在具有卡片布局的 JPanel 中的两个 JPanel 之间交换

Question

我正在尝试让两个 jpanels 通过那些 SPECIFIC 面板上的按钮进行交换，我不希望两个面板上的通用按钮像普通卡片布局一样在两个面板上重复使用。我尝试在主面板上使用一个名为 'add' 的按钮指向下一页，并在下一页上使用一个名为 'back' 的按钮指向主面板。但是由于某种原因它不起作用。我不希望 JFrame 上有两个 JPanel，因为稍后我会将 JPanel 添加到选项卡式窗格中。这是我已经拥有的：

控制器：

import java.awt.CardLayout;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class Controller extends JPanel {

    private static Controller instance = new Controller();

    JPanel cards;
    Main mainPanel;
    NextPage nextPage;

    public Controller() {
        setLayout(new BorderLayout());
        setSize(810, 510);
        cards = new JPanel(new CardLayout());

        mainPanel = new Main();
        nextPage = new NextPage();
        cards.add(mainPanel, "Main");
        cards.add(nextPage, "Next");
        add(cards);
        setVisible(true);
    }

    private static void createAndShowGUI() {
        JFrame frame = new JFrame("MainPanel");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Controller con = new Controller();
        frame.getContentPane().add(con);
        frame.setSize(800, 600);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }


    public void changeCard(String card) {
        CardLayout cl = (CardLayout) (cards.getLayout());
        cl.show(cards, card);
    }

    public static Controller getInstance() {
        return instance;
    }
}

主要：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.util.*;

public class Main extends JPanel implements ActionListener {

    private JButton search, add, delete;
    private JTextField textField;

    public Main() {

        search = new JButton("Search");
        add = new JButton("Add");
        delete = new JButton("Delete");
        textField = new JTextField(20);
        add.addActionListener(this);
        delete.addActionListener(this);
        setLayout(new BorderLayout());
        JPanel top = new JPanel();
        top.add(search);
        add(top, BorderLayout.NORTH);
        JPanel bottom = new JPanel();
        bottom.add(add);
        bottom.add(delete);
        add(bottom, BorderLayout.SOUTH);
        setVisible(true);
        setSize(400, 500);
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == add) {
            Controller.getInstance().changeCard("Next");
        } else if (e.getSource() == delete) {
           System.out.println("do something");
        }
    }

}

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.util.*;

public class NextPage extends JPanel implements ActionListener {

    private JButton back;
    private JTextField textField;

    public NextPage() {
        back = new JButton("Back");
        textField = new JTextField(20);
        back.addActionListener(this);
        setLayout(new BorderLayout());
        add(back);
        setVisible(true);
        setSize(400, 500);
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == back) {
            Controller.getInstance().changeCard("Next");
        }

    }
}

Answer 1

像这样更改您的Controller：

private static Controller instance;

...

private static void createAndShowGUI() {
    JFrame frame = new JFrame("MainPanel");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    instance = new Controller();
    frame.getContentPane().add(instance);
    frame.setSize(800, 600);
    frame.setVisible(true);
}

您实际上在 Controller 的一个实例上创建了所有内容并展示了它，但使用另一个实例来管理您的事件。对 Controller 构造函数的多次调用应该敲响了警钟，因为您只想要一个 Controller.

在具有卡片布局的 JPanel 中的两个 JPanel 之间交换

Swapping between two JPanels in a JPanel with card layout

java

swing

layout-manager

cardlayout