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  • IOS Tutorial 1) ObjectiveC Basics

    Objects and classes
    A class consists primarily of two things: variables that can store data and methods
    that can perform operations.

    Subclasses
    Classes can also inherit functionality from an existing class

    Instance and class variables

    Changing the value of an instance variable in one object
    will not affect the value of the same variable in all the other objects of that class.
    Conversely, only a single copy of a class variable exists. If you change the value of
    a class variable from one object, the value of that variable will change for all the
    objects of that class

    Accessor methods
    Accessor methods, sometimes called getters and setters, are usually fairly simple
    methods used to get and set instance variables in a class

    Class methods
    Class methods (also known as static methods) are  methods that are associated directly

    with the class rather than the object instance

    Events and messages
    An event is a message generated by the user interacting with your application’s
    controls. For instance, if you tap the screen of your iOS device, this generates a UI
    event in your application that is passed via a message from the application to an
    object that has been delegated to deal with that specific type of event

    Protocols
    A protocol definition declares methods that any class can implement. If your class
    declares that it abides by a particular protocol definition, you are announcing that
    you have implemented the minimum mandatory methods declared in the protocol
    definition, and may optionally have implemented some nonmandatory methods

    Delegate classes
    A delegate class is a class that implements a protocol for handling events.

    Event loop
    The main event loop is the principal control loop for your application.

    Reference Counting

    Reference counting is a form of garbage collection, which counts the number of references
    to an object (or portion of memory) and frees the associated memory when the
    number of references reaches zero. The main advantage of reference counting over
    "classic" garbage collection is that memory is freed as soon as it is no longer in use

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  • 原文地址:https://www.cnblogs.com/davidgu/p/3129589.html
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