java 将 JLabel 放在带有图像的 JLabel 顶部
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Place JLabel on top of JLabel with image in
提问by Excalibur
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
我很确定之前已经问过这个问题，但我的情况略有不同，因为我试图将 JLabel 放在作为背景的 JLabel 之上，我想使用 JLabels 显示不断变化的数字，并且需要的数字显示在背景上，但我有点摇摆不定，提前致谢，乔纳森
回答by MadProgrammer
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.
在不完全了解您的要求的情况下，如果您只需要在背景图像上显示文本，您最好将标签放在能够绘制背景的自定义面板的顶部。
You get the benefit of a layout manager without the mess.
您可以轻松获得布局管理器的好处。
I'd start by having a read trough Performing Custom Paintingand Graphics2D Trail.
我首先阅读Performing Custom Paintingand Graphics2D Trail。
If that seems to daunting, JLabelis actually a type of Container, meaning it can actually 'contain' other components.
如果这看起来令人生畏，JLabel实际上是一种Container，这意味着它实际上可以“包含”其他组件。
EXAMPLE
例子
Background pane...
背景窗格...
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...
用...建造
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...
只是为了表明我没有偏见;)，一个使用标签的例子......
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);
}
回答by Excalibur
At runtime:
在运行时：
- remove the label from its parent
- add a container, which supports layers
- add the 2x layer, but keep the Z order
- 从其父标签中删除标签
- 添加一个支持图层的容器
- 添加 2x 层，但保持 Z 顺序
Enjoy. (No full code given for copy-paste)
享受。（没有给出复制粘贴的完整代码）
回答by Victor Mukherjee
you can do that by this:
你可以这样做：
JLabel l1=new JLabel();
JLabel l2=new JLabel();
l1.add(l2, JLabel.NORTH);
