calculator.java

教材管理系统

package bookmanager;

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



public class Calculator extends JFrame implements ActionListener{
  private JPanel jPanel1,jPanel2;
  private JTextField resultField;
  private JButton s1,s2,s3,s4,s5,s6,s7,s8,s9,s0,b1,b2,b3,b4,f1,f2;
  private boolean end,add,sub,mul,div;
  private String str;
  private double num1,num2;

public Calculator (){
   super("计算器");
   setSize(300,240);
   Container con=getContentPane();
   con.setLayout(new BorderLayout());
   jPanel1=new JPanel();
   jPanel1.setLayout(new GridLayout(1,1));
   jPanel2=new JPanel();
   jPanel2.setLayout(new GridLayout(4,4));
   resultField=new JTextField("0");
   jPanel1.add(resultField);
   con.add(jPanel1,BorderLayout.NORTH);
   s1=new JButton("  1  ");  s1.addActionListener(this);
   s2=new JButton("  2  ");  s2.addActionListener(this);
   s3=new JButton("  3  ");  s3.addActionListener(this);
   s4=new JButton("  4  ");  s4.addActionListener(this);
   s5=new JButton("  5  ");  s5.addActionListener(this);
   s6=new JButton("  6  ");  s6.addActionListener(this);
   s7=new JButton("  7  ");  s7.addActionListener(this);
   s8=new JButton("  8  ");  s8.addActionListener(this);
   s9=new JButton("  9  ");  s9.addActionListener(this);
   s0=new JButton("  0  ");  s0.addActionListener(this);
   b1=new JButton("  +  ");  b1.addActionListener(this);
   b2=new JButton("  -  ");  b2.addActionListener(this);
   b3=new JButton("  *  ");  b3.addActionListener(this);
   b4=new JButton("  /  ");  b4.addActionListener(this);
   f1=new JButton("  .  ");  f1.addActionListener(this);
   f2=new JButton("  =  ");  f2.addActionListener(this);
   jPanel2.add(s1);
   jPanel2.add(s2);
   jPanel2.add(s3);
   jPanel2.add(b1);
   jPanel2.add(s4);
   jPanel2.add(s5);
   jPanel2.add(s6);
   jPanel2.add(b2);
   jPanel2.add(s7);
   jPanel2.add(s8);
   jPanel2.add(s9);
   jPanel2.add(b3);
   jPanel2.add(s0);
   jPanel2.add(f1);
   jPanel2.add(f2);
   jPanel2.add(b4);
   con.add(jPanel2,BorderLayout.CENTER);
    try {
      jbInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }



   }
public void num(int i){
  String s = null;
  s=String.valueOf(i);
  if(end){
   //如果数字输入结束，则将文本框置零，重新输入
    resultField.setText("0");
    end=false;

    }
  if((resultField.getText()).equals("0")){
   //如果文本框的内容为零，则覆盖文本框的内容
   resultField.setText(s);

   }
  else{
    //如果文本框的内容不为零，则在内容后面添加数字
    str = resultField.getText() + s;
    resultField.setText(str);

    }
 }

public void actionPerformed(ActionEvent e){ //数字事件
    if(e.getSource()==s1)
     num(1);
    else if(e.getSource()==s2)
    num(2);
    else if(e.getSource()==s3)
    num(3);
    else if(e.getSource()==s4)
    num(4);
    else if(e.getSource()==s5)
    num(5);
    else if(e.getSource()==s6)
    num(6);
    else if(e.getSource()==s7)
    num(7);
    else if(e.getSource()==s8)
    num(8);
    else if(e.getSource()==s9)
    num(9);
    else if(e.getSource()==s0)
    num(0);

    //符号事件
    else if(e.getSource()==b1)
    sign(1);
    else if(e.getSource()==b2)
    sign(2);
    else if(e.getSource()==b3)
    sign(3);
    else if(e.getSource()==b4)
    sign(4);
    //等号
    else if(e.getSource()==f1){
    str=resultField.getText();
    if(str.indexOf(".")<=1){
     str+=".";
     resultField.setText(str);
     }
    }
    else if(e.getSource()==f2){
    num2=Double.parseDouble(resultField.getText());



    if(add){
     num1=num1 + num2;}
    else if(sub){
     num1=num1 - num2;}
    else if(mul){
     num1=num1 * num2;}
    else if(div){
     num1=num1 / num2;}
  resultField.setText(String.valueOf(num1));
  end=true;
  }


  }
public void sign(int s){
   if(s==1){
    add=true;
    sub=false;
    mul=false;
    div=false;
    }
    else if(s==2){
     add=false;
     sub=true;
     mul=false;
     div=false;
     }
    else if(s==3){
     add=false;
     sub=false;
     mul=true;
     div=false;
      }
    else if(s==4){
     add=false;
     sub=false;
     mul=false;
     div=true;
     }
  num1=Double.parseDouble(resultField.getText());
  end=true;
 }
public static void main(String[] args){
     Calculator  th1=new  Calculator ();
    th1.show();
    }
  private void jbInit() throws Exception {
    this.getContentPane().setBackground(UIManager.getColor("InternalFrame.inactiveTitleForeground"));
  }
    }