预想计算器图为：
简易计算器
如何实现？
1.画出计算器框架图
2.设置button的监听事件，在监听中实现将值传入到JTextField面板上，并在触发“+”等预算符时实现运算
贴上代码画框代码 用Java里的swing和awt
import javax.swing.*;
import java.awt.*;
public class CaculatorWindow extends JFrame {
private final String names[] = {"7","8","9","+","4","5","6","-","1","2","3","*","0",".","=","/"};
private JTextField textField;
CaculatorWindow() {
textField = new JTextField();
GridLayout gridLayout = new GridLayout(4, 4);
JPanel panel = new JPanel();//定义计算器下方面板
panel.setLayout(gridLayout);
JButton[] buttons = new JButton[names.length];
for (int count = 0; count < names.length; count++) {
buttons[count] = new JButton(names[count]);
panel.add(buttons[count]);
}
//设置文本框位于窗体NORTH位置
getContentPane().add(textField,BorderLayout.NORTH);
//将面板放置在窗体CENTER位置
getContentPane().add(panel,BorderLayout.CENTER);
this.setTitle("Caculator");
this.setBounds(80,80,300,200);
this.setResizable(false);
this.setVisible(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
new CaculatorWindow();
}
}
再贴上实现监听和运算过程代码
//数字按钮的响应事件
class NumButtonHandler implements ActionListener{
public void actionPerformed(ActionEvent event){
JButton object = (JButton)event.getSource();
char jButtonName = object.getText().charAt(0);
switch (jButtonName){
default:
setTextField(jButtonName);
break;
}
}
void setTextField(char jButttonName){
textField.setText(textField.getText()+String.valueOf(jButttonName));//使得之前textField上的字不会被覆盖
}
}
//加减乘除等于的响应事件
class opeButtonHandler implements ActionListener{
public void actionPerformed(ActionEvent event){
String command = event.getActionCommand();
if(command.equals("+")){
temp = Double.parseDouble(textField.getText()); //用于保存运算符号前一个数字
textField.setText("");
select = 1;
}
if(command.equals("-")){
temp = Double.parseDouble(textField.getText());
textField.setText("");
select = 2;
}
if(command.equals("*")){
temp = Double.parseDouble(textField.getText());
textField.setText("");
select = 3;
}
if(command.equals("/")){
temp = Double.parseDouble(textField.getText());
textField.setText("");
select = 4;
}
//在 = 处进行+-*/事件处理
if(command.equals("=")){
switch (select){
case 1:
number = Double.parseDouble(textField.getText());//用于保存运算符号后一个数字
textField.setText((temp+number)+"");
break;
case 2:
number = Double.parseDouble(textField.getText());
textField.setText((temp-number)+"");
break;
case 3:
number = Double.parseDouble(textField.getText());
textField.setText((temp*number)+"");
break;
case 4:
number = Double.parseDouble(textField.getText());
textField.setText((temp/number)+"");
break;
}
}
}
}
NumButtonHandler numButtonHandler = new NumButtonHandler();
for (int count = 0; count < names.length; count++) {
if(count == 3 || count == 7 || count == 11 || count == 14 || count == 15)
buttons[count].addActionListener(new opeButtonHandler());
else
buttons[count].addActionListener(numButtonHandler);
}
贴上完整代码
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class CaculatorWindow extends JFrame {
private final String names[] = {"7","8","9","+","4","5","6","-","1","2","3","*","0",".","=","/"};
private JTextField textField;
private int select = 0;
private double temp = 0.0;
private double number;
CaculatorWindow() {
textField = new JTextField();
GridLayout gridLayout = new GridLayout(4, 4);
JPanel panel = new JPanel();//定义计算器下方面板
panel.setLayout(gridLayout);
JButton[] buttons = new JButton[names.length];
for (int count = 0; count < names.length; count++) {
buttons[count] = new JButton(names[count]);
panel.add(buttons[count]);
}
//数字按钮的响应事件
class NumButtonHandler implements ActionListener{
public void actionPerformed(ActionEvent event){
JButton object = (JButton)event.getSource();
char jButtonName = object.getText().charAt(0);
switch (jButtonName){
default:
setTextField(jButtonName);
break;
}
}
void setTextField(char jButttonName){
textField.setText(textField.getText()+String.valueOf(jButttonName));//使得之前textField上的字不会被覆盖
}
}
//加减乘除等于的响应事件
class opeButtonHandler implements ActionListener{
public void actionPerformed(ActionEvent event){
String command = event.getActionCommand();
if(command.equals("+")){
temp = Double.parseDouble(textField.getText()); //用于保存运算符号前一个数字
textField.setText("");
select = 1;
}
if(command.equals("-")){
temp = Double.parseDouble(textField.getText());
textField.setText("");
select = 2;
}
if(command.equals("*")){
temp = Double.parseDouble(textField.getText());
textField.setText("");
select = 3;
}
if(command.equals("/")){
temp = Double.parseDouble(textField.getText());
textField.setText("");
select = 4;
}
//在 = 处进行+-*/事件处理
if(command.equals("=")){
switch (select){
case 1:
number = Double.parseDouble(textField.getText());//用于保存运算符号后一个数字
textField.setText((temp+number)+"");
break;
case 2:
number = Double.parseDouble(textField.getText());
textField.setText((temp-number)+"");
break;
case 3:
number = Double.parseDouble(textField.getText());
textField.setText((temp*number)+"");
break;
case 4:
number = Double.parseDouble(textField.getText());
textField.setText((temp/number)+"");
break;
}
}
}
}
NumButtonHandler numButtonHandler = new NumButtonHandler();
for (int count = 0; count < names.length; count++) {
if(count == 3 || count == 7 || count == 11 || count == 14 || count == 15)
buttons[count].addActionListener(new opeButtonHandler());
else
buttons[count].addActionListener(numButtonHandler);
}
//设置文本框位于窗体NORTH位置
getContentPane().add(textField,BorderLayout.NORTH);
//将面板放置在窗体CENTER位置
getContentPane().add(panel,BorderLayout.CENTER);
this.setTitle("Caculator");
this.setBounds(80,80,300,200);
this.setResizable(false);
this.setVisible(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
new CaculatorWindow();
}
}
现存问题
只能实现简单的加减乘除运算，并且在触发运算符时无法再JTextField上显示运算符，之前的数字也将消失
将要解决
即使触发运算符，也能保留之前输入数字
能实现运算符的优先等级，在计算器面板中加入更多运算符如%，(,)