04 2012 档案

摘要：A class extension allows you to declare a method that is private to the classsee “Extensions” in The Objective-C Programming Language). 阅读全文

摘要：Verify Object Capabilities at RuntimeIntrospection, a powerful and useful feature of Objective-C and the NSObject class, enables you to learn certain things about objects at runtime. You can thus avoid mistakes in your code such as sending a message to an object that doesn’t recognize it or assuming 阅读全文

摘要：（-）An instance method is a method whose execution is scoped to a particular instance of the class. In other words, before you call an instance method, you must first create an instance of the class. Instance methods are the most common type of method.（+）A class method is a method whose execution is 阅读全文