java java强制JTextField只能是大写
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/11571779/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
java force JTextField to be uppercase only
提问by Junba Tester
Is there a way to force all user input in a JTextFieldto be uppercase in Java?
有没有办法JTextField在 Java 中强制所有用户输入 a为大写？
回答by sunil
a complete working example may help you
一个完整的工作示例可能会对您有所帮助
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);
}
}
回答by MadProgrammer
You have two immediate choices. You can supply your own document, which is little bit of work, or supply your own DocumentFilter
你有两个直接的选择。你可以提供你自己的document，这是一点点工作，或者提供你自己的DocumentFilter
Or, you just google and see what you find, like http://www.java2s.com/Code/Java/Swing-JFC/DocumentFilterthatmapslowercaseletterstouppercase.htmthis for example ;)
或者，您只需 google 并查看您找到的内容，例如http://www.java2s.com/Code/Java/Swing-JFC/DocumentFilterthatmapslowercaseletterstouppercase.htm;)
回答by Chan
Below is an example of DocumentFilter.
下面是一个例子DocumentFilter。
AbstractDocument document = (AbstractDocument) textfield
.getDocument();
document.setDocumentFilter(new DocumentFilter() {
@Override
public void insertString(FilterBypass fb, int offset,
String string, AttributeSet attr)
throws BadLocationException {
super.insertString(fb, offset, string.toUpperCase(), attr);
}
@Override
public void replace(FilterBypass fb, int offset, int length,
String text, AttributeSet attrs)
throws BadLocationException {
super.insertString(fb, offset, text.toUpperCase(), attrs);
}
});
