如何从另一个类更改JPanel? [英] How can I change the JPanel from another Class?

问题描述

我是Java新手，并且遇到以下问题:

我创建了一个JFrame，并且希望在单击JButton时更改JPanel.几乎可以正常工作.唯一的问题是程序创建了一个新窗口，然后有两个窗口.一个与第一个JPanel，另一个与第二个JPanel. 这是我当前的代码:

I created a JFrame and I want the JPanel to change when clicking a JButton. That does almost work.The only problem is that the program creates a new window and then there are two windows. One with the first JPanel and one with the second JPanel. Here is my current code:

头等舱:

public class Program {

    public static void main (String [] args) {

        new window(new panel1());

    }
}

第二类:

import java.awt.Toolkit;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Window extends JFrame {

    private static final long serialVersionUID = 1L;

    Window(JPanel panel) {

        setLocation((int) Toolkit.getDefaultToolkit().getScreenSize().getWidth() / 2 - 200,
                    (int) Toolkit.getDefaultToolkit().getScreenSize().getHeight() / 2 - 100);
        setSize(400, 200);
        setTitle("test");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setResizable(false);
        setContentPane(panel);
        setVisible(true);

    }
}

第三类:

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JPanel;

public class Panel1 extends JPanel {

    private final long serialVersionUID = 1L;

    Panel1() {

        JButton nextPanelButton = new JButton("click here");

        add(nextPanelButton);

        ActionListener changePanel = new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent event) {
                new window(new panel2());
            }
        };
        nextPanelButton.addActionListener(changePanel);

    }
}

第四节课:

public class Panel2 extends JPanel {

    private static final long serialVersionUID = 1L;

    Panel2() {

        JLabel text = new JLabel("You pressed the Button!");

        add(text);

    }
}

但是我只想在不打开新窗口的情况下更改JPanel.有办法吗?

提前谢谢！

推荐答案

这是一个演示

import javax.swing.*;

public class Main {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            new MainFrame("Title").setVisible(true);
        });
    }
}

MainFrame.java

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

public class MainFrame extends JFrame {
    private JPanel viewPanel;

    public MainFrame(String title) {
        super(title);
        createGUI();
    }

    private void createGUI() {
        setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        setLayout(new BorderLayout());
        setMinimumSize(new Dimension(600, 480));

        viewPanel = new JPanel(new BorderLayout());
        add(viewPanel, BorderLayout.CENTER);

        showView(new View1(this));
        pack();
   }

   public void showView(JPanel panel) {
        viewPanel.removeAll();
        viewPanel.add(panel, BorderLayout.CENTER);
        viewPanel.revalidate();
        viewPanel.repaint();
   }
}

View1.java

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

public class View1 extends JPanel {
    final private MainFrame owner;

    public View1(MainFrame owner) {
        super();

        this.owner = owner;
        createGUI();
    }

    private void createGUI() {
        setLayout(new FlowLayout());
        add(new JLabel("View 1"));

        JButton button = new JButton("Show View 2");
        button.addActionListener(event -> {
            SwingUtilities.invokeLater(() -> owner.showView(new View2(owner)));
        });

        add(button);
    }
}

View2.java

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

public class View2 extends JPanel {
    final private MainFrame owner;

    public View2(MainFrame owner) {
        super();

        this.owner = owner;
        createGUI();
    }

    private void createGUI() {
        setLayout(new FlowLayout());
        add(new JLabel("View 2"));

        JButton button = new JButton("Show View 1");
        button.addActionListener(event -> {
            SwingUtilities.invokeLater(() -> owner.showView(new View1(owner)));

        });

        add(button);
    }
}

这篇关于如何从另一个类更改JPanel?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！