计算器小项目

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;

public class count extends JFrame {
public static JTextField t1;
public static JTextField t2;
public static JTextField tout;
public static JLabel label;
public static JButton jia;
public static JButton jian;
public static JButton cheng;
public static JButton chu;
ActionListener a;

public static void main(String[] args) {
count c = new count("计算器");
}
public count(String s) {
super(s);
this.create();
this.setVisible(true);

}
public void create() {
this.setBounds(100, 100, 200, 200);
this.setLayout(new FlowLayout());
t1 = new JTextField(15);
t2 = new JTextField(15);
this.add(t1);
this.add(t2);
this.add(jia = new JButton("+"));
this.add(jian = new JButton("-"));
this.add(cheng = new JButton("*"));
this.add(chu = new JButton("/"));
this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
label = new JLabel("=");
this.add(label);
tout = new JTextField(13);
this.add(tout);
a = new act();
jia.addActionListener(a);
jian.addActionListener(a);
cheng.addActionListener(a);
chu.addActionListener(a);
}
}
class act implements ActionListener {

public void actionPerformed(ActionEvent e) {

if (count.t1.getText().equals("")||count.t2.getText().equals("")) {
System.out.println("1111");
JOptionPane.showMessageDialog(null, "您未输入字符或者字符格式不正确！");
return;
} else {
String s1=count.t1.getText();
String s2=count.t2.getText();
String s3="";
double a = Float.parseFloat(s1);
double b = Float.parseFloat(s2);
if (e.getSource() == count.jia) {
s3 = String.valueOf(a+b);
}
if(e.getSource()==count.jian){
s3 = String.valueOf(a-b);
}
if(e.getSource()==count.cheng){
s3 = String.valueOf(a*b);
}
if(e.getSource()==count.chu){
DecimalFormat df = new DecimalFormat("####0.00");
    s3=df.format(a/b);
}
count.tout.setText(s3);
s1=s2=s3="";
}
}

}