Question

我正在尝试创建程序，您可以按下第一页上的其中一个按钮，它将打开更多按钮和标签等。但我不知道如何制作它，以便当按下按钮时它会显示其他按钮和标签。

代码是

public class Japp extends JApplet implements ActionListener{

    private JPanel panel1= new JPanel();
    private JPanel panel2= new JPanel();

    JPanel container = new JPanel();
    //container.setLayout(new BoxLayout(container, BoxLayout.X_AXIS));

    JButton reg = new JButton ("Register");
    JButton log = new JButton ("Login");

    JLabel regusrlbl = new JLabel ("Enter Username");
    JLabel regpwdlbl = new JLabel ("Enter Password");
    JLabel regpwdconlbl = new JLabel ("Confirm Username");
    JTextField regusr = new JTextField("");
    JTextField regpwd = new JTextField("");
    JTextField regpwdcon = new JTextField("");
    JButton create = new JButton("Create");

    JLabel logusrlbl = new JLabel ("Enter Username");
    JLabel logpwdlbl = new JLabel ("Enter Password");
    JTextField logusr = new JTextField("");
    JTextField logpwd = new JTextField("");
    JButton login = new JButton("Login");

    public void init(){
    setLayout(null); 
    add(reg).setBounds(50,100,100,30);
    add(log).setBounds(150,100,100,30);

    }
    @SuppressWarnings("deprecation")

    public void actionPerformed(ActionEvent e) {
        JButton source = (JButton)e.getSource();
        if (source.getLabel()=="reg"){

        // TODO Auto-generated method stub
            remove(reg);
            remove(log);
            add(regusrlbl).setBounds(20,20, 150,50);
            add(regusr).setBounds(20,50,100,30);
            add(regpwdlbl).setBounds(200,20,150,50);
            add(regpwd).setBounds(200,50,100,30);
            add(regpwdconlbl).setBounds(195,80,150,30);
            add(regpwdcon).setBounds(200,110,100,30);
            add(create).setBounds(110,140,100,30);
        // setup all the context...
        }   
        else if(source.getLabel()=="log"){
            remove(reg);
            remove(log);
            add(logusrlbl).setBounds(20,20, 150,50);
            add(logusr).setBounds(20,50,100,30);
            add(logpwdlbl).setBounds(200,20,150,50);
            add(logpwd).setBounds(200,50,100,30);
            add(login).setBounds(110,140,100,30);
        }
    }   
}

Answer 1

避免null布局。您无法控制字体在不同系统上的呈现方式，因此除非您打算仅在为其开发的计算机上运行应用程序，否则请避免使用null布局。学习如何使用和理解如何使用不同的布局管理器来实现您的目标。
使用CardLayout，这就是它的目的，让您轻松更改可见组件组。

这将要求您将应用程序分解为单独的组件/面板，但是您可以独立地关注每个部分的个性化需求

使用示例更新

enter image description here

import java.awt.CardLayout;
import java.awt.Container;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JSeparator;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class TestCardLayout100 {

    public static void main(String[] args) {
        new TestCardLayout100();
    }

    public TestCardLayout100() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                LoginPane loginPane = new LoginPane();
                RegisterPane registerPane = new RegisterPane();

                JPanel startPane = new JPanel(new GridBagLayout());
                GridBagConstraints gbc = new GridBagConstraints();
                gbc.gridx = 0;
                gbc.gridy = 0;
                startPane.add(loginPane, gbc);
                gbc.gridx = 2;
                startPane.add(registerPane, gbc);
                gbc.gridx = 1;
                gbc.fill = GridBagConstraints.VERTICAL;
                startPane.add(new JSeparator(JSeparator.VERTICAL), gbc);

                JPanel loggedInPane = new JPanel(new GridBagLayout());
                loggedInPane.add(new JLabel("Logged In..."));

                JPanel registeredPane = new JPanel(new GridBagLayout());
                registeredPane.add(new JLabel("Registered..."));

                final JFrame frame = new JFrame("Testing");
                final CardLayout cardLayout = new CardLayout();

                loginPane.addActionListener(new ActionListener() {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        cardLayout.show(frame.getContentPane(), "loggedIn");
                    }
                });
                registerPane.addActionListener(new ActionListener() {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        cardLayout.show(frame.getContentPane(), "registered");
                    }
                });

                Container contentPane = frame.getContentPane();
                contentPane.setLayout(cardLayout);
                contentPane.add(startPane, "startPane");
                contentPane.add(loggedInPane, "loggedIn");
                contentPane.add(registeredPane, "registered");

                cardLayout.show(contentPane, "startPane");

                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class LoginPane extends JPanel {

        private final JLabel logusrlbl = new JLabel("Enter Username");
        private final JLabel logpwdlbl = new JLabel("Enter Password");
        private final JTextField logusr = new JTextField(10);
        private final JTextField logpwd = new JPasswordField(10);
        private final JButton login = new JButton("Login");

        public LoginPane() {
            setLayout(new GridBagLayout());

            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridx = 0;
            gbc.gridy = 0;
            gbc.gridwidth = GridBagConstraints.REMAINDER;
            add(new JLabel("Login"), gbc);

            gbc.gridy++;
            gbc.gridwidth = 1;
            add(logusrlbl, gbc);
            gbc.gridy++;
            add(logpwdlbl, gbc);

            gbc.gridx++;
            gbc.weightx = 1;
            gbc.fill = GridBagConstraints.HORIZONTAL;
            gbc.gridy = 1;

            add(logusr, gbc);
            gbc.gridy++;
            add(logpwd, gbc);

            gbc.gridx = 0;
            gbc.gridy++;
            gbc.anchor = GridBagConstraints.EAST;
            gbc.gridwidth = GridBagConstraints.REMAINDER;
            gbc.fill = GridBagConstraints.NONE;
            add(login, gbc);

        }

        public void addActionListener(ActionListener listener) {
            login.addActionListener(listener);
        }

    }

    public class RegisterPane extends JPanel {

        private final JLabel logusrlbl = new JLabel("Enter Username");
        private final JLabel logpwdlbl = new JLabel("Enter Password");
        private final JTextField logusr = new JTextField(10);
        private final JTextField logpwd = new JPasswordField(10);
        private final JButton register = new JButton("Register");

        public RegisterPane() {
            setLayout(new GridBagLayout());

            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridx = 0;
            gbc.gridy = 0;
            gbc.gridwidth = GridBagConstraints.REMAINDER;
            add(new JLabel("Register"), gbc);

            gbc.gridy++;
            gbc.gridwidth = 1;
            add(logusrlbl, gbc);
            gbc.gridy++;
            add(logpwdlbl, gbc);

            gbc.gridx++;
            gbc.weightx = 1;
            gbc.fill = GridBagConstraints.HORIZONTAL;
            gbc.gridy = 1;

            add(logusr, gbc);
            gbc.gridy++;
            add(logpwd, gbc);

            gbc.gridx = 0;
            gbc.gridy++;
            gbc.anchor = GridBagConstraints.EAST;
            gbc.fill = GridBagConstraints.NONE;
            gbc.gridwidth = GridBagConstraints.REMAINDER;
            add(register, gbc);

        }

        public void addActionListener(ActionListener listener) {
            register.addActionListener(listener);
        }

    }

}

如何使按钮显示其他按钮和选项。

1 个答案: