How to create KVO for a TextField [Mac OS]?

Question

I need to create KVO for TextField1 and when changing its value transfer value of TextField1 to TextFiled2. I tried so:

//.h
@property (weak) IBOutlet NSTextFieldCell *text1;
@property (weak) IBOutlet NSTextFieldCell *text2;

//.m
-(id) init
{
    self = [super init];
    if (self)
    {
        [self addObserver:self forKeyPath: @"text1" options:NSKeyValueObservingOptionOld context:nil];
    }
    return self;
}

-(void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    [self.text2 setStringValue:[self.text1 stringValue]];
}

It does not work. Where is a mistake?

Answer 1

As it stands, you're observing changes in the text1 property, and not it's stringValue, and even then that only works when setStringValue: is called explicitly (it isn't called by the input context for the field). You'd be better off becoming it's delegate and implementing controlTextDidChange:, rather than trying to KVO the thing.