用Java怎么写一个计算器啊，监听器不会，按钮用循环在运行时不能显示，键盘有字符的输入、、、、、、求完整代码
首先：你的有一个静态界面，其实就是普通的java图形化界面开发。
其次：你可以给按钮添加监听。
然后：触发计算加减乘除的函数，得到返回结果。并将结果append在应该显示的组件中。
关于监听的设置方法：
public class Login extends JFrame implements ActionListener
//创建组件
jb1=new JButton("登录");
jb2=new JButton("重置");
//设置监听
jb1.addActionListener(this);
jb2.addActionListener(this);
@Override
public void actionPerformed(ActionEvent e) {
if(e.getActionCommand()=="登录")
{
//如果选中教师登录
if(jrb1.isSelected())
{
tealogin();
}else if(jrb2.isSelected()) //学生在登录系统
{
stulogin();
}
}else if(e.getActionCommand()=="重置")
{
clear();
}
}
import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.Frame;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingConstants;
import exampleFrame.Calculator2;
public class Calcutor4 extends JFrame implements ActionListener{
// 标志用户按的是否是整个表达式的第一个数字,或者是运算符后的第一个数字
private boolean firstDigit = true;
// 计算的中间结果。
private double resultNum = 0.0;
// 当前运算的运算符
private String operator = "=";
// 操作是否合法
private boolean operateValidFlag = true;
JPanel contentPane;
JPanel contentPane2;
JPanel contentPane3;
JTextField tex = new JTextField("0");
JButton a1 = new JButton("MC");
JButton a2 = new JButton("MR");
JButton a3 = new JButton("MS");
JButton a4 = new JButton("M+");
JButton a5 = new JButton("M-");
JButton b1 = new JButton("←");
JButton b2 = new JButton("CE");
JButton b3 = new JButton("C");
JButton b4 = new JButton("±");
JButton b5 = new JButton("√");
JButton c1 = new JButton("7");
JButton c2 = new JButton("8");
JButton c3 = new JButton("9");
JButton c4 = new JButton("/");
JButton c5 = new JButton("%");
JButton d1 = new JButton("4");
JButton d2 = new JButton("5");
JButton d3 = new JButton("6");
JButton d4 = new JButton("*");
JButton d5 = new JButton("½");
JButton e1 = new JButton("1");
JButton e2 = new JButton("2");
JButton e3 = new JButton("3");
JButton e4 = new JButton("-");
JButton f1 = new JButton("=");
JButton f2 = new JButton("0");
JButton f3 = new JButton(".");
JButton f4 = new JButton("+");
public Calcutor4() {
//主面板
contentPane = (JPanel)getContentPane();
contentPane.setLayout(null);
this.setResizable(false);
setSize(310, 399);
setTitle("计算器");
tex.setEnabled(false);
tex.setFont(new java.awt.Font("Dialog", Font.PLAIN, 20));
tex.setHorizontalAlignment(SwingConstants.RIGHT);
tex.setEditable(false);
tex.setBounds(new Rectangle(20, 10, 260, 30));
//设置jpane2
contentPane2 = (JPanel)new JPanel();
contentPane2.setLayout(new GridLayout(4,5,5,5));
contentPane2.setBounds(20,50,260, 200);
a1.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
a2.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
a3.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
a4.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
a5.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
b1.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
b2.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
b3.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
b4.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
b5.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
c1.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
c2.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
c3.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
c4.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
c5.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
d1.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
d2.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
d3.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
d4.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
d5.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
contentPane2.add(a1);
contentPane2.add(a2);
contentPane2.add(a3);
contentPane2.add(a4);
contentPane2.add(a5);
contentPane2.add(b1);
contentPane2.add(b2);
contentPane2.add(b3);
contentPane2.add(b4);
contentPane2.add(b5);
contentPane2.add(c1);
contentPane2.add(c2);
contentPane2.add(c3);
contentPane2.add(c4);
contentPane2.add(c5);
contentPane2.add(d1);
contentPane2.add(d2);
contentPane2.add(d3);
contentPane2.add(d4);
contentPane2.add(d5);
