java我想得到大写字母表，而不必按大写锁定键和shift键

Question

如果我在jtextfield中给出一个字母值，而没有使用caps lockon或shift键，那么它应该给出大写字母值。我不知道如何克服这个问题。给我一个代码来解决这个问题

Answer 1

Customized fields can easily be created by extending the model and changing the default model provided. For example, the following piece of code will create a field that holds only upper case characters. It will work even if text is pasted into from the clipboard or it is altered via programmatic changes.

 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);
         }
     }
 }

提供：JTextField

Answer 2

试一试

jtextfield.addKeyListener(new KeyAdapter(){
   keyReleased(KeyEvent e) {
      jtextfield.setText(jtextfield.getText().toUpperCase());
   }

});

Answer 3

您可以处理文本字段的on key up事件，并将文本重置为toUpperCase

textField.setText(textField.getText().toUpperCase());

这里显示了一种更好的方法

http://docs.oracle.com/javase/1.4.2/docs/api/javax/swing/JTextField.html

Answer 4

定义一个DocumentFilter并分配给JTextFiled的Document或只是扩展JTextField中使用的PlainDocument并重写insertString()方法。将字符串参数转换为大写并传递给super.insertString()