JAVA第一个GUI程序---计算器

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class Calc extends MouseAdapter {
JFrame list;
// Container con;
JTextField show;
JButton[] jbNum = new JButton[10];
JPanel jpMain; // 主面板
JPanel jpRight; // 右子面板主要用于存放运算符和等号
JPanel jpLight; // 左子面板用于存放数字,符号, “.”
JButton dight; // 小数点
JButton sign; // 正负号
JButton add; // 加号
JButton sub; // 减号
JButton multiply; // 乘号
JButton divide; // 除号
JButton power; // 求幂
JButton cos; // cos
JButton sin; // sin
JButton ln; // ln
JButton ce; // 清除
JButton equal; // 等于
JButton mod; // 取余
JButton sqrt; // sqrt
double sum = 0; // 临时结果
boolean b = false; // 监控运算符是否被点击,错误是否出现，用于实现下一次点击按钮时清空
operator i = operator.un; // 记录等号符点击前某一运算符点击次数，用于实现连加或者连减等

int op; // 记录操作符

// 操作符一包括+-*/%^
enum operator {
add, sub, mul, div, mod, pow, sin, cos, sqrt, ln, un
}

void display() {
// 创建主窗口，添加一个Text框，
list = new JFrame("计算器");
list.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
list.setSize(360, 230);
list.setLocation(400, 300);
list.setBackground(Color.LIGHT_GRAY); // 设置窗口背景颜色
list.setResizable(false);

list.setLayout(new FlowLayout(FlowLayout.CENTER));
show = new JTextField(31);
show.setHorizontalAlignment(JTextField.RIGHT); // 文本框内文字右对齐
show.setEditable(false); // 文本框不可编辑
list.add(show);
// 创建面板并设置布局
jpMain = new JPanel();
jpRight = new JPanel();
jpLight = new JPanel();
jpMain.setLayout(new GridLayout(1, 2));
jpRight.setLayout(new GridLayout(4, 3, 3, 3));
jpLight.setLayout(new GridLayout(4, 3, 3, 3));
list.add(jpMain);
jpMain.add(jpLight);
jpMain.add(jpRight);
// 创建0~9按钮对象
for (int i = 9; i >= 0; i--) {
jbNum[i] = new JButton(String.valueOf(i));
jbNum[i].setForeground(Color.BLUE);
jpLight.add(jbNum[i]);
jbNum[i].addMouseListener(this);
}
add = new JButton("+");
sub = new JButton("-");
multiply = new JButton("*");
divide = new JButton("/");
power = new JButton("x^y");
sin = new JButton("sin");
cos = new JButton("cos");
ln = new JButton("ln");
ce = new JButton("CE");
equal = new JButton("=");
mod = new JButton("%");
sqrt = new JButton("sqrt");
jpRight.add(divide);
jpRight.add(sqrt);
jpRight.add(ln);
jpRight.add(multiply);
jpRight.add(sin);
jpRight.add(mod);
jpRight.add(sub);
jpRight.add(cos);
jpRight.add(ce);
jpRight.add(add);
jpRight.add(power);
jpRight.add(equal);

// 给所有按钮注册监听器
dight = new JButton(".");
sign = new JButton("±");
jpLight.add(sign);
jpLight.add(dight);
add.addMouseListener(this);
sub.addMouseListener(this);
multiply.addMouseListener(this);
divide.addMouseListener(this);
power.addMouseListener(this);
sin.addMouseListener(this);
cos.addMouseListener(this);
ln.addMouseListener(this);
ce.addMouseListener(this);
equal.addMouseListener(this);
mod.addMouseListener(this);
sqrt.addMouseListener(this);
dight.addMouseListener(this);
sign.addMouseListener(this);
list.setVisible(true);

}

public void mouseClicked(MouseEvent e) {
// 0~9的输入
if (e.getSource() == jbNum[0]) {
input(0, e);
}
if (e.getSource() == jbNum[1]) {
input(1, e);
}
if (e.getSource() == jbNum[2]) {
input(2, e);
}
if (e.getSource() == jbNum[3]) {
input(3, e);
}
if (e.getSource() == jbNum[4]) {
input(4, e);
}
if (e.getSource() == jbNum[5]) {
input(5, e);
}
if (e.getSource() == jbNum[6]) {
input(6, e);
}
if (e.getSource() == jbNum[7]) {
input(7, e);
}
if (e.getSource() == jbNum[8]) {
input(8, e);
}
if (e.getSource() == jbNum[9]) {
input(9, e);
}

// 小数点,正负号，CE,等号
if (e.getSource() == dight) {
if (show.getText().indexOf('.') == -1) {
show.setText(show.getText() + ".");
}

}
if (e.getSource() == sign) {
if (show.getText().indexOf("-") == -1) {
show.setText("-" + show.getText());
} else {
show.setText(show.getText().replace('-', '\0'));
}

