實驗十一：圖形界面二

實驗程序如下：
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Example1 extends JFrame {
?private int add=1,sub=2,mul=3,div=4;
?private int op=0;
?boolean ifOp;
?private String output="0";
?private Button[] jba=new Button[]{
?new Button("7"),new Button("8"),new Button("9"),new Button("+"),
?new Button("4"),new Button("5"),new Button("6"),new Button("-"),
?new Button("1"),new Button("2"),new Button("3"),new Button("*"),
?new Button("0"),new Button("."),new Button("="),new Button("/")};
?private JPanel jpt=new JPanel();
?private JPanel jpb=new JPanel();
?private JTextField jtf=new JTextField("");
?private Example1(){
? jpt.setLayout(new BorderLayout());
? jpt.add(jtf);
? this.add(jpt,BorderLayout.NORTH);
? jpb.setLayout(new GridLayout(4,4));
? for(int i=0;i<jba.length;i++){
? jpb.add(jba[i]);
? if(i==3||i==7||i==11||i==15||i==14)
? jba[i].addActionListener(new setOperate_Act());
? else
? jba[i].addActionListener(new setLabel_Act());
? }
? this.add(jpb,BorderLayout.CENTER);
? this.setSize(200, 200);?
? this.setResizable(false);
? this.setVisible(true);
? this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
?}
?private void operate(String x){double x1=Double.valueOf(x);
?double y=Double.valueOf(output);
?switch(op){
?case 0:output=x;break;
?case 1:output=String.valueOf(y+x1);break;
?case 2:output =String.valueOf(y-x1);break;
?case 3:output =String.valueOf(y*x1);break;
?case 4:
?if(x1!=0) output=String.valueOf(y/x1);
?else output="不能為0";
?break;
?}
?}
?public String add(String x){
?operate(x);
?op=add;
?return output;
?}
?public String subtract(String x){
? operate(x);
? op=sub;
?return output;
?}
?public String multiply(String x){
? operate(x);
? op=mul;
?return output;
?}
?public String divide(String x){
? operate(x);
? op=div;
?return output;
?}
?public String Equals(String x){
? operate(x);
? op=0;
?return output;
?}
?public void opClean(){
? op=0;
? output="0";
?}
?class setOperate_Act implements ActionListener{
? public void actionPerformed(ActionEvent e) {
? if(e.getSource()==jba[3]){
? jtf.setText(add(jtf.getText()));
? ifOp=true;
? }
? else if(e.getSource()==jba[7]){
? jtf.setText(subtract(jtf.getText()));
? ifOp=true;
? }
? else if(e.getSource()==jba[11]){
? jtf.setText(multiply(jtf.getText()));
? ifOp=true;
? }
? else if(e.getSource()==jba[15]){
? jtf.setText(divide(jtf.getText()));
? ifOp=true;
? }
? else if(e.getSource()==jba[14]){
? jtf.setText(Equals(jtf.getText()));
? ifOp=true;
? }
? }
? }
? class setLabel_Act implements ActionListener{
? public void actionPerformed(ActionEvent e) {
? Button tempb=(Button)e.getSource();
? if(ifOp){
? jtf.setText(tempb.getLabel());
? ifOp=false;
? }else {
? jtf.setText(jtf.getText()+tempb.getLabel());
? }
? }
? }
?
?public static void main(String[] args) {
? new Example1();
?}
}