Java的事件驱动入门（三）——完成一个简单的计算器。

迷南。 2023-08-17 15:34 124阅读 0赞

# 效果 #

![在这里插入图片描述][20190926184653158.gif]

# 代码 #

package Test;
    
    import javax.swing.*;
    import java.awt.*;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    
    public class calculator extends JFrame {
        
        private JButton jbtNumber0=new JButton("0");
        private JButton jbtNumber1=new JButton("1");
        private JButton jbtNumber2=new JButton("2");
        private JButton jbtNumber3=new JButton("3");
        private JButton jbtNumber4=new JButton("4");
        private JButton jbtNumber5=new JButton("5");
        private JButton jbtNumber6=new JButton("6");
        private JButton jbtNumber7=new JButton("7");
        private JButton jbtNumber8=new JButton("8");
        private JButton jbtNumber9=new JButton("9");
        private JButton jbtAdd=new JButton("+");
        private JButton jbtEqual=new JButton("=");
        private JButton jbtMinus=new JButton("-");
        private JButton jbtMultiply=new JButton("x");
        private JButton jbtDiv=new JButton("÷");
        private JButton jbtReset=new JButton("复位");
        private JLabel label1=new JLabel("请输入数据");
        private double add;
        private double added;
        private double total;
        private boolean flagAdd;
        private boolean flagMinus;
        private boolean flagMultiply;
        private boolean flagDiv;
        private boolean flagEqual;
        private JButton[] jbt={
        jbtNumber0,jbtNumber1,jbtNumber2,jbtNumber3,jbtNumber4,jbtNumber5,jbtNumber6,
        jbtNumber7,jbtNumber8,jbtNumber9};
        private JButton[] jbt2={
        jbtAdd,jbtMinus,jbtMultiply,jbtDiv};
        private String[] jbt3={
        "+","-","x","÷"};
        //private Boolean[] flag={flagAdd,flagMinus,flagMultiply,flagDiv,flagEqual};
    
    
    
        public calculator(){
        
                JPanel panel=new JPanel();
                ButtonListener listener=new ButtonListener();
                for (int i = 0; i < jbt.length; i++) {
        
                jbt[i].addActionListener(listener);
                jbtEqual.addActionListener(listener);
                jbtReset.addActionListener(listener);
                panel.add(jbt[i]);
            }
            for (int i = 0; i <jbt2.length ; i++) {
        
                jbt2[i].addActionListener(listener);
                panel.add(jbt2[i]);
            }
            panel.add(jbtEqual);
            panel.add(jbtReset);
            add(label1,BorderLayout.NORTH);
                add(jbtReset,BorderLayout.SOUTH);
            add(panel);
        }
        class ButtonListener implements ActionListener{
        
            @Override
            public void actionPerformed(ActionEvent e) {
        
    
                for (int i = 0; i <jbt.length; i++) {
        
                    if(e.getSource()==jbt[i]){
        
                        added=i;
                        if (!flagAdd&!flagMinus&!flagMultiply&!flagDiv){
        
                            System.out.println(i);
                            add=i;
                            label1.setText(""+add);
                        }
                        if(flagAdd){
        
                            label1.setText(add+"+"+added);
                        }
                        else if(flagMinus){
        
                            label1.setText(add+"-"+added);
                        }
                        else if(flagMultiply){
        
                            label1.setText(add+"x"+added);
                        }
                        else if(flagDiv){
        
                            label1.setText(add+"÷"+added);
                        }
                        break;
                    }
                }
    
                if(e.getSource()==jbtEqual){
        
                    System.out.println("233");
                    if(flagAdd){
        
                        total=add+added;
                    }
                    else if(flagMinus){
        
                        total=add-added;
                    }
                    else if(flagMultiply){
        
                        total=add*added;
                    }
                    else if(flagDiv){
        
                        total=add/added;
                    }
                    label1.setText(""+total);
                }
                 else if(e.getSource()==jbtReset){
        
                    add=0;
                    added=0;
                    flagAdd=false;
                    flagMinus=false;
                    flagMultiply=false;
                    flagDiv=false;
                    label1.setText("请输入数据:");
                }
                 else if(e.getSource()==jbtAdd){
        
                     flagAdd=true;
                     label1.setText(add+"+");
                }
                else if(e.getSource()==jbtMinus){
        
                    flagMinus=true;
                    label1.setText(add+"-");
                }
                else if(e.getSource()==jbtMultiply){
        
                    flagMultiply=true;
                    label1.setText(add+"x");
                }
                else if(e.getSource()==jbtDiv){
        
                    flagDiv=true;
                    label1.setText(add+"÷");
                }
    
            }
        }
    
    
        public static void main(String[] args) {
        
            calculator frame=new calculator();
            frame.setTitle("Calculator");
            frame.setSize(400,200);
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setLocationRelativeTo(null);
            frame.setVisible(true);
    
        }
    }

[20190926184653158.gif]: /images/20230810/d24b70d5757f4ddfa243ec51ff468bd6.png