输入文本只接受数字 [英] Input text only accepts numbers
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
http://docs.oracle.com/javase/7/docs/api/javax/swing/JTextField.html
This is the javadoc of JTextField http://docs.oracle.com/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);
}
----编辑----
---- EDIT ----
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);
}
});
}
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