Question

If you tell an Objective-C object to removeObservers: for a key path and that key path has not been registered, it cracks a sad, like:

Cannot remove an observer <observerObject> for the key path "theKeyPath" from <objectbeingObserved> 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
}

Answer 1

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 an exception was thrown
}