Openeim When you create a new class, we all choose Cocoa class.

Source: Openeim When you create a new class, we all choose Cocoa class.

Openeim Why do we choose Cocoa class when we create a new class in the content mentioned earlier? What is cocoa?
Cocoa is not a programming language (it can run multiple programming languages), nor is it a development tool (we can still develop cocoa programs via the command line), which is a native object-oriented API for creating Mac OS X and iOS programs,Openeim Provides a programming environment for both applications.
We are often referred to as the "Cocoa framework", in fact the cocoa itself is a set of frames, which contains a number of sub frames, the most important of which are "Foundation" and "Uikit". The former is the basis of the framework, and interface-independent, which contains a large number of commonly used APIs, the latter is the basic UI class library, we will often use in the development of iOS. The position of these two frames in the system is as follows:
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In fact, all Mac OS x and iOS programs are composed of a large number of objects, and the root objects of these objects are nsobject,nsobject in the foundation framework, the specific class structure is as follows:
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Usually we will divide them into several categories:
Value Objects Collection operating system services: File systems, URLs, process communication notification archiving and serialization expressions and conditional judgments OBJECTIVE-C language Services