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();
        }
    
}