key-value-observing

I've looked on SO for examples of using Key Value Observing with an NSArray (or NSMutableArray ) and apparently you need to use an NSArrayController (which unlike KVO I'm not familiar with), but I haven't found concrete examples of how to do this. Can anyone explain with some sample code? For instance, if I have a GameModel which represents its player names with an NSArray (playerNameArray) of NSStrings . I want to observe those strings (the view controller observes the model's data) to update various things in the view. How do I get notification that the player name array has changed? EDIT :

if you tell an objective c object to removeObservers: for a key path and that key path has not been registered, it cracks the sads. like - 'Cannot remove an observer for the key path "theKeyPath" from because it is not registered as an observer.' is there a way to determine if an object has a registered observer, so i can do this if (object has observer){ remove observer } else{ go on my merry way } Adam Put a try catch around your removeObserver call @try{ [someObject removeObserver:someObserver forKeyPath:somePath]; }@catch(id anException){ //do nothing, obviously it wasn't attached because

I am trying to get key-value-observing to work for an NSMutableArray. Below is the .h file for MyObservee, the observed class: @interface MyObservee : NSObject { @private int someValue; @private NSMutableArray *someArray; } @property (readwrite,assign) int someValue; - (NSMutableArray *)someArray; @end The class MyObserver implements observeValueForKeyPath:ofObject:change:context:. Here is how I add the observer: MyObservee *moe = [[MyObservee alloc] init]; MyObserver *mobs = [[MyObserver alloc] init]; [moe addObserver:mobs forKeyPath:@"someArray" options:(NSKeyValueObservingOptionNew |