我目前正在使用Eclipse(Luna,Win 8.1)进行一个简短的Java Swing项目。目的是显示包含菜单的框架。菜单具有不同的页面(主要,选项等),由带有按钮,标签等的JPanels实现。这些JPanel由CardLayout进行组织,以这种方式在调用CardLayout.show(..)方法之间进行切换不同的菜单页面。两天前我停止编程时,一切工作正常。但是,当我想在昨天早晨继续时,我的代码似乎完全忽略了CardLayout:将其他光标放在其位置上时,位于其他卡中的按钮将在第一张卡的背景中弹出。我试图连续17小时修复(搜索,使用备份等)该问题。问题仍然存在,现在我非常绝望= /。以下SSCCE显示了相同的行为(将鼠标移到左下角以查看“选项”卡的“后退”按钮弹出)。

package sscce;

import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class MainFrame extends JFrame {
    private CardLayout mainWindowLayout;
    // mainPanel will be used as the MainFrame's main unit to manage Components
    private JPanel mainPanel;

    // Constructor
    public MainFrame() {
        setTitle("sscce");
        setPreferredSize(new Dimension(800, 600));
        setResizable(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        getContentPane().setLayout(new BorderLayout());

        mainPanel = new JPanel();
        mainPanel.setPreferredSize(getSize());
        mainWindowLayout = new CardLayout();
        mainPanel.setLayout(mainWindowLayout);

        buildMainMenu();
        buildOptions();

        getContentPane().add(mainPanel);
        mainPanel.setVisible(true);
        // starting application it will "show" (container,
        // contentIdentifier(String))
        mainWindowLayout.show(mainPanel, "2");
        pack();
        setVisible(true);
    }// Constructor

    private void buildMainMenu() {
        JPanel panelMainMenu = new JPanel(new GridBagLayout());
        panelMainMenu.setBackground(Color.orange);

        // 1 Button (centered) to go to Options-Card
        JButton bnOptions = new JButton("Options");
        // Button Functionality
        bnOptions.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                mainWindowLayout.show(mainPanel, "2");
            }
        });
        panelMainMenu.add(bnOptions);
        panelMainMenu.setOpaque(true);
        // container content identifier(String)
        mainPanel.add(panelMainMenu, "1");
        panelMainMenu.setVisible(true);
    }// buildMainMenu

    private void buildOptions() {
        JPanel panelOptions = new JPanel();
        panelOptions.setLayout(new GridBagLayout());
        // standardized margins for all Elements:
        final Insets gbcInsets = new Insets(5, 5, 5, 5);
        panelOptions.setBackground(Color.white);

        JPanel fillerRight = new JPanel();
        JPanel fillerTop = new JPanel();
        JButton bnOptBack = new JButton("Back");

        bnOptBack.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                mainWindowLayout.show(mainPanel, "1");
            }
        });

        // add filler panels to keep button in position
        fillerRight.setBackground(Color.red);
        fillerRight.setOpaque(true);
        panelOptions.add(fillerRight, new GridBagConstraints(1, 1, 1, 2, 1, 0,
                GridBagConstraints.NORTH, GridBagConstraints.BOTH, gbcInsets,
                0, 0));
        fillerRight.setVisible(true);

        fillerTop.setBackground(Color.pink);
        fillerTop.setOpaque(true);
        panelOptions.add(fillerTop, new GridBagConstraints(0, 0, 2, 1, 0, 1,
                GridBagConstraints.NORTH, GridBagConstraints.BOTH, gbcInsets,
                0, 0));
        fillerTop.setVisible(true);

        // 1 Button in lower left hand corner, sends you back to MainMenu-card
        panelOptions.add(bnOptBack, new GridBagConstraints(0, 1, 1, 1, 0, 0,
                GridBagConstraints.NORTH, GridBagConstraints.BOTH, gbcInsets,
                0, 0));
        bnOptBack.setVisible(true);

        panelOptions.setOpaque(true);
        // container content identifier(String)
        mainPanel.add(panelOptions, "2");
        panelOptions.setVisible(true);
    }// buildOptions

    public static void main(String[] args) {
        MainFrame m = new MainFrame();
    }// main
}// MainFrame


任何帮助是极大的赞赏。
提前致谢 :)
编辑:我想您不需要太仔细地查看“ buildMainMenu”和“ buildOptions”方法,单个菜单页面的设置似乎可以正常工作。

最佳答案

当我注释掉以下两行时,它可以在我的机器上按预期工作

panelOptions.setVisible(true);




panelMainMenu.setVisible(true);


使用CardLayout时,只需添加组件并使用CardLayout#show决定显示哪个组件。首先调用setVisible似乎会导致问题(无论出于何种原因)。

确保在EDT上触发Swing代码也是一个好主意:

public static void main(String[] args) {

    EventQueue.invokeLater(new Runnable() {
      @Override
      public void run() {
        MainFrame m = new MainFrame();
      }
    });

10-08 18:10