Java?入門圖形用戶界面設(shè)計(jì)之事件處理下

更新時間：2022年02月16日 15:46:09 作者：小旺不正經(jīng)

圖形界面（簡稱GUI）是指采用圖形方式顯示的計(jì)算機(jī)操作用戶界面。與早期計(jì)算機(jī)使用的命令行界面相比，圖形界面對于用戶來說在視覺上更易于接受，本篇精講Java語言中關(guān)于圖形用戶界面的事件處理

Java程序設(shè)計(jì) 圖形用戶界面【八】事件處理下

動作事件及監(jiān)聽處理

想讓按鈕變得有意義，就必須使用事件處理

使用ActionListener接口處理按鈕的動作事件

方法	作用
void actionPerformed(ActionEvent e)	發(fā)生操作時調(diào)用

使用ActionListener監(jiān)聽

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

class ActionHandle{
    private JFrame frame = new JFrame("一");
    private JButton but = new JButton("顯示");
    private JLabel lab = new JLabel();
    private JTextField text = new JTextField(10);
    private JPanel pan = new JPanel();
    public ActionHandle(){
        Font font = new Font("Serief",Font.ITALIC+Font.BOLD,28);
        lab.setFont(font);
        lab.setText("請輸入信息");
        but.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if(e.getSource()==but){
                    lab.setText(text.getText());
                }
            }
        });
        frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
        frame.setLayout(new GridLayout(2,1));
        pan.setLayout(new GridLayout(1,2));
        pan.add(text);
        pan.add(but);
        frame.add(pan);
        frame.add(lab);
        frame.pack();
        frame.setVisible(true);
    }
}
public class Hello {
    public static void main(String[] args) {
        new ActionHandle();
    }
}

if(e.getSource()==but){} //判斷觸發(fā)源是否為按鈕

用戶登錄操作

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

class LoginCheck{
    private String username;
    private String password;
    public LoginCheck(String username,String password){
        this.username=username;
        this.password=password;
    }
    public boolean validate(){
        if("abc".equals(username)&&"123".equals(password)){
            return true;
        }else {
            return false;
        }
    }
}
class ActionHandle{
    private JFrame frame = new JFrame("一");
    private JButton sub = new JButton("登錄");
    private JButton res = new JButton("重置");
    private JLabel nameLab = new JLabel("用戶名：");
    private JLabel passLab = new JLabel("密  碼：");
    private JLabel infoLab = new JLabel("用戶登錄");
    private JTextField username = new JTextField();
    private JPasswordField password = new JPasswordField();
    public ActionHandle(){
        Font font = new Font("Serief",Font.BOLD,12);
        infoLab.setFont(font);
        sub.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if(e.getSource()==sub){
                    String uname = username.getText();
                    String upass = new String(password.getPassword());
                    LoginCheck log = new LoginCheck(uname,upass);
                    if(log.validate()){
                        infoLab.setText("登錄成功");
                    }else {
                        infoLab.setText("登錄失敗");
                    }
                }
                if(e.getSource()==res){
                    username.setText("");
                    password.setText("");
                    infoLab.setText("用戶登錄");
                }
            }
        });
        frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
        frame.setLayout(null);
        nameLab.setBounds(5,5,60,20);
        passLab.setBounds(5,30,60,20);
        infoLab.setBounds(5,65,220,30);
        username.setBounds(65,5,100,20);
        password.setBounds(65,30,100,20);
        sub.setBounds(165,5,60,20);
        res.setBounds(165,30,60,20);
        frame.add(nameLab);
        frame.add(passLab);
        frame.add(infoLab);
        frame.add(username);
        frame.add(password);
        frame.add(sub);
        frame.add(res);
        frame.setSize(280,130);
        frame.setVisible(true);
    }
}
public class Hello {
    public static void main(String[] args) {
        new ActionHandle();
    }
}

鍵盤事件及監(jiān)聽處理

KeyListener接口對鍵盤的操作進(jìn)行監(jiān)聽

方法	作用
void keyTyped(KeyEvent e)	鍵入某個鍵時調(diào)用
void keyPressed(KeyEvent e)	鍵盤按下時調(diào)用
void keyReleased(KeyEvent e)	鍵盤松開時調(diào)用

通過KeyEvent取得鍵盤鍵入的內(nèi)容

方法	作用
public char getKeyChar()	返回鍵入的字符，只針對于keyTyped有意義
public int getKeyCode()	返回輸入字符的鍵碼
public static String getKeyText(int keyCode)	返回此鍵的信息

實(shí)現(xiàn)鍵盤監(jiān)聽

import javax.swing.*;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

class MyKeyHandle extends JFrame implements KeyListener{
    private JTextArea text = new JTextArea();
    public MyKeyHandle(){
        super.setTitle("一");
        JScrollPane scr = new JScrollPane(text);
        scr.setBounds(5,5,300,200);
        super.add(scr);
        text.addKeyListener(this);
        super.setSize(310,210);
        super.setVisible(true);
        super.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
    }

    @Override
    public void keyTyped(KeyEvent e) {
        text.append("輸入的內(nèi)容是："+e.getKeyChar()+"\n");
    }

    @Override
    public void keyPressed(KeyEvent e) {
        text.append("鍵盤"+KeyEvent.getKeyText(e.getKeyCode())+"鍵按下\n");
    }

    @Override
    public void keyReleased(KeyEvent e) {
        text.append("鍵盤"+KeyEvent.getKeyText(e.getKeyCode())+"鍵松開\n");
    }
}
public class Hello {
    public static void main(String[] args) {
        new MyKeyHandle();
    }
}