//设置面板3
contentPane3 = new JPanel();
contentPane3.setLayout(null);
contentPane3.setBounds(20,255,260, 200);
e1.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
e2.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
e3.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
e4.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
f1.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
f2.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
f3.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
f4.setFont(new java.awt.Font("宋体", Font.PLAIN, 12));
e1.setBounds(new Rectangle(0, 0, 48, 45));
e2.setBounds(new Rectangle(53,0, 48, 45));
e3.setBounds(new Rectangle(106, 0, 48, 45));
e4.setBounds(new Rectangle(159, 0, 48, 45));
f1.setBounds(new Rectangle(212, 0, 48, 100));
f2.setBounds(new Rectangle(0, 53, 101, 45));
f3.setBounds(new Rectangle(106, 53, 48, 45));
f4.setBounds(new Rectangle(159, 53, 48, 45));
contentPane3.add(e1);
contentPane3.add(e2);
contentPane3.add(e3);
contentPane3.add(e4);
contentPane3.add(f1);
contentPane3.add(f2);
contentPane3.add(f3);
contentPane3.add(f4);
//添加事件监听器
c1.addActionListener(this);
c2.addActionListener(this);
c3.addActionListener(this);
c4.addActionListener(this);
d1.addActionListener(this);
d2.addActionListener(this);
d3.addActionListener(this);
d4.addActionListener(this);
e1.addActionListener(this);
e2.addActionListener(this);
e3.addActionListener(this);
e4.addActionListener(this);
b1.addActionListener(this);
b3.addActionListener(this);
f1.addActionListener(this);
f2.addActionListener(this);
f3.addActionListener(this);
f4.addActionListener(this);
contentPane.add(contentPane3);
contentPane.add(contentPane2);
contentPane.add(tex);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public static void main(String[] args) {
Calcutor4 calculator3 = new Calcutor4();
}
@Override
public void actionPerformed(ActionEvent e) {
// 获取事件源的标签
String label = e.getActionCommand();
System.out.println(label);
if (label.equals("←")) {
// 用户按了"Backspace"键
handleBackspace();
} else if (label.equals("C")) {
// 用户按了"C"键
handleC();
} else if ("0123456789.".indexOf(label) >= 0) {
// 用户按了数字键或者小数点键
handleNumber(label);
} else {
// 用户按了运算符键
handleOperator(label);
}
}
private void handleBackspace() {
String text = tex.getText();
int i = text.length();
if (i > 0) {
// 退格，将文本最后一个字符去掉
text = text.substring(0, i - 1);
if (text.length() == 0) {
// 如果文本没有了内容，则初始化计算器的各种值
tex.setText("0");
firstDigit = true;
operator = "=";
} else {
// 显示新的文本
tex.setText(text);
}
}
}
/**
* 处理数字键被按下的事件
*
* @param key
*/
private void handleNumber(String key) {
if (firstDigit) {
// 输入的第一个数字
tex.setText(key);
} else if ((key.equals(".")) && (tex.getText().indexOf(".") < 0)) {
// 输入的是小数点，并且之前没有小数点，则将小数点附在结果文本框的后面
tex.setText(tex.getText() + ".");
} else if (!key.equals(".")) {
// 如果输入的不是小数点，则将数字附在结果文本框的后面
tex.setText(tex.getText() + key);
}
// 以后输入的肯定不是第一个数字了
firstDigit = false;
}
/**
* 处理C键被按下的事件
*/
private void handleC() {
// 初始化计算器的各种值
tex.setText("0");
firstDigit = true;
operator = "=";
}
/**
* 处理运算符键被按下的事件
*
* @param key
*/
private void handleOperator(String key) {
if (operator.equals("/")) {
// 除法运算
// 如果当前结果文本框中的值等于0
if (getNumberFromText() == 0.0) {
// 操作不合法
operateValidFlag = false;
tex.setText("除数不能为零");
} else {
resultNum /= getNumberFromText();
}
} else if (operator.equals("+")) {
// 加法运算
resultNum += getNumberFromText();
} else if (operator.equals("-")) {
// 减法运算
resultNum -= getNumberFromText();
} else if (operator.equals("*")) {
// 乘法运算
} else if (operator.equals("=")) {
// 赋值运算
resultNum = getNumberFromText();
}
if (operateValidFlag) {
// 双精度浮点数的运算
long t1;
double t2;
t1 = (long) resultNum;
t2 = resultNum - t1;
if (t2 == 0) {
tex.setText(String.valueOf(t1));
} else {
tex.setText(String.valueOf(resultNum));
}
}
// 运算符等于用户按的按钮
operator = key;
firstDigit = true;
operateValidFlag = true;
}
/**
* 从结果文本框中获取数字
*
* @return
*/
private double getNumberFromText() {
double result = 0;
try {
result = Double.valueOf(tex.getText()).doubleValue();
} catch (NumberFormatException e) {
}
return result;
}
}