Restrict NSTextField input to numeric only? NSNumberformatter

Question

I\'m just getting started up with Mac App Development and so far everything is good well, I\'m just having problems trying to get a NSTextField to only accept numbers for th

Answer 1

Rather than subclassing anything, you can do it with an NSControlTextEditingDelegate method in your view controller. Set the delegate field of the NSTextField you want to check and then do something like the following in a controlTextDidChange: function which gets called on each character typed. Don't forget to initialize self.lastValidTimestampCount in this case. This function uses RegExLite to check the value, which may include commas.

// Make sure the user has typed a valid number so far.
- (void)controlTextDidChange:(NSNotification *)obj
{
    if (obj.object == self.timestampsCount)
    {
        NSString *countValue = timestampsCount.stringValue;
        if (! [countValue isMatchedByRegex:@"^[\\d\\,]{1,6}$"])
        {
            timestampsCount.stringValue = self.lastValidTimestampCount;
            NSBeep();
        }
        else
            self.lastValidTimestampCount = timestampsCount.stringValue;
    }
}