In most of the iOS SDK tutorials I've read online both from Apple and elsewhere, so many instance variables are made properties, even when they are only accessed from within their own class.
E.G. in Facebook's latest iOS SDK a user is encouraged to maintain an instance of the Facebook class called facebook in the app delegate. facebook" is a property. This is then referred to throughout the sample code as "self.facebook". But the "facebook" property is not referenced anywhere from outside the app delegate.
Why is this? What am I missing? If an instance variable is only used within its own class, my inclination would be not to make it a property so that it is not publicly visible, and refer to it simply as facebook rather than self.facebook or self->facebook from within the class.
Frankly, even if I needed the facebook property, I think I'd rather refer to it within the app delegate as simply "facebook" rather than "self.facebook".
So what gives? Why am I seeing properties everywhere?
Properties don't have anything to do with whether an iVar is publicly exposed or not. Instead properties create accessors methods that manage retention and foster encapsulation.
If you want a private property just declare the ivar under the @private directive and then define the properties in the implementation file.