Hi all,
I'm stuck
I have implemented a very basic app. It is based on Chap 7 of Hillegass.
A slider, two textFields, and a couple of buttons. Bascially, the the slider's value, the textField's value are bound to a number(fido) in a userDefined Controller(AppController). This works as expected...the slider causes the textField to update.
The first button initiates KVO in the second textField.
Now, **this** works. ( this is the method in the startKVOButton)
And is implemented thus;
Here is my question. Hillegass seems to imply that one can take an object eg a text field and specify that the text field **alone** register itself as an observer
However, if I try and implement this in the above methods, for example change the line of code from
to
**where textField is an outlet of AppController, suitable linked in IB to the second textField**
I get an error thus
Which leads me to ask this.
Is a control in of itself not an object? Or am I trying to do something that is simply not possible?
Thanks in advance.
I'm stuck
I have implemented a very basic app. It is based on Chap 7 of Hillegass.
A slider, two textFields, and a couple of buttons. Bascially, the the slider's value, the textField's value are bound to a number(fido) in a userDefined Controller(AppController). This works as expected...the slider causes the textField to update.
The first button initiates KVO in the second textField.
Now, **this** works. ( this is the method in the startKVOButton)
Code:
[ self addObserver:(NSObject *) self forKeyPath:(NSString *) @"fido"
options:(NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld)
context: @"Starting KVO"];
Code:
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
NSLog(@"keyPath:%@\n Object: %@\n change: %@:", keyPath, object, change);
if ( [ keyPath isEqual:@"fido"])
[textField setObjectValue: [change objectForKey: NSKeyValueChangeNewKey]];
/* NSLog(@"%@", context); */
}Here is my question. Hillegass seems to imply that one can take an object eg a text field and specify that the text field **alone** register itself as an observer
However, if I try and implement this in the above methods, for example change the line of code from
Code:
self addObserver:(NSObject *) self
Code:
self addObserver:(NSObject *) textFieldI get an error thus
Which leads me to ask this.
Is a control in of itself not an object? Or am I trying to do something that is simply not possible?
Thanks in advance.