Re: text field numbers only

click on the text field and change the keyboard type from the right panel

You can also use controlTextDidChange

    override func controlTextDidChange(obj: NSNotification) {

        let object = obj.object as! NSTextField

        if object !== cellTextField { return } /

        someCellTextFieldHasChanged = true /

        let lastChar = object.stringValue.count - 1         /

        guard let typed = object.stringValue.lastChar else { return }   /

        if !"0123456789".containsChar(typed) {

            cellTextField!.stringValue = cellTextField!.stringValue[0..<lastChar]

        }

    }

ShinehahGnolaum wrote:

How do I force the user to enter only numbers in a text field?

What platform are you working on?  So far you’ve got one iOS answer and one macOS answer!

Can you be more precise about what you mean by “numbers”.  Are you looking to filter out everything that’s not a digit?  Or do you want to handle things like decimal points?  And do you want to force the user to use Western Arabic digits?  Or will you accept other digits (for example, Eastern Arabic digits)?

toshb wrote:

click on the text field and change the keyboard type from the right panel

This is a good idea but be aware that it doesn’t prevent the user from entering text via other means (most notably, via Paste).  You can catch other modifications via the -shouldChangeTextInRange:replacementText: callback.

Also, if you want to force Western Arabic digits you’ll want to use ASCII Capable Number Pad (UIKeyboardTypeASCIICapableNumberPad) rather than Number Pad (UIKeyboardTypeNumberPad).

Claude31 wrote:

if !"0123456789".containsChar(typed) {
  cellTextField!.stringValue = cellTextField!.stringValue[0..<lastChar]
}

Two things:

• This assumes the user is using Western Arabic digits.

• On macOS, you may be better off attaching a number formatter to your text field.  You can set that up in IB or via the formatter of the text field cell.

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In the case of UITextField, you would want to implement the textField(_:shouldChangeCharactersIn:replacementString:) delegate, then filter out the characters you don't want in the input.

If you only want decimal characters, you could use NSCharacterSet's decimalDigits and filter out characters not present in that set.