java强制JTextField只能是大写 [英] java force JTextField to be uppercase only
本文介绍了java强制JTextField只能是大写的处理方法,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
是否有一种方法可以强制将 JTextField
中的所有用户输入在Java中变为大写?
Is there a way to force all user input in a JTextField
to be uppercase in Java?
推荐答案
一个完整的工作示例可能会对您有所帮助
a complete working example may help you
import java.awt.Dimension;
import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;
public class UpperCasedTextFieldTester extends JFrame {
/** */
private static final long serialVersionUID = -4767854098431909437L;
public UpperCasedTextFieldTester(){
setSize(200, 200);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new FlowLayout(FlowLayout.LEFT));
DocumentFilter filter = new UppercaseDocumentFilter();
JTextField firstName = new JTextField();
firstName.setPreferredSize(new Dimension(100, 20));
((AbstractDocument) firstName.getDocument()).setDocumentFilter(filter);
JTextField lastName = new JTextField();
lastName.setPreferredSize(new Dimension(100, 20));
((AbstractDocument) lastName.getDocument()).setDocumentFilter(filter);
add(firstName);
add(lastName);
}
public static void main(String[] args) {
new UpperCasedTextFieldTester().setVisible(true);
}
}
class UppercaseDocumentFilter extends DocumentFilter {
public void insertString(DocumentFilter.FilterBypass fb, int offset,
String text, AttributeSet attr) throws BadLocationException {
fb.insertString(offset, text.toUpperCase(), attr);
}
public void replace(DocumentFilter.FilterBypass fb, int offset, int length,
String text, AttributeSet attrs) throws BadLocationException {
fb.replace(offset, length, text.toUpperCase(), attrs);
}
}
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