如何让jTextField只能输入数字啊?

zcsnet 2005-03-23 10:26:33

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xiaochuaner 2005-04-03

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很简单啊，
先得到一个string，然后依次遍历他的每个元素，如果用户输入的有字母或者其他，那么就返回pop提示窗口》》》》》》》
for(int i=0;i<string.length();i++)
string.charAt(i)=="a,b,c...."等等，则pop

Terminator_2004 2005-04-01

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我这里有段程序供你参考,不管对与不对!! 楼主给加点劳动分,

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

public class DivideByZeroTest extends JFrame implements ActionListener
{
private JTextField inputField1,inputField2,outputField;
private int number1,number2,result;

public DivideByZeroTest()
{
super("Demonstrating Exceptions");

Container container=getContentPane();
container.setLayout(new GridLayout(3,2));

container.add(new JLabel("Enter numerator",SwingConstants.RIGHT));
inputField1=new JTextField();
container.add(inputField1);

container.add(new JLabel("Enter denominator and press Enter",SwingConstants.RIGHT));
inputField2=new JTextField();
container.add(inputField2);
inputField2.addActionListener(this);

container.add(new JLabel("Result",SwingConstants.RIGHT));
outputField=new JTextField();
container.add(outputField);

this.setSize(425,100);
this.setVisible(true);

}
public void actionPerformed(ActionEvent event)
{
outputField.setText("");
try{
number1=Integer.parseInt(inputField1.getText());
number2=Integer.parseInt(inputField2.getText());

result=quotient(number1,number2);
outputField.setText(String.valueOf(result));
}
//用于捕捉从字符串到数字的非法转换
catch(NumberFormatException n){
JOptionPane.showMessageDialog(this,
"You must enter two Integers","Invalid number Format",
JOptionPane.ERROR_MESSAGE);
}
catch(ArithmeticException e){
JOptionPane.showMessageDialog(this,
e.toString()+"\n请输入大于0的数!","Arithmetic Exception",
JOptionPane.ERROR_MESSAGE);
}
}
public int quotient(int numberator,int denominator)
throws ArithmeticException
{
return numberator/denominator;
}
public static void main(String args[])
{
DivideByZeroTest d=new DivideByZeroTest();
d.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}

thrive_li 2005-03-31

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JFormattedTextField extends JTextField adding support for formatting arbitrary values, as well as retrieving a particular object once the user has edited the text. The following illustrates configuring a JFormattedTextField to edit dates:

JFormattedTextField ftf = new JFormattedTextField();
ftf.setValue(new Date());
Once a JFormattedTextField has been created, you can listen for editing changes by way of adding a PropertyChangeListener and listening for PropertyChangeEvents with the property name value.

myhotsun 2005-03-31

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编写自己的Document也不是一件容易的事啊！

powpow 2005-03-29

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extends JTextDocument类

重载 insertString函数，如果是非数字就return就行啦

再TextField.setDocument(new 你的新Document类)

无欲则钢 2005-03-26

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输入数据好象有事件源，你可以用这个

cyicecream 2005-03-25

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在舰艇里做判断，每输入一个字符就判断一次，利用ASCII

zhaohao19853 2005-03-25

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我以前也是在键盘事件里判断,但是在Document这个类了
有关于这方面的

yema55 2005-03-25

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JFormattedTextField tft1 = new JFormattedTextField(NumberFormat.getIntegerInstance());
tft1.setValue(new Integer(123));

chenweionline 2005-03-24

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textfield.setDocument(new IntegerDocument());

class IntegerDocument extends PlainDocument {
public void insertString(int offset, String s,
AttributeSet attributeSet) throws BadLocationException {
try {
Integer.parseInt(s);
}
catch(Exception ex) {
Toolkit.getDefaultToolkit().beep();
return;
}
super.insertString(offset, s, attributeSet);
}
}