import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.*;
public class zyy {
       JFrame a1;
       JButton a2;
       JPanel a3;
       JTextField a4;
       String[] xiaosi= {"7","8","9","/","4","5","6","*","1","2","3","-","0",".","=","+"};
       public zyy() {
           a1=new JFrame("计算机");
           a3=new JPanel(new GridLayout(4,4,0,0));
           a4=new JTextField();
           a1.add(BorderLayout.NORTH,a4);
           a1.add(BorderLayout.CENTER,a3);
           for(int i=0;i<16;i++) {               
           a2=new JButton(xiaosi[i]);
           a3.add(a2);
           }
           a1.setVisible(true);
           a1.setSize(400,200);       
       }
       public static void main(String[] args) {
           new zyy();
       }
}

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;
public class zy implements ActionListener {
    JFrame a1;
    JButton a2,a22,a222;
    JPanel a3,a4;
    BorderLayout a5;
public zy(){
    a1=new JFrame();
    a3=new JPanel();
    a4=new JPanel();
    new BorderLayout();
    a1.add(BorderLayout.NORTH,a3);
    a1.add(BorderLayout.CENTER,a4);
    a2=new JButton("红色");
    a2.addActionListener(this);
    a3.add(a2);
    a22=new JButton("绿色");
    a22.addActionListener(this);
    a3.add(a22);
    a222=new JButton("蓝色");
    a222.addActionListener(this);
    a3.add(a222);    
    a1.setVisible(true);
    a1.setSize(400,300);
}
public static void main(String[] args){
    new zy();
}
public void actionPerformed(ActionEvent e){
    JButton b=(JButton)e.getSource();
    if(b==a2) {
    a4.setBackground(Color.RED);
    }else if(b==a22) {
    a4.setBackground(Color.GREEN);
    }else if(b==a222) {
    a4.setBackground(Color.BLUE);
    }
}
}