Java，设置监听器，打开一个窗口，窗口中有个按钮，怎样在这按钮中再设置个监听器，打开另一个窗口？

Posted 2023-05-17

添加这个按钮的addActionListener(ActionListener l)监听;
button.addActionListener(new ActionListener()
public void actionPerformed(ActionEvent e)
// TODO Auto-generated method stub
new 另外窗口名称().setVisible(true);

); 参考技术A 你要打开的窗口里有按钮，总得要代码那按钮放到窗口上，那个时候设置监听不就好了。

java在线聊天项目 swt可视化窗口Design 登录框注册按钮点击改变窗口大小——出现注册面板 实现打开登录框时屏幕居中

登录框注册按钮点击改变窗口大小——出现注册面板 

首先用swt可视化设计登录窗口如下图：

此时窗口高度为578

没点击注册时高度为301（可自己定）

注意：注册用户的Jpanel 的border选择Title Border,title属性是“注册用户”

　　    布局Layout选择Absolute Layout

接着，对话框窗口设计好后，双击注册按钮，进行代码编辑，在注册按钮的监听代码中增加一个if判断，当等于301，就给改为窗口高度578，否则改为301

因为使用的是匿名内部类，不能直接使用this.关键字调用getHeight()方法和setHeight()方法，所以用LoginDialog.this.的方法进行调用

完整代码如下：

package com.swift;

import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.TitledBorder;

public class LoginDialog extends JDialog {

    private JPasswordField passwordField_2;
    private JPasswordField passwordField_1;
    private JTextField textField_2;
    private JTextField textField;
    public static void main(String args[]) {
        JFrame.setDefaultLookAndFeelDecorated(true);
        JDialog.setDefaultLookAndFeelDecorated(true);
        
        try {
            UIManager.setLookAndFeel("javax.swing.plaf.nimbus.NimbusLookAndFeel");
        } catch (ClassNotFoundException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        } catch (InstantiationException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        } catch (IllegalAccessException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        } catch (UnsupportedLookAndFeelException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        
        
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    LoginDialog dialog = new LoginDialog();
                    dialog.addWindowListener(new WindowAdapter() {
                        public void windowClosing(WindowEvent e) {
                            System.exit(0);
                        }
                    });
                    dialog.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }
    
    public LoginDialog() {
        super();
        setResizable(false);
        setTitle("在线聊天登录框");
        getContentPane().setLayout(null);
        setBounds(100, 100, 427, 301);//注册时高度为578，不注册是301

        final JButton button_1 = new JButton();
        button_1.setText("登录");
        button_1.setBounds(230, 222, 106, 36);
        getContentPane().add(button_1);

        final JTextField textField_1 = new JTextField();
        textField_1.setBounds(148, 90, 192, 42);
        getContentPane().add(textField_1);

        final JLabel label = new JLabel();
        label.setText("帐    号");
        label.setBounds(76, 102, 66, 18);
        getContentPane().add(label);

        final JLabel label_1 = new JLabel();
        label_1.setText("密    码");
        label_1.setBounds(76, 167, 66, 18);
        getContentPane().add(label_1);

        final JPasswordField passwordField = new JPasswordField();
        passwordField.setBounds(148, 155, 192, 42);
        getContentPane().add(passwordField);

        final JButton button = new JButton();
        button.addActionListener(new ActionListener() {
            public void actionPerformed(final ActionEvent e) {
                if(LoginDialog.this.getHeight()==301) {//使用LoginDialog.this.的方法调用，判断高度，前边有setResizable(false);
                    LoginDialog.this.setSize(427, 578);
                }else {
                    LoginDialog.this.setSize(427, 301);
                }
            }
        });
        button.setText("注册");
        button.setBounds(76, 222, 106, 36);
        getContentPane().add(button);

        final JPanel panel = new JPanel();
        panel.setLayout(null);
        panel.setBorder(new TitledBorder(null, "注册用户", TitledBorder.DEFAULT_JUSTIFICATION, TitledBorder.DEFAULT_POSITION, null, null));
        panel.setBounds(10, 278, 401, 226);
        getContentPane().add(panel);

