Getting started with iOS development☞OC Language & #183; note 7, iosoc

Getting started with iOS development☞OC language · note 7, iosoc
Category

Categories can only be added to class extension methods. Attributes cannot be added!

@ Interface Class Name (category name) // Declare the Extension Method @ End

@ Implementation Class Name (category name) // Method for implementing Expansion @ End

Create a category:

Classification considerations:

• A category is used to add methods to the original class. It can only add methods, but cannot add attributes (member variables)
• Define the @ property attribute in the category. Only the declaration of the setter/getter method is generated, and the implementation of the method and instance variables are not generated.
• You can access the attributes in. h of the original class in the category.

Call Sequence of methods: 1. Category> 2. Category> 3. parent class

Extended Extension

Anonymous classification defines extensions in the. m file of the class, and defines private attributes and private methods in extensions.

@ Interface Class Name () // Declare private member variables // Declare private attributes // Declare a private Method @ End

• The most common extension method is:

Define extensions in the. m file of the class, define private attributes in extensions, and declare private methods.

You can use extensions in the UI to define private attributes!

Category exercise: