JPanel透明背景和显示元素 [英] JPanel transparent background and display elements

问题描述

我在JPanel中插入了背景图像 e，但是一些界面元素消失了.以下Java Swing元素不会出现:

I insert a background image into a JPanel but some interface elements disappear. The following Java Swing elements do not appear:

• label_titulo
• label_usuario
• label_password
• button_acceder

**您可以使图像透明还是元素不透明(setOpaque(false))，即使将其放在这些元素上对我也不起作用.

**Can you make the image transparent or that the elements are not opaque (setOpaque (false)), even putting it to those elements does not work for me.

为什么某些元素具有矩形将其封装为灰色?**

Why do some elements have rectangles encapsulating them in gray?**

代码:

public class InicioSesion extends javax.swing.JFrame{
    private Image imagenFondo;
    private URL fondo;

    public InicioSesion(){
        initComponents();

        try{
            fondo = this.getClass().getResource("fondo.jpg");
            imagenFondo = ImageIO.read(fondo);
        }catch(IOException ex){
            ex.printStackTrace();
            System.out.print("Imagen no cargada.");
        }
    }


    @Override
    public void paint(Graphics g){
        super.paint(g);
        g.drawImage(imagenFondo, 0, 0, getWidth(), getHeight(), this);
    }
}

加载"RUN"时，.java文件对我显示如下:

When loading "RUN" the .java file appears to me as follows:

最初的设计如下:

推荐答案

public void paint(Graphics g){
    super.paint(g);
    g.drawImage(imagenFondo, 0, 0, getWidth(), getHeight(), this);
}

不要覆盖paint().绘制方法负责绘制子组件.因此，您的代码会绘制子组件，然后在组件之上绘制图像.

Don't override paint(). The paint method is responsible for painting the child components. So your code paints the child components and then draws the image over top of the components.

相反，对于组件的自定义绘制，您可以覆盖JPanel的paintComponent()方法:

Instead, for custom painting of a component you override the paintComponent() method of a JPanel:

protected void paintComponent(Graphics g){
    super.paintComponent(g);
    g.drawImage(imagenFondo, 0, 0, getWidth(), getHeight(), this);
}

从深入了解绘制机制以获取更多信息.

从Custom Painting的Swing教程中阅读整个部分.解决方案是在JPanel上进行自定义绘制，然后将面板添加到框架中.

Read the entire section from the Swing tutorial on Custom Painting. The solution is to do the custom painting on a JPanel and then add the panel to the frame.

框架的内容窗格是JPanel.因此，您实际上将用绘制背景图像的自定义JPanel替换默认的内容窗格.将自定义面板的布局设置为BorderLayout，它将像默认内容窗格一样工作.

The content pane of a frame is a JPanel. So you will in effect be replacing the default content pane with your custom JPanel that paints the background image. Set the layout of your custom panel to a BorderLayout and it will work just like the default content pane.

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