public class Calculate extends JFrame { /**
* @param args
*/
JFrame f=new JFrame();
JTextField t1=new JTextField(4);
JComboBox c=new JComboBox();
JTextField t2=new JTextField(4);
JLabel l=new JLabel("=");
JTextField t4=new JTextField(4);
public void frame(){
f.setLayout(new GridLayout(6,1));
c.addItem("+");
c.addItem("-");
c.addItem("*");
c.addItem("/");
JButton b=new JButton("计算");
b.addActionListener(new js());
JPanel panel=new JPanel();
JPanel panel1=new JPanel();
JPanel panel2=new JPanel();
JPanel panel3=new JPanel();
JPanel p1=new JPanel();
JPanel p2=new JPanel();
f.add(p1);
f.add(panel);
f.add(panel1);
f.add(panel2);
f.add(panel3);
f.add(p2);
p1.add(t1);
p1.add(c);
p1.add(t2);
p1.add(l);
p1.add(t4);
p2.add(b);
f.setSize(300,300);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
Calculate a=new Calculate();
a.frame();
// TODO 自动生成方法存根 }
class js implements ActionListener{
public void actionPerformed(ActionEvent arg0) { String s1=t1.getText();
String s2=t2.getText();
int op=c.getSelectedIndex();
try{
Double a=Double.parseDouble(s1);
Double b=Double.parseDouble(s2);
Double c=null;
switch(op){
case 0: c=a+b; t4.setText(c.toString());break;
case 1: c=a-b; t4.setText(c.toString());break;
case 2: c=a*b; t4.setText(c.toString());break;
case 3: c=a/b; t4.setText(c.toString());break;
}
}catch(Exception e1){
e1.printStackTrace();
JOptionPane.showMessageDialog(null,"请输入数字");
}
}
}
}
最近刚学完GUI和事件,写了个简单计算器。但是我想改改,用按钮方式点那数字,那是不是说我要设置9个按钮,然后添加9个兼听器,然后再建九个
这样的类 class js implements ActionListener{
public void actionPerformed(ActionEvent arg0) {}
反正我想法是这样的,觉得很有时间,所以就想尝试下。但后来发觉当我用jButton new 一个新的按钮 b0, 设置第二个兼听器的时候,也nwe 了个类名ling()(个类似上面 js()),但发觉似乎不可用,大家有什么办法吗? 只是想实现通过鼠标点0-9 数字 计算加减乘除
* @param args
*/
JFrame f=new JFrame();
JTextField t1=new JTextField(4);
JComboBox c=new JComboBox();
JTextField t2=new JTextField(4);
JLabel l=new JLabel("=");
JTextField t4=new JTextField(4);
public void frame(){
f.setLayout(new GridLayout(6,1));
c.addItem("+");
c.addItem("-");
c.addItem("*");
c.addItem("/");
JButton b=new JButton("计算");
b.addActionListener(new js());
JPanel panel=new JPanel();
JPanel panel1=new JPanel();
JPanel panel2=new JPanel();
JPanel panel3=new JPanel();
JPanel p1=new JPanel();
JPanel p2=new JPanel();
f.add(p1);
f.add(panel);
f.add(panel1);
f.add(panel2);
f.add(panel3);
f.add(p2);
p1.add(t1);
p1.add(c);
p1.add(t2);
p1.add(l);
p1.add(t4);
p2.add(b);
f.setSize(300,300);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
Calculate a=new Calculate();
a.frame();
// TODO 自动生成方法存根 }
class js implements ActionListener{
public void actionPerformed(ActionEvent arg0) { String s1=t1.getText();
String s2=t2.getText();
int op=c.getSelectedIndex();
try{
Double a=Double.parseDouble(s1);
Double b=Double.parseDouble(s2);
Double c=null;
switch(op){
case 0: c=a+b; t4.setText(c.toString());break;
case 1: c=a-b; t4.setText(c.toString());break;
case 2: c=a*b; t4.setText(c.toString());break;
case 3: c=a/b; t4.setText(c.toString());break;
}
}catch(Exception e1){
e1.printStackTrace();
JOptionPane.showMessageDialog(null,"请输入数字");
}
}
}
}
最近刚学完GUI和事件,写了个简单计算器。但是我想改改,用按钮方式点那数字,那是不是说我要设置9个按钮,然后添加9个兼听器,然后再建九个
这样的类 class js implements ActionListener{
public void actionPerformed(ActionEvent arg0) {}
反正我想法是这样的,觉得很有时间,所以就想尝试下。但后来发觉当我用jButton new 一个新的按钮 b0, 设置第二个兼听器的时候,也nwe 了个类名ling()(个类似上面 js()),但发觉似乎不可用,大家有什么办法吗? 只是想实现通过鼠标点0-9 数字 计算加减乘除
public void actionPerformed(ActionEvent e)
有这个参数e传进来
你就可以判断点的是那个按钮
if(e.getSource() == xxx ) {
/do coding
