事件监听 计算器界面

1.事件监听：

package 事件监听;
import java.awt.*;
import java.awt.event.*;
public  class Frame2 extends Frame implements ActionListener{
 private Button button1;
 public Frame2()
 {
  super("个人信息");
      this.setSize(250,220);//设计组件的尺寸
      this.setLocation(800,600);//设计组件显示的位置
      this.setBackground(Color.pink);//设计背景颜色
      this.setLayout(new FlowLayout());//设计容器为流布局，居中
      this.add(new Label("姓名"));
      this.add(new TextField("大大",20));
      this.add(new Label("性别"));
      this.add(new TextField("女",20));
      this.add(new Label("民族"));
      this.add(new TextField("汉",20));
      this.add(new Label("年龄"));
      this.add(new TextField("19",20));
      this.add(new Label("籍贯"));
      this.add(new TextField("青海",20));
      button1=new Button("OK");
      this.add(button1);
      button1.addActionListener(this);
      this.addWindowListener(new WinClose());
      this.setVisible(true);
 }
 public void actionPerformed(ActionEvent ev)
 {
  if(ev.getSource()==button1)
  {
   System.out.print("welcome");
  }
 }
 public static void main(String arg[])
 {
  new Frame2();
 }
     class WinClose implements WindowListener
 {
  public void windowClosing(WindowEvent ev)
  {
   System.exit(0);
  }
  public void windowOpened(WindowEvent ev) {}
  public void windowActivated(WindowEvent ev) {}
  public void windowDeactivated(WindowEvent ev) {}
  public void windowClose(WindowEvent ev) {}
  public void windowIconified(WindowEvent ev) {}
  public void windowDeiconified(WindowEvent ev) {}
  @Override
  public void windowClosed(WindowEvent arg0) {
   // TODO 自动生成的方法存根
   
  }
 }
 }

2.计算器：

package 计算器;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.Stack;   //Stack是一个后进先出的堆栈

public class Frame2 extends JFrame implements ActionListener {
    String []An= {"7","8","9","+","4","5","6","-",
            "1","2","3","*","0",".","=","/"};
    JButton b[]=new JButton[16];
    JTextField jt;
    String input="";      //输入的字符串
    public Frame2() {
        Container P=getContentPane();     //用getContentPane()方法获得JFrame的内容面板
        JPanel jp1=new JPanel();
        JPanel jp2=new JPanel();
        JPanel jp3=new JPanel();
        JButton b1=new JButton("清零");
        JButton b2=new JButton("退格");
        GridLayout g=new GridLayout(4,4,3,3);   //4*4网格,间距3
        jp1.setLayout(new BorderLayout());     //边布局
        jp2.setLayout(g);
        jp3.setLayout(new GridLayout(1, 2,3,3));

        jt=new JTextField();
        jt.setPreferredSize(new Dimension(160,30));   //文本大小
        jt.setHorizontalAlignment(SwingConstants.LEFT);  //左对齐
        P.add(jp1,BorderLayout.NORTH);  //北
        jp1.add(jt,BorderLayout.WEST);  //西
        jp1.add(jp3,BorderLayout.EAST);   //东
        jp3.add(b1);
        jp3.add(b2);
        b1.setBackground(Color.lightGray);
        b2.setBackground(Color.lightGray);
        b1.addActionListener(this);     //定义处理事件的方法
        b2.addActionListener(this);

        for(int i=0;i<16;i++)    //添加按钮
        {
            b[i]=new JButton(An[i]);
            jp2.add(b[i]);
            b[i].addActionListener(this);
        }
        P.add(jp2,BorderLayout.CENTER);
        setVisible(true);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setSize(300, 250);
        setTitle("计算器");
    }
    @Override
    public void actionPerformed(ActionEvent e) {
        int t=0;
        String s=e.getActionCommand();
        if(s.equals("+")||s.equals("-")||s.equals("*")||s.equals("/")) {
            input+=" "+s+" ";        //如果碰到运算符，就在运算符前后分别加一个空格
        }else if(s.equals("清零")) {
            input="";
        }else if(s.equals("退格")) {
            if((input.charAt(input.length()-1))==' ')     //检测字符串的最后一个字符是否为空格
            {
                input=input.substring(0,input.length()-3);     //如果是则删除末尾3个字符
            }
            else      //否则删除1个字符
                {
                input=input.substring(0,input.length()-1);
                }
        }
        else if(s.equals("=")) {
            input=compute(input);
            jt.setText(input);
            input="";
            t=1;
        }
        else
            input += s;
        if(t==0) {
            jt.setText(input);
        }
    }
    private String compute(String str) {
        String array[];
        array=str.split(" ");
        Stack<Double> s=new Stack<Double>();
        Double a=Double.parseDouble(array[0]);
        s.push(a);
        for(int i=1;i<array.length;i++) {
            if(i%2==1) {
                if(array[i].compareTo("+")==0)
                {
                    double b= Double.parseDouble(array[i+1]);
                    s.push(b);
                }
                if(array[i].compareTo("-")==0)
                {
                    double b= Double.parseDouble(array[i+1]);
                    s.push(-b);
                }
                if(array[i].compareTo("*")==0)
                {
                    double b= Double.parseDouble(array[i+1]);
                    double c=s.pop();
                    c*=b;
                    s.push(c);
                }
                if(array[i].compareTo("/")==0)
                {
                    double b= Double.parseDouble(array[i+1]);
                    double c=s.peek();
                    s.pop();
                    c/=b;
                    s.push(c);
                }
            }
        }
        double sum=0;
        while(!s.isEmpty()) {
            sum+=s.pop();
        }
        String result=String.valueOf(sum);
        return result;
    }
    public static void main(String[] args) {
        new Frame2();
    }
}