}
if (e.getSource() == ce) {
show.setText("0");
sum = 0;
i = operator.un;
b = false;
}
outer: if (e.getSource() == equal) {
try {
if (i == operator.un) {
b = true;
} else {
if (i == operator.add) {
sum += Double.parseDouble(show.getText());

}
if (i == operator.sub) {
sum -= Double.parseDouble(show.getText());

}
if (i == operator.mul) {
sum *= Double.parseDouble(show.getText());

}
if (i == operator.div) {
if (Double.parseDouble(show.getText()) != 0) {
sum /= Double.parseDouble(show.getText());

} else {
show.setText("ERROR");
b = true;
sum = 0;
break outer; // 不执行trimIn()方法 屏幕显示错误
}
}
if (i == operator.mod) {
sum %= Double.parseDouble(show.getText());

}
if (i == operator.pow) {
sum = Math.pow(sum, Double.parseDouble(show.getText()));

}
trimIn(sum);
}
} catch (Exception ex) {
show.setText("ERROR");
b = true;
sum = 0;
}

sum = 0;
i = operator.un;
b = true;
}
// 加减乘除//幂指函数//取余
if (e.getSource() == add) {
cal(i);
i = operator.add;
b = true;

}
if (e.getSource() == sub) {
cal(i);
i = operator.sub;
b = true;

}
if (e.getSource() == multiply) {
cal(i);
i = operator.mul;
b = true;

}
if (e.getSource() == divide) {
cal(i);
i = operator.div;
b = true;

}
if (e.getSource() == mod) {
cal(i);
i = operator.mod;
b = true;

}
if (e.getSource() == power) {
cal(i);
i = operator.pow;
b = true;

}

// sqrt，sin,cos,ln
try {
if (show.getText() != "ERROR") {
if (e.getSource() == sqrt) {
sum = Math.sqrt(Double.parseDouble(show.getText()));
trimIn(sum);
b = true;
}
if (e.getSource() == sin) {
sum = Math.sin(Double.parseDouble(show.getText()));
trimIn(sum);
b = true;
}
if (e.getSource() == cos) {
sum = Math.cos(Double.parseDouble(show.getText()));
trimIn(sum);
b = true;
}
if (e.getSource() == ln) {
sum = Math.log(Double.parseDouble(show.getText()));
trimIn(sum);
b = true;
}
}
} catch (Exception ex) {
show.setText("ERROR");
b = true;
}
}

// 用以四则运算和求幂和取模的方法
public void cal(operator i) {
try {
if (show.getText() != "ERROR") {
if (i == operator.un) {
sum = Double.parseDouble(show.getText());
}
if (i == operator.add) {
sum += Double.parseDouble(show.getText());
trimIn(sum);
}
if (i == operator.sub) {
sum -= Double.parseDouble(show.getText());
trimIn(sum);
}
if (i == operator.mul) {
sum *= Double.parseDouble(show.getText());
trimIn(sum);
}
if (i == operator.div) {
if (Double.parseDouble(show.getText()) != 0) {
sum /= Double.parseDouble(show.getText());
trimIn(sum);
} else {
//出现0后，把一切数据重置
show.setText("ERROR");
sum = 0;
b = true;
i=operator.un;
}
}
//取余
if (i == operator.mod) {
sum %= Double.parseDouble(show.getText());
trimIn(sum);
}
//幂指函数
if (i == operator.pow) {
sum = Math.pow(sum, Double.parseDouble(show.getText()));
trimIn(sum);
}
}
} catch (Exception ex) {
show.setText("ERROR");
b = true;
}
}

// 点击数字输入
public void input(int i, MouseEvent e) {
if (b == true) {
show.setText(String.valueOf(i));
b = false;
} else {
//判断0和.来清除整数时后面的点
if (show.getText().indexOf('0') == 0 && e.getSource() != dight) {
show.setText(String.valueOf(i));
} else {
show.setText(show.getText() + String.valueOf(i));
}
}
}

// sum的显示，整数的去掉小数点和0
public void trimIn(double sum) {
// if (show.getText().indexOf('.') != -1 &&
// show.getText().endsWith("0")) {
// show.setText((String.valueOf(sum).substring(0, String.valueOf(sum)
// .indexOf('.'))));
// } else
if (String.valueOf(sum).indexOf('.') != -1
&& String.valueOf(sum).endsWith("0")) {
show.setText((String.valueOf(sum).substring(0, String.valueOf(sum)
.indexOf('.'))));

} else if (Double.isNaN(sum)) {
show.setText("ERROR");         //不 是数字时 屏幕显示错误，并把sum置于0 运算符置UN
b = true;
sum = 0;
i = operator.un;
} else if (Double.isInfinite(sum)) {
show.setText("ERROR");          //出现infinite(无限大)时显示错误SUM置0运算符置UN
b = true;
sum = 0;
i = operator.un;
} else {
show.setText(String.valueOf(sum));
}
}

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Calc c = new Calc();
c.display();
}

}