Question

帮忙编写一个JAVA的程序

编写一个应用程序，有一个标题为“计算”的窗口，窗口的布局为flowlayout布局， 设计4个按钮，分别命名为，加，差，积，除…另外，窗口中还有3个文本框， 单击相应的按钮，将3个文本框的数字做运算，在第三个文本框中显示结果， 要求处理numberformatexception

393253310@qq.com

Answer 1

package swing;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;

public class TestResult extends JFrame implements ActionListener{
JTextField jfforward,jfcenter,jfbehind;
JButton jequals;
JComboBox list;
JLabel jl;
TestResult(){
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLayout(new FlowLayout());
jfforward = new JTextField(8);
jl = new JLabel();
jfcenter = new JTextField(8);
jfbehind = new JTextField(8);
jequals = new JButton("=");
list = new JComboBox();
setTitle("四则运算");
list.addItem("+");
list.addItem("-");
list.addItem("*");
list.addItem("/");
add(jfforward);
add(list);
add(jfcenter);
add(jequals);
add(jfbehind);
add(jl);
jequals.addActionListener(this);
this.setResizable(false);
this.setSize(500, 500);
this.setVisible(true);

}

public static void main(String[] args) {
new TestResult();
}

public void actionPerformed(ActionEvent e) {
if(e.getSource()==jequals){
switch(list.getSelectedIndex()){
case 0:try{
int n = Integer.parseInt(jfforward.getText());
int m = Integer.parseInt(jfcenter.getText());
int sum=n+m;
jfbehind.setText(""+sum);
}catch(Exception e3){
jl.setText("你输入了非法字符");
jfforward.setText("");
jfcenter.setText("");
}
break;
case 1:try{jl.setText("");
int n = Integer.parseInt(jfforward.getText());
int m = Integer.parseInt(jfcenter.getText());
int sum=n-m;
jfbehind.setText(""+sum);
}catch(Exception e2){
jl.setText("你输入了非法字符");
jfforward.setText("");
jfcenter.setText("");
}
break;
case 2:try{
jl.setText("");
int n = Integer.parseInt(jfforward.getText());
int m = Integer.parseInt(jfcenter.getText());
int sum=n*m;
jfbehind.setText(""+sum);
}catch(Exception e1){
jl.setText("你输入了非法字符");
jfforward.setText("");
jfcenter.setText("");
}
break;
case 3:
if(jfcenter.getText()!=null){
try{jl.setText("");
int n = Integer.parseInt(jfforward.getText());
int m = Integer.parseInt(jfcenter.getText());
int sum=n/m;
jfbehind.setText(""+sum);
}catch(Exception eo){
jl.setText("你输入了非法字符");
jfforward.setText("");
jfcenter.setText("");
}
}
break;
}

}
}

}

追问

能不能帮忙直接做出来，谢谢、、

追答

把Exception 改为 numberformatexception

追问

不好意思
我不会这个，这是帮朋友要的，能不能做个成品出来。。。谢谢了

追答

public void actionPerformed(ActionEvent e) {
if(e.getSource()==jequals){
switch(list.getSelectedIndex()){
case 0:try{
int n = Integer.parseInt(jfforward.getText());
int m = Integer.parseInt(jfcenter.getText());
int sum=n+m;
jfbehind.setText(""+sum);
}catch( NumberFormatException e3){
jl.setText("输入了非法字符");
jfforward.setText("");
jfcenter.setText("");
}
break;
case 1:try{jl.setText("");
int n = Integer.parseInt(jfforward.getText());
int m = Integer.parseInt(jfcenter.getText());
int sum=n-m;
jfbehind.setText(""+sum);
}catch( NumberFormatException e2){
jl.setText("输入了非法字符");
jfforward.setText("");
jfcenter.setText("");
}
break;
case 2:try{
jl.setText("");
int n = Integer.parseInt(jfforward.getText());
int m = Integer.parseInt(jfcenter.getText());
int sum=n*m;
jfbehind.setText(""+sum);
}catch( NumberFormatException e1){
jl.setText("你输入了非法字符");
jfforward.setText("");
jfcenter.setText("");
}
break;
case 3:
if(jfcenter.getText()!=null){
try{jl.setText("");
int n = Integer.parseInt(jfforward.getText());
int m = Integer.parseInt(jfcenter.getText());
int sum=n/m;
jfbehind.setText(""+sum);
}catch( NumberFormatException eo){
jl.setText("输入了非法字符");
jfforward.setText("");
jfcenter.setText("");
}
}
break;
}

Answer 2

编写一个applet在屏幕上画椭圆，椭圆的大小和位置由鼠标决定(在左上角按下鼠标，右下角放开鼠标，再由此决定的矩形中画椭圆)