        final JLabel label_2 = new JLabel();
        label_2.setBounds(44, 41, 65, 18);
        label_2.setText("手机号：");
        panel.add(label_2);

        textField = new JTextField();
        textField.setBounds(115, 35, 225, 30);
        panel.add(textField);

        final JButton button_2 = new JButton();
        button_2.setText("发送验证");
        button_2.setBounds(243, 75, 97, 30);
        panel.add(button_2);

        textField_2 = new JTextField();
        textField_2.setBounds(115, 104, 95, 30);
        panel.add(textField_2);

        final JLabel label_3 = new JLabel();
        label_3.setText("验证码：");
        label_3.setBounds(44, 110, 65, 18);
        panel.add(label_3);

        passwordField_1 = new JPasswordField();
        passwordField_1.setBounds(115, 143, 231, 30);
        panel.add(passwordField_1);

        passwordField_2 = new JPasswordField();
        passwordField_2.setBounds(115, 175, 231, 30);
        panel.add(passwordField_2);

        final JLabel label_4 = new JLabel();
        label_4.setText("密        码：");
        label_4.setBounds(44, 149, 65, 18);
        panel.add(label_4);

        final JLabel label_5 = new JLabel();
        label_5.setText("验证密码：");
        label_5.setBounds(44, 181, 65, 18);
        panel.add(label_5);

        final JButton button_3 = new JButton();
        button_3.setBounds(47, 510, 97, 30);
        getContentPane().add(button_3);
        button_3.setText("放弃");

        final JButton button_4 = new JButton();
        button_4.setBounds(262, 510, 97, 30);
        getContentPane().add(button_4);
        button_4.setText("注册用户");
    }
    
}

 

---

 

实现打开登录框时屏幕居中

因屏幕居中的功能，其他窗口也需要，所以见一个工具类

原理是获得屏幕的宽度和高度

分别减去对话框的宽度和高度

然后除以2

就是窗口居中的那个点——Point

首先，制作一个类com.swift.util.Center

里边有一个方法getPoint(int width,int height)

和一个包装的重载方法，方便调用

getPoint(Dimension d)

全部代码如下：

package com.swift.util;

import java.awt.Dimension;
import java.awt.Point;
import java.awt.Toolkit;

public class Center {
    public static Point getPoint(int width,int height) {
        Toolkit toolkit=Toolkit.getDefaultToolkit();//应该是单例
        int screenW=toolkit.getScreenSize().width;
        int screenH=toolkit.getScreenSize().height;
        int x=(screenW-width)/2;
        int y=(screenH-height)/2;
        Point p=new Point(x,y);
        return p;
    }
    //函数的重载，参数是包装类尺寸——Dimension
    public static Point getPoint(Dimension d) {
        Point p=getPoint(d.width,d.height);
        return p;
    }
}

使用居中的工具类

this.setLocation(Center.getPoint(this.getSize()));

在设置对话框宽度高度后，重新设置窗口位置

LoginDialog.this.setLocation(Center.getPoint(LoginDialog.this.getSize()));

匿名内部类中，当点击注册按钮，窗口被重新改变大小之后，也要不断改变窗口位置，内部类使用LoginDialog.this.

全部代码修改如下：

package com.swift;

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.TitledBorder;

import com.swift.util.Center;

public class LoginDialog extends JDialog {

    private JPasswordField passwordField_2;
    private JPasswordField passwordField_1;
    private JTextField textField_2;
    private JTextField textField;
    public static void main(String args[]) {
        JFrame.setDefaultLookAndFeelDecorated(true);
        JDialog.setDefaultLookAndFeelDecorated(true);
        
        try {
            UIManager.setLookAndFeel("javax.swing.plaf.nimbus.NimbusLookAndFeel");
        } catch (ClassNotFoundException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        } catch (InstantiationException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        } catch (IllegalAccessException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        } catch (UnsupportedLookAndFeelException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        
        
