Java for UpperCase

Question

点击这里显示gif

DocumentFilter df = new DocumentFilter(){
@Override
 public void insertString(DocumentFilter.FilterBypass fb, int offset,String string, AttributeSet attr) throws BadLocationException {
     super.insertString(fb, offset, string.toUpperCase(), attr);
 }

 @Override
 public void replace(DocumentFilter.FilterBypass fb, int offset, int length,String text, AttributeSet attrs) throws BadLocationException {
     super.insertString(fb, offset, text.toUpperCase(), attrs);
 }
};  


txtCognome.setText("");
documentCognome.setDocumentFilter(dff);

问题是当我选择文本并重新键入时，选择的文本不会被删除，而是保留(查看顶部的gif )。

Answer 1

public void replace(DocumentFilter.FilterBypass fb, int offset, int length,String text, AttributeSet attrs) throws BadLocationException {
     super.insertString(fb, offset, text.toUpperCase(), attrs);

您应该调用super.replace(...)，因为您正在重写replace()方法。

Answer 2

CustomLengthTextField textField = new CustomLengthTextField(-1, true);

自定义TextField

import java.awt.KeyboardFocusManager;
import javax.swing.InputVerifier;
import javax.swing.JTextField;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;
import javax.swing.text.DocumentFilter.FilterBypass;

/**
 *
 * @author Igor
 */
public class CustomLengthTextField extends JTextField {

    protected boolean upper = false;
    protected int maxlength = 0;

    public CustomLengthTextField() {
        this(-1);
    }

    public CustomLengthTextField(int length, boolean upper) {
        this(length, upper, null);
    }

    public CustomLengthTextField(int length, InputVerifier inpVer) {
        this(length, false, inpVer);
    }

    /**
     *
     * @param length - maksimalan length
     * @param upper - turn it to upercase
     * @param inpVer - InputVerifier
     */
    public CustomLengthTextField(int length, boolean upper, InputVerifier inpVer) {
        super();
        this.maxlength = length;
        this.upper = upper;
        if (length > 0) {
            AbstractDocument doc = (AbstractDocument) getDocument();
            doc.setDocumentFilter(new DocumentSizeFilter());
        }
        setInputVerifier(inpVer);
    }

    public CustomLengthTextField(int length) {
        this(length, false);
    }

    public void setMaxLength(int length) {
        this.maxlength = length;
    }

    class DocumentSizeFilter extends DocumentFilter {

        public void insertString(FilterBypass fb, int offs, String str, AttributeSet a)
                throws BadLocationException {

            //This rejects the entire insertion if it would make
            //the contents too long. Another option would be
            //to truncate the inserted string so the contents
            //would be exactly maxCharacters in length.
            if ((fb.getDocument().getLength() + str.length()) <= maxlength) {
                super.insertString(fb, offs, str, a);
            }
        }

        public void replace(FilterBypass fb, int offs,
                int length,
                String str, AttributeSet a)
                throws BadLocationException {

            if (upper) {
                str = str.toUpperCase();
            }

            //This rejects the entire replacement if it would make
            //the contents too long. Another option would be
            //to truncate the replacement string so the contents
            //would be exactly maxCharacters in length.
            int charLength = fb.getDocument().getLength() + str.length() - length;

            if (charLength <= maxlength) {
                super.replace(fb, offs, length, str, a);
                if (charLength == maxlength) {
                    focusNextComponent();
                }
            } else {
                focusNextComponent();
            }
        }

        private void focusNextComponent() {
            if (CustomLengthTextField.this == KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner()) {
                KeyboardFocusManager.getCurrentKeyboardFocusManager().focusNextComponent();
            }
        }
    }
}