输入文本只接受数字

本文介绍了输入文本只接受数字的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我设计了一个带有一些JTextFields的小摆动GUI，但是它有一个validateVariables方法，它必须验证接口内的所有字段，有一个JTextField调用（IP）必须只接受int变量我该如何设置它这样吗？

I desinged a little swing GUI that has some JTextFields, but it has a validateVariables method that has to validate all the fields that are inside the interface, there's one JTextField called (IP) must accept only int Variables how can i set it up like that?

PS JTextfield是用nette工具创建的。

P.S the JTextfield was created it in netbeans with the palete tool.

推荐答案

这是JTextField的javadoc docs.oracle/javase/7/docs/api/javax/swing/JTextField.html

This is the javadoc of JTextField docs.oracle/javase/7/docs/api/javax/swing/JTextField.html

有示例

public class UpperCaseField extends JTextField { public UpperCaseField(int cols) { super(cols); } protected Document createDefaultModel() { return new UpperCaseDocument(); } static class UpperCaseDocument extends PlainDocument { public void insertString(int offs, String str, AttributeSet a) throws BadLocationException { if (str == null) { return; } char[] upper = str.toCharArray(); for (int i = 0; i < upper.length; i++) { upper[i] = Character.toUpperCase(upper[i]); } super.insertString(offs, new String(upper), a); } } }

此示例更改所有用户输入大写。 只需修改insertString方法，删除所有非数字字符，即可使文本字段仅接受数字。

This example changes all user input to upper case. Just modify the insertString method, remove all non-digit characters, you can make your text field accept digits only.

示例：

public void insertString(int offs, String str, AttributeSet a) throws BadLocationException { if (str == null) { return; } super.insertString(offs, str.replaceAll("[^0-9]", ""), a); }

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正如@MadProgrammer所说，DocumentFilter是另一种方法，例如：

As @MadProgrammer said, DocumentFilter is another way to do so, for example:

Document document = someJTextField.getDocument(); if (document instanceof AbstractDocument) { ((AbstractDocument) doc).setDocumentFilter(new DocumentFilter() { public void insertString(DocumentFilter.FilterBypass fb, int offset, String str, AttributeSet a) throws BadLocationException { fb.insertString(offset, str.replaceAll("[^0-9]", ""), a); } }); }