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    LoginDialog dialog = new LoginDialog();
                    dialog.addWindowListener(new WindowAdapter() {
                        public void windowClosing(WindowEvent e) {
                            System.exit(0);
                        }
                    });
                    dialog.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }
    
    public LoginDialog() {
        super();
        setResizable(false);
        setTitle("在线聊天登录框");
        getContentPane().setLayout(null);
        setBounds(100, 100, 427, 301);//注册时高度为578，不注册是301
        
        //设置窗口居中
        this.setLocation(Center.getPoint(this.getSize()));

        final JButton button_1 = new JButton();
        button_1.setText("登录");
        button_1.setBounds(230, 222, 106, 36);
        getContentPane().add(button_1);

        final JTextField textField_1 = new JTextField();
        textField_1.setBounds(148, 90, 192, 42);
        getContentPane().add(textField_1);

        final JLabel label = new JLabel();
        label.setText("帐    号");
        label.setBounds(76, 102, 66, 18);
        getContentPane().add(label);

        final JLabel label_1 = new JLabel();
        label_1.setText("密    码");
        label_1.setBounds(76, 167, 66, 18);
        getContentPane().add(label_1);

        final JPasswordField passwordField = new JPasswordField();
        passwordField.setBounds(148, 155, 192, 42);
        getContentPane().add(passwordField);

        final JButton button = new JButton();
        button.addActionListener(new ActionListener() {
            public void actionPerformed(final ActionEvent e) {
                if(LoginDialog.this.getHeight()==301) {
                    LoginDialog.this.setSize(427, 578);
                }else {
                    LoginDialog.this.setSize(427, 301);
                }
　　　　　　　　　　//设置窗口不断居中
                LoginDialog.this.setLocation(Center.getPoint(LoginDialog.this.getSize()));
            }
        });
        button.setText("注册");
        button.setBounds(76, 222, 106, 36);
        getContentPane().add(button);

        final JPanel panel = new JPanel();
        panel.setLayout(null);
        panel.setBorder(new TitledBorder(null, "注册用户", TitledBorder.DEFAULT_JUSTIFICATION, TitledBorder.DEFAULT_POSITION, null, null));
        panel.setBounds(10, 278, 401, 226);
        getContentPane().add(panel);

        final JLabel label_2 = new JLabel();
        label_2.setBounds(44, 41, 65, 18);
        label_2.setText("手机号：");
        panel.add(label_2);

        textField = new JTextField();
        textField.setBounds(115, 35, 225, 30);
        panel.add(textField);

        final JButton button_2 = new JButton();
        button_2.setText("发送验证");
        button_2.setBounds(243, 75, 97, 30);
        panel.add(button_2);

        textField_2 = new JTextField();
        textField_2.setBounds(115, 104, 95, 30);
        panel.add(textField_2);

        final JLabel label_3 = new JLabel();
        label_3.setText("验证码：");
        label_3.setBounds(44, 110, 65, 18);
        panel.add(label_3);

        passwordField_1 = new JPasswordField();
        passwordField_1.setBounds(115, 143, 231, 30);
        panel.add(passwordField_1);

        passwordField_2 = new JPasswordField();
        passwordField_2.setBounds(115, 175, 231, 30);
        panel.add(passwordField_2);

        final JLabel label_4 = new JLabel();
        label_4.setText("密        码：");
        label_4.setBounds(44, 149, 65, 18);
        panel.add(label_4);

        final JLabel label_5 = new JLabel();
        label_5.setText("验证密码：");
        label_5.setBounds(44, 181, 65, 18);
        panel.add(label_5);

        final JButton button_3 = new JButton();
        button_3.setBounds(47, 510, 97, 30);
        getContentPane().add(button_3);
        button_3.setText("放弃");

        final JButton button_4 = new JButton();
        button_4.setBounds(262, 510, 97, 30);
        getContentPane().add(button_4);
        button_4.setText("注册用户");
    }
    
}