}就是你每个按钮都要添加这个监听器
public void actionPerformed(ActionEvent arg0) {}
当然10个监听器也可以。。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*; public class Calculator extends JFrame { private Container container;
private GridBagLayout layout;
private GridBagConstraints constraints;
private JTextField displayField;//计算结果显示区
private String lastCommand;//保存+,-,*,/,=命令
private double result;//保存计算结果
private boolean start;//判断是否为数字的开始 public Calculator() { super("Calculator");
container=getContentPane();
layout=new GridBagLayout();
container.setLayout(layout);
constraints=new GridBagConstraints();
start=true;
result=0;
lastCommand = "=";
displayField=new JTextField(20);
displayField.setHorizontalAlignment(JTextField.RIGHT);
constraints.gridx=0;
constraints.gridy=0;
constraints.gridwidth=4;
constraints.gridheight=1;
constraints.fill=GridBagConstraints.BOTH;
constraints.weightx=100;
constraints.weighty=100;
layout.setConstraints(displayField,constraints);
container.add(displayField);
ActionListener insert = new InsertAction();
ActionListener command = new CommandAction();
addButton("Backspace",0,1,2,1,insert);
addButton("CE",2,1,1,1,insert);
addButton("C",3,1,1,1,insert);
addButton("7",0,2,1,1,insert);
addButton("8",1,2,1,1,insert);
addButton("9",2,2,1,1,insert);
addButton("/",3,2,1,1,command);
addButton("4",0,3,1,1,insert);
addButton("5",1,3,1,1,insert);
addButton("6",2,3,1,1,insert);
addButton("*",3,3,1,1,command);
addButton("1",0,4,1,1,insert);
addButton("2",1,4,1,1,insert);
addButton("3",2,4,1,1,insert);
addButton("-",3,4,1,1,command);
addButton("0",0,5,1,1,insert);
addButton("+/-",1,5,1,1,insert);//只显示"-"号,"+"没有实用价值
addButton(".",2,5,1,1,insert);
addButton("+",3,5,1,1,command);
addButton("=",0,6,4,1,command);
setSize(300,300);
setVisible(true); }
private void addButton(String label,int row,int column,int with,int height,ActionListener listener) { JButton button=new JButton(label);
constraints.gridx=row;
constraints.gridy=column;
constraints.gridwidth=with;
constraints.gridheight=height;
constraints.fill=GridBagConstraints.BOTH;
button.addActionListener(listener);
layout.setConstraints(button,constraints);
container.add(button);
}
private class InsertAction implements ActionListener { public void actionPerformed(ActionEvent event) { String input=event.getActionCommand();
if (start) {
displayField.setText("");
start=false;
if(input.equals("+/-"))
displayField.setText(displayField.getText()+"-");
} if(!input.equals("+/-")) {
if(input.equals("Backspace")) {
String str=displayField.getText();
if(str.length()>0)
displayField.setText(str.substring(0,str.length()-1));
}else if(input.equals("CE")||input.equals("C")) {
displayField.setText("0");
start=true;
}else
displayField.setText(displayField.getText()+input);
}
}
}
private class CommandAction implements ActionListener { public void actionPerformed(ActionEvent evt) {
String command=evt.getActionCommand();
if(start) {
lastCommand=command;
}else {
calculate(Double.parseDouble(displayField.getText()));
lastCommand=command;
start=true;
}
}
} public void calculate(double x) {
if (lastCommand.equals("+")) result+= x;
else if (lastCommand.equals("-")) result-=x;
else if (lastCommand.equals("*")) result*=x;
else if (lastCommand.equals("/")) result/=x;
else if (lastCommand.equals("=")) result=x;
displayField.setText(""+ result);
} public static void main(String []args) {
Calculator calculator=new Calculator();
calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
} }