java窗体程序复习一

系统管理员 2022-05-24 11:39 201阅读 0赞

案例显示了对控件的监听事件的不同使用方法。  
方法一：

package Component;
    
    import javax.swing.*;
    import java.awt.*;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    
    public class Buju5 extends JFrame implements ActionListener { 
    
    
        JButton btn1=new JButton("north");
        JButton btn2=new JButton("south");
        JButton btn3=new JButton("east");
        JButton btn4=new JButton("west");
        JLabel j1=new JLabel("进行按钮操作");
        Buju5(){
            setLayout(new BorderLayout());
    
            add(btn1,BorderLayout.NORTH);
            add(btn2,BorderLayout.SOUTH);
            add(btn3,BorderLayout.EAST);
            add(btn4,BorderLayout.WEST);
            add(j1,BorderLayout.CENTER);
            setVisible(true);
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            btn1.addActionListener(this);
            btn2.addActionListener(this);
            btn3.addActionListener(this);
            btn4.addActionListener(this);
    
        }
    
        @Override
        public void actionPerformed(ActionEvent e) {
            if(e.getSource()==btn1){
                j1.setText("north");
                btn1.setVisible(false);
                btn2.setVisible(true);
                btn3.setVisible(true);
                btn4.setVisible(true);
            }else if(e.getSource()==btn2){
                j1.setText("south");
                btn2.setVisible(false);
                btn1.setVisible(true);
                btn3.setVisible(true);
                btn4.setVisible(true);
            }
            else if(e.getSource()==btn3){
                j1.setText("east");
                btn2.setVisible(true);
                btn1.setVisible(true);
                btn3.setVisible(false);
                btn4.setVisible(true);
            }else if(e.getSource()==btn4){
                j1.setText("west");
                btn2.setVisible(true);
                btn1.setVisible(true);
                btn3.setVisible(true);
                btn4.setVisible(false);
            }
        }
    
        public static void main(String[] args) {
            Buju5 buju5=new Buju5();
            buju5.setBounds(300,250,300,200);
        }
    }

![这里写图片描述][70]

方法二：

package Component;
    
    import javax.swing.*;
    import java.awt.*;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    
    public class ya extends JFrame implements ActionListener { 
    
        JButton[] b=new JButton[4];
        JTextField textField=new JTextField(8);
        ya(){
            b[0]=new JButton("north");
            b[1]=new JButton("south");
            b[2]=new JButton("east");
            b[3]=new JButton("west");
            setLayout(new BorderLayout());
            add(b[0], BorderLayout.NORTH);
            add(b[1],BorderLayout.SOUTH);
            add(b[2],BorderLayout.EAST);
            add(b[3],BorderLayout.WEST);
    
            add(textField,BorderLayout.CENTER);
            for(int i=0;i<4;i++){
                b[i].addActionListener(this);
            }
    
            setVisible(true);
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            setBounds(100,100,300,300);
        }
    
    
        @Override
        public void actionPerformed(ActionEvent e) {
            for(int i=0;i<4;i++){
                String str=textField.getText();
                if(b[i]==e.getSource()){
                    textField.setText("btn "+str+" i\n");
                    b[i].setVisible(false);
                }else{
                    b[i].setVisible(true);
                }
            }
        }
    
        public static void main(String[] args) {
            ya ya=new ya();
        }
    }

![这里写图片描述][70 1]  
方法三：

package Component;
    
    import javax.swing.*;
    import java.awt.*;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    
    public class ma extends JFrame implements ActionListener { 
    
        JButton btn1=new JButton("north");
        JButton btn2=new JButton("south");
        JButton btn3=new JButton("east");
        JButton btn4=new JButton("west");
        JLabel j1=new JLabel("进行按钮操作");
        ma(){
            setLayout(new BorderLayout());
    
            add(btn1,BorderLayout.NORTH);
            add(btn2,BorderLayout.SOUTH);
            add(btn3,BorderLayout.EAST);
            add(btn4,BorderLayout.WEST);
            add(j1,BorderLayout.CENTER);
            setVisible(true);
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            btn1.addActionListener(this);
            btn2.addActionListener(this);
            btn3.addActionListener(this);
            btn4.addActionListener(this);
    
        }
        @Override
        public void actionPerformed(ActionEvent e) {
            int n=0;
            if(e.getSource()==btn1){
                n=1;
            }else if(e.getSource()==btn2){
                n=2;
            }else if(e.getSource()==btn3){
                n=3;
            }else if(e.getSource()==btn4){
                n=4;
            }
    
            switch (n){
                case 1:
                    j1.setText("north");
                    btn1.setVisible(false);
                    btn2.setVisible(true);
                    btn3.setVisible(true);
                    btn4.setVisible(true);
                    break;
                case 2:
                    j1.setText("south");
                    btn2.setVisible(false);
                    btn1.setVisible(true);
                    btn3.setVisible(true);
                    btn4.setVisible(true);
                    break;
                case 3:
                    j1.setText("east");
                    btn2.setVisible(true);
                    btn1.setVisible(true);
                    btn3.setVisible(false);
                    btn4.setVisible(true);
                    break;
                case 4:
                    j1.setText("west");
                    btn2.setVisible(true);
                    btn1.setVisible(true);
                    btn3.setVisible(true);
                    btn4.setVisible(false);
                    break;
            }
        }
    
        public static void main(String[] args) {
            ma ma=new ma();
            ma.setBounds(100,100,300,300);
        }
    }

![这里写图片描述][70 2]

[70]: /images/20220524/83b99e9257b14b4dbabd343cf50f02f8.png
[70 1]: /images/20220524/b107d684ef4c4287922029064277c830.png
[70 2]: /images/20220524/83b4a8252ec64bdeb4440c8b1a4bca5d.png