[FIXED] Check on runtime if textfield contains a number

Issue

I am trying to figure out how i can check on runtime whether a number is being entered on a textfield and i want then to execute a Backspace to delete it on its own. My code is @FXML public void onKeyTyped(KeyEvent event) { if (!(event.getText().matches("[a-z]"))) { event.consume(); } }

I dont understand why it's not working. Maybe i dont understand the concept of changing something on runtime. Any input is greatly appreciated!

Solution

you could try this (FX11 Only)

    //check if character typed is a number
    if (event.getCharacter().matches("[0-9]"))
    {
        event.consume();

        //move caret back one step as we do not want the typed digit
        //and want the caret to remain after last entered text
        textField.backward();

        //delete the typed digit
        textField.deleteNextChar();

    }

Note this uses event.getCharacter() instead of event.getText(). For me getText() is always empty,as in this link:

JavaFX KeyEvent.getText() returns empty?

Not also if you wish to go your original route of checking if it's not equal to a-z remember to account for A-Z as well. Or convert the character to lower case before checking as matches is case specific.

FX8 Only

if (event.getCharacter().matches("[0-9]"))
    {
        event.consume();

    }

Answered By - user11321608