Java Swing JLayeredPane未显示 [英] Java Swing JLayeredPane not showing up

问题描述

我似乎在JLayeredPane上遇到了一些重大问题.我有一个BorderLayout()窗格，我希望West-side元素彼此之间包含一些JLayeredPane，因此我可以在它们之间切换以显示正确的信息.

I seem to be having some major issues with JLayeredPane. I have a BorderLayout() pane, and I'd like for the West-side element to contain a few JLayeredPane's on top of each other, so I can switch between them to show the right information.

西窗格应为200像素宽，且应与整个窗口一样长.在我的示例代码中，我在JLayeredPanel中添加了两层，但是没有显示出来.它们应该在西窗格中.

The west pane should be 200 pixels wide and should be as long as the total window is. In my sample code I have added two layers to the JLayeredPanel, but they don't show up. They should be in the west pane.

这是我的代码:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;

public class Main {
    private static JFrame mainFrame = new JFrame();
    private static JPanel mainPane = new JPanel();
    public Main(){}

    public static void initGui(){
        JLayeredPane westPanel = new JLayeredPane();
        westPanel.setPreferredSize(new Dimension(200,0));
        westPanel.setBackground(Color.blue);

        JPanel layerOne = new JPanel();
        layerOne.add(new JLabel("This is layer 1"));
        westPanel.add(layerOne, new Integer(0), 0);

        JPanel layerTwo = new JPanel();
        layerTwo.add(new JLabel("This si layer 2"));
        westPanel.add(layerTwo, new Integer(1), 0);

        JPanel centerPanel = new JPanel();
        centerPanel.setBackground(Color.yellow);

        JPanel eastPanel = new JPanel();
        eastPanel.setPreferredSize(new Dimension(200,0));
        eastPanel.setBackground(Color.red);

        mainPane = new JPanel(new BorderLayout());
        mainPane.add(westPanel, BorderLayout.WEST);
        mainPane.add(centerPanel, BorderLayout.CENTER);
        mainPane.add(eastPanel, BorderLayout.EAST);

        mainFrame = new JFrame("Learning to use JLayeredPane");
        mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        mainFrame.setBounds(200, 200, 800, 500);
        mainFrame.setContentPane(mainPane);
        mainFrame.setVisible(true);
    }

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

这将导致以下结果:

What this results in:

推荐答案

JLayeredPane使用空布局，因此您有责任说明添加到其中的所有组件的大小和位置.如果不是，它们将默认为[0，0] 的位置，并且的大小为[0，0].

JLayeredPane uses a null layout and so you are responsible for stating the size and location of all components added to it. If not they will default to a location of [0, 0] and a size of [0, 0].

这篇关于Java Swing JLayeredPane未显示的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！