The property in IOS Category and Protocol are you really going to do that?

First, property

Synthetic accessors:

@property format:

1 @property (modifier list) variable type variable name;

Before Xcode4.4:

@property causes the compiler to customize the generation of Set/get method declarations.

Implementation of @synthesize Auto-generated Set/get method

@synthesize also automatically generate private member variables

Xcode4.4 after:

Without having to write @synthesize, the compiler can give us the declaration and implementation of the Set/get method by @property, which generates the member variable by default: _propertyname

The member variables generated with @property are private.

When we want to change the default member variable name, @synthesize age = newName; '

If the subclass wants to access the member variables of the parent class,

1, through the Set/get method

2. Declared member variables displayed

* * Go to the chase * *

First, declare:

Category and protocol can add methods

@property keywords can be added in category and protocol

Second, about the property in protocol

When adding a property in protocol, it is actually declaring the getter and setter method, in the class that implements the protocol protocol , we have to manually add the instance variables ourselves, and we need to implement the Setter/getter method

Pseudo code:

Main.m

1 Student *student = [[Student alloc] init]; 2         3 @" Daddy Peng " ; 4         5 NSLog (@ "%@", student.name); 6         

Person.h

Set the protocol, with which the property

1 //2 //Person.h3 //Categories and agreements4 //5 //Created by Ma C on 16/5/19.6 //copyright©2016 year Pengsheng rime. All rights reserved.7 //8 9 #import<Foundation/Foundation.h>Ten  One @protocolPersondelegate <NSObject> A  -@property (nonatomic, copy) NSString *name; -  the @end -  - @interfacePerson:nsobject -  + @end

Student.h

Generating member variables, _name

1 //2 //PersonSon.h3 //Categories and agreements4 //5 //Created by Ma C on 16/5/19.6 //copyright©2016 