caculator.java

java program very good

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public final class Caculator extends JFrame {
       /**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	JTextField tf1,tf2,tf3;
       JButton changeButton,plus,minus,multiply,divide,mod;
       double n1,n2,n3;
       boolean change=true;    
       
       Caculator(){
           super("简单计算器");
           changeButton=new JButton("换肤");
           changeButton.addActionListener(new ButtonListener());
           plus=new JButton("+");
           minus=new JButton("-");
           multiply=new JButton("*");
           divide=new JButton("/");
           mod=new JButton("mod");
           tf1=new JTextField(10);
           tf2=new JTextField(10);
           tf3=new JTextField(10);
           changeSkin();           
           this.setSize(450,270);
           this.setVisible(true);
           this.setResizable(false);
           addListener();
        }
        public void changeSkin(){
            if(change==true){
                setContentPane(skin());
                change=false;
            }
            else{
                setContentPane(skin2());
                change=true;
            }
        }       
        private JPanel skin(){
           JPanel contentpanel=(JPanel)getContentPane();
           contentpanel.removeAll();
           JPanel panel1=new JPanel();
           panel1.setLayout(new FlowLayout());          
           panel1.add(tf1);          
           JPanel panel2=new JPanel();
           panel2.setLayout(new GridLayout(5,1,0,5));
           panel2.add(plus);           
           panel2.add(minus);
           panel2.add(multiply);
           panel2.add(divide);
           panel2.add(mod);
           panel1.add(panel2);         
           panel1.add(tf2);
           JLabel label1=new JLabel("=");
           panel1.add(label1);
           panel1.add(tf3);
           contentpanel.setLayout(new FlowLayout(0));
           JPanel panel0=new JPanel();
           panel0.add(changeButton);
           contentpanel.add(panel0);
           contentpanel.add(panel1);
           return contentpanel;
        }
        private JPanel skin2(){
            JPanel contentpanel=(JPanel)getContentPane();
            contentpanel.removeAll();
            JLabel lb1=new JLabel("第一个数:");
            JPanel panel1=new JPanel();
            panel1.setLayout(new FlowLayout(FlowLayout.LEFT,15,0));
            panel1.add(lb1);
            panel1.add(tf1);
            JLabel lb2=new JLabel("运算:");
            JPanel panel2=new JPanel();
            panel2.setLayout(new FlowLayout(FlowLayout.LEFT,28,0));
            panel2.add(lb2);
            panel2.add(plus);
            panel2.add(minus);
            panel2.add(multiply);
            panel2.add(divide);
            panel2.add(mod);
            JLabel lb3=new JLabel("第二个数:");
            JPanel panel3=new JPanel();
            panel3.setLayout(new FlowLayout(FlowLayout.LEFT,15,0));
            panel3.add(lb3);
            panel3.add(tf2);
            JLabel lb4=new JLabel("结果:");
            JPanel panel4=new JPanel();
            panel4.setLayout(new FlowLayout(FlowLayout.LEFT,28,0));
            panel4.add(lb4);
            panel4.add(tf3);
            JPanel content=new JPanel();
            content.setLayout(new GridLayout(4,1,0,15));
            content.add(panel1);
            content.add(panel2);
            content.add(panel3);
            content.add(panel4);
            contentpanel.setLayout(new FlowLayout(0,5,15));
            contentpanel.add(changeButton);
            contentpanel.add(content);
            return contentpanel;
        }
        public void addListener() {
            class Listener implements ActionListener {
                public void actionPerformed(ActionEvent e) {
               try{
                    int flag=1;
                    JButton source=new JButton();
                    source=(JButton)e.getSource();
                    n1=Double.parseDouble(tf1.getText());
                    n2=Double.parseDouble(tf2.getText());
                    if(source==plus) n3=n1+n2;
                    else if(source==minus) n3=n1-n2;
                    else if(source==multiply) n3=n1*n2;
                    else if(source==divide){
                        if(n2==0){
                            tf3.setText("无意义");
                            flag=0;
                        }
                        else
                        n3=n1/n2;
                    }
                    else{
                        if(n2==0){
                            tf3.setText("无意义");
                            flag=0;                            
                        }
                        else{
                            int yu;
                            yu=((int)n1)%((int)n2);
                            tf3.setText(Integer.toString(yu));
                            flag=0;
                        }
                    }
                  if(flag==1) tf3.setText(Double.toString(n3));
                }catch(Exception ex){tf3.setText("可能未初始化或不是数字");}
               }
            }
            Listener listener=new Listener();
            plus.addActionListener(listener);
            minus.addActionListener(listener);
            multiply.addActionListener(listener);
            divide.addActionListener(listener);
            mod.addActionListener(listener);
        }
        class ButtonListener implements ActionListener {
             public void actionPerformed(ActionEvent e){
                  changeSkin();
             }
        }
        public static void main(String[] args){
                 new Caculator();               
        }
    }