CODEWITHSUNDEEP
javaswingawtjtextfieldkeyevent
user1649634
user1649634

Reputation: 1

Clear a typed character during runtime in jTextField

private void jTextField1KeyPressed(java.awt.event.KeyEvent evt) {
int x=evt.getKeyCode();
if(x>=96&&x<=105)
  {
      evt.setKeyCode(8);//Here 8 is used for Backspace key to remove the numeric character entered
  }

Int This code i want the user not to type any numeric value in jTextField but if he does so then i m trying to remove it off during runtime only.... I wrote this code but its not working as i expected it to be... Plzz Help me!!

Upvotes: 0

Views: 1224

Answers (2)

Redandwhite
Redandwhite

Reputation: 2549

While perhaps not the very best way to do it, here is one very simple way.

You can override the paintComponent() method of the JTextField like this:

JTextField textField = new JTextField(text) {

@Override
protected void paintComponent(Graphics grphcs) {
    super.paintComponent(grphcs);
    String newStr = "";
    for (char c : getText().toCharArray()) {
        if (!Character.isDigit(c)) {
            newStr += c;
        }
    }
    setText(newStr);

    }
};

Upvotes: 0

MadProgrammer
MadProgrammer

Reputation: 347204

You really should avoid KeyListeners, they are too limiting for what you are ultimately trying to achieve and you're only going to end up with a mutation exception as you try and change the fields document while the field is trying to change the document.

You really should be using a DocumentFilter, that's what it's design for.

((AbstractDocument)field.getDocument()).setDocumentFilter(new DocumentFilter() {

    @Override
    public void insertString(FilterBypass fb, int offset, String text, AttributeSet attr) throws BadLocationException {

        StringBuilder sb = new StringBuilder(64);
        for (char c : text.toCharArray()) {

            if (Character.isDigit(c)) {

                sb.append(c);

            }

        }

        fb.insertString(offset, text, attr);

    }

    @Override
    public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException {

        StringBuilder sb = new StringBuilder(64);
        for (char c : text.toCharArray()) {

            if (Character.isDigit(c)) {

                sb.append(c);

            }

        }

        fb.replace(offset, length, sb.toString(), attrs);

    }

});

This is a really basic example, there are plenty on SO.

Apart from avoiding mutation exceptions, the filter intercepts the update before it reaches the document/field, so the incoming changes won't be visible of the screen, you also capture any paste events or setText calls.

Upvotes: 2

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