使用KeyAdapter適配器

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

class MykeyHandle extends JFrame{
    private JTextArea text = new JTextArea();
    public MykeyHandle(){
        super.setTitle("一");
        JScrollPane scr = new JScrollPane(text);
        scr.setBounds(5,5,300,200);
        super.add(scr);
        text.addKeyListener(new KeyAdapter() {
            @Override
            public void keyTyped(KeyEvent e) {
                super.keyTyped(e);
                text.append("輸入的內(nèi)容是："+e.getKeyChar()+"\n");
            }
        });
        super.setSize(310,210);
        super.setVisible(true);
        super.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
    }
}
public class Hello {
    public static void main(String[] args) {
        new MykeyHandle();
    }
}

鼠標(biāo)事件及監(jiān)聽處理

MouseListener接口

方法	作用
void mouseClicked(MouseEvent e)	鼠標(biāo)單擊時調(diào)用（按下并釋放）
void mousePressed(MouseEvent e)	鼠標(biāo)按下時調(diào)用
void mouseReleased(MouseEvent e)	鼠標(biāo)松開時調(diào)用
void mouseEntered(MouseEvent e)	鼠標(biāo)進(jìn)入到組件時調(diào)用

MouseEvent類

方法	作用
public static final int BUTTON1	表示鼠標(biāo)左鍵的常量
public static final int BUTTON2	表示鼠標(biāo)滾軸的常量
public static final int BUTTON3	表示鼠標(biāo)右鍵的常量
public int getButton()	以數(shù)字形式返回按下的鼠標(biāo)鍵
public int getClickCount()	返回鼠標(biāo)的單擊次數(shù)
public static String getMouseModifiersText(int modifiers)	以字符串形式返回鼠標(biāo)按下的鍵信息
public int getX()	返回鼠標(biāo)操作的X坐標(biāo)
public int getY()	返回鼠標(biāo)操作的Y坐標(biāo)

import javax.swing.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

class MyMouseHandle extends JFrame implements MouseListener{
    private JTextArea text = new JTextArea();
    public MyMouseHandle(){
        super.setTitle("一");
        JScrollPane src = new JScrollPane(text);
        src.setBounds(5,5,300,200);
        super.add(src);
        text.addMouseListener(this);
        super.setSize(310,210);
        super.setVisible(true);
        super.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
    }
    public void mouseClicked(MouseEvent e){
        int c = e.getButton();
        String mouseInfo = null;
        if(c==MouseEvent.BUTTON1){
            mouseInfo="左鍵";
        }else if(c==MouseEvent.BUTTON3){
            mouseInfo="右鍵";
        }else {
            mouseInfo="滾軸";
        }
        text.append("鼠標(biāo)單擊"+mouseInfo+"\n");
    }

    @Override
    public void mousePressed(MouseEvent e) {
        text.append("鼠標(biāo)按下\n");
    }

    @Override
    public void mouseReleased(MouseEvent e) {
        text.append("鼠標(biāo)松開\n");
    }

    @Override
    public void mouseEntered(MouseEvent e) {
        text.append("鼠標(biāo)進(jìn)入組件\n");
    }

    @Override
    public void mouseExited(MouseEvent e) {
        text.append("鼠標(biāo)離開組件\n");
    }
}
public class Hello {
    public static void main(String[] args) {
        new MyMouseHandle();
    }
}

通過MouseAdapter實(shí)現(xiàn)對指定鼠標(biāo)操作的監(jiān)聽

import javax.swing.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

class MyMouseHandle extends JFrame{
    private JTextArea text = new JTextArea();
    public MyMouseHandle(){
        super.setTitle("一");
        JScrollPane scr = new JScrollPane(text);
        scr.setBounds(5,5,300,200);
        super.add(scr);
        text.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {
                super.mouseClicked(e);
                int c = e.getButton();
                String mouseInfo = null;
                if(c==MouseEvent.BUTTON1){
                    mouseInfo="左鍵";
                }else if (c==MouseEvent.BUTTON3){
                    mouseInfo="右鍵";
                }else {
                    mouseInfo="滾軸";
                }
                text.append("鼠標(biāo)單擊"+mouseInfo+"\n");
            }
        });
        super.setSize(310,210);
        super.setVisible(true);
        super.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
    }
}
public class Hello {
    public static void main(String[] args) {
        new MyMouseHandle();
    }
}

鼠標(biāo)拖拽事件及監(jiān)聽處理

MouseMotionListener接口

方法	作用
void mouseDragged(MouseEvent e)	在組件上按下并拖動時調(diào)用
void mouseMoved(MouseEvent e)	鼠標(biāo)移動到組件時調(diào)用

import javax.swing.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

class MyMouseMotionHandle extends JFrame{
    public MyMouseMotionHandle(){
        super.setTitle("一");
        super.addMouseMotionListener(new MouseMotionListener() {
            @Override
            public void mouseDragged(MouseEvent e) {
                System.out.println("鼠標(biāo)拖拽到：X="+e.getX()+
                        " Y="+e.getY());
            }

            @Override
            public void mouseMoved(MouseEvent e) {
                System.out.println("鼠標(biāo)移動到窗體");
            }
        });
        super.setSize(310,210);
        super.setVisible(true);
        super.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
    }
}
public class Hello {
    public static void main(String[] args) {
        new MyMouseMotionHandle();
    }
}

使用MouseMotionAdapter類

super.addMouseMotionListener(new MouseMotionAdapter() {
    @Override
    public void mouseDragged(MouseEvent e) {
        System.out.println("鼠標(biāo)拖拽到：X="+e.getX()+
                " Y="+e.getY());
    }
});

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