Java实现简单的计算器

先来看看界面效果

源码如下：

package test1;

import java.awt.Frame;
import java.awt.TextField;
import java.awt.Button;
import java.awt.Panel;
import java.awt.GridLayout;

import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class calculate {
	TextField tfResult;
	Button btNum[],btOper[],btPoint,btEqual,btBack,btSqrt,btPingfang,btLifang;
	int num1,num2;//操作数
	char oper;//操作符
	boolean isNum;//代表数字标志位
	public void init(){
		Frame f;
		
		tfResult=new TextField();
		
		btNum=new Button[10];//数组对象
		for(int i=0;i<=9;i++){
			btNum[i]=new Button(i+"");
		}
		btOper=new Button[4];
		btOper[0]=new Button("+");
		btOper[1]=new Button("-");
		btOper[2]=new Button("*");
		btOper[3]=new Button("/");
		
		btPoint=new Button(".");
		btEqual=new Button("=");
		btBack=new Button("Backspace");
		btSqrt=new Button("Sqrt");
		btPingfang=new Button("2");
		btLifang=new Button("3");
		f=new Frame("小羊羔的计算器！");
		
		f.setSize(300,300);
		
		//放置组件
		f.add(tfResult,"North");
		Panel panel=new Panel();
		f.add(panel,"Center");
		GridLayout gl=new GridLayout(5,4);
		panel.setLayout(gl);
		panel.add(btNum[1]);
		panel.add(btNum[2]);
		panel.add(btNum[3]);
		panel.add(btOper[0]);
		
		panel.add(btNum[4]);
		panel.add(btNum[5]);
		panel.add(btNum[6]);
		panel.add(btOper[1]);
		
		panel.add(btNum[7]);
		panel.add(btNum[8]);
		panel.add(btNum[9]);
		panel.add(btOper[2]);
		
		panel.add(btNum[0]);
		panel.add(btPoint);
		panel.add(btEqual);
		panel.add(btOper[3]);
		
		panel.add(btBack);
		panel.add(btSqrt);
		panel.add(btPingfang);
		panel.add(btLifang);
		f.setVisible(true);
		
		//注册监听
		f.addWindowListener(new MyWinLis());
		//数字按钮注册监听
		MyNumLis mnl=new MyNumLis();
		for(int i=0;i<=9;i++)
			btNum[i].addActionListener(mnl);
		
		//操作符按钮注册监听
		MyOperLis mol=new MyOperLis();
		for(int j=0;j<=3;j++)
			btOper[j].addActionListener(mol);
		//等号按钮注册监听
		MyEqualLis mel=new MyEqualLis();
		btEqual.addActionListener(mel);
		//删除按钮注册监听
		MyBackLis mbl=new MyBackLis();
		btBack.addActionListener(mbl);
		//开根号按钮注册监听
		MySqrtLis msl=new MySqrtLis();
		btSqrt.addActionListener(msl);
		//平方按钮注册监听
		MyPingfangLis mpl=new MyPingfangLis();
		btPingfang.addActionListener(mpl);
		//百分号注册监听
		MyLifangLis mll=new MyLifangLis();
		btLifang.addActionListener(mll);
	}
	//定义监听器类
	class MyNumLis implements ActionListener{
		public void actionPerformed(ActionEvent e){
			String t=e.getActionCommand();
			String s=tfResult.getText();
			if(isNum==false)
				tfResult.setText(t);
			else 
				tfResult.setText(s+t);
			isNum=true;
		}
	}
	class MySqrtLis implements ActionListener{
		public void actionPerformed(ActionEvent e){
			double t=Double.parseDouble(tfResult.getText());
			tfResult.setText(Math.sqrt(t)+"");
			isNum=false;
		}
	}
	class MyPingfangLis implements ActionListener{
		public void actionPerformed(ActionEvent e){
			num1=Integer.parseInt(tfResult.getText());
			tfResult.setText(num1*num1+"");
		}
	}
	class MyLifangLis implements ActionListener{
		public void actionPerformed(ActionEvent e){
			num1=Integer.parseInt(tfResult.getText());
			tfResult.setText(num1*num1*num1+"");
		}
	}
	class MyOperLis implements ActionListener{
		public void actionPerformed(ActionEvent e){
			num1=Integer.parseInt(tfResult.getText());//转化为INT
			oper=e.getActionCommand().charAt(0);
			isNum=false;
		}
	}
	class MyEqualLis implements ActionListener{
		public void actionPerformed(ActionEvent e){
			int result=0;
			isNum=false;
			num2=Integer.parseInt(tfResult.getText());
			switch(oper){
				case '+':result=num1+num2;break;
				case '-':result=num1-num2;break;
				case '*':result=num1*num2;break;
				case '/':result=num1/num2;break;
			}
			tfResult.setText(result+"");
		}
	}
	class MyBackLis implements ActionListener{
		public void actionPerformed(ActionEvent e){
			tfResult.setText("");
			isNum=false;
		}
	}
	class MyWinLis extends WindowAdapter{
		public void windowClosing(WindowEvent e){
			e.getWindow().setVisible(false);
			e.getWindow().dispose();
			System.exit(0);
		}
	}
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		new calculate().init();
	}

}

11×5=？界面如下：