（）{
 
 setTitle（test ）; 
 setLayout（new GridBagLayout（））; 
 setDefaultCloseOperation（EXIT_ON_CLOSE）; 
 
 JLabel background = new JLabel（new ImageIcon（fire.jpg））; 
 background.setLayout（new BorderLayout（））; 
 add（背景）; 
 
 JLabel label = new JLabel（我着火了）; 
 label.setFont（label.getFont（）。deriveFont（Font.BOLD，48））; 
 label.setForeground（Color.WHITE）; 
 label.setHorizo​​ntalAlignment（JLabel.CENTER）; 
 background.add（label）; 
 
 pack（）; 
 setLocationRelativeTo（null）; 
 setVisible（true）; 
 
} 
  

I am pretty sure that this question has been asked before, but my case is slightly different as in i am trying to place a JLabel on top of a JLabel acting as a background, I want to display changing numbers using the JLabels and the numbers need to display over the background, however i am a bit of a swing n00b, thanks in advance, Jonathan

解决方案

Without fully appreciating your requirements, if you simply need to display text over a background image, you'd be better off placing the label on top a custom panel which is capable of painting your background.

You get the benefit of a layout manager without the mess.

I'd start by having a read trough Performing Custom Painting and Graphics2D Trail.

If that seems to daunting, JLabel is actually a type of Container, meaning it can actually 'contain' other components.

EXAMPLE

Background pane...

public class PaintPane extends JPanel {

    private Image background;

    public PaintPane(Image image) {     
        // This is just an example, I'd prefer to use setters/getters
        // and would also need to provide alignment options ;)
        background = image;            
    }

    @Override
    public Dimension getPreferredSize() {
        return background == null ? new Dimension(0, 0) : new Dimension(background.getWidth(this), background.getHeight(this));            
    }

    @Override
    protected void paintComponent(Graphics g) {

        super.paintComponent(g);

        if (background != null) {                
            Insets insets = getInsets();

            int width = getWidth() - 1 - (insets.left + insets.right);
            int height = getHeight() - 1 - (insets.top + insets.bottom);

            int x = (width - background.getWidth(this)) / 2;
            int y = (height - background.getHeight(this)) / 2;

            g.drawImage(background, x, y, this);                
        }

    }

}

Constructed with...

public TestLayoutOverlay() throws IOException { // Extends JFrame...

    setTitle("test");
    setLayout(new GridBagLayout());
    setDefaultCloseOperation(EXIT_ON_CLOSE);

    PaintPane pane = new PaintPane(ImageIO.read(new File("fire.jpg")));
    pane.setLayout(new BorderLayout());
    add(pane);

    JLabel label = new JLabel("I'm on fire");
    label.setFont(label.getFont().deriveFont(Font.BOLD, 48));
    label.setForeground(Color.WHITE);
    label.setHorizontalAlignment(JLabel.CENTER);
    pane.add(label);

    pack();
    setLocationRelativeTo(null);
    setVisible(true);

}

And just to show that I'm not bias ;), an example using labels...

public TestLayoutOverlay() {

    setTitle("test");
    setLayout(new GridBagLayout());
    setDefaultCloseOperation(EXIT_ON_CLOSE);

    JLabel background = new JLabel(new ImageIcon("fire.jpg"));
    background.setLayout(new BorderLayout());
    add(background);

    JLabel label = new JLabel("I'm on fire");
    label.setFont(label.getFont().deriveFont(Font.BOLD, 48));
    label.setForeground(Color.WHITE);
    label.setHorizontalAlignment(JLabel.CENTER);
    background.add(label);

    pack();
    setLocationRelativeTo(null);
    setVisible(true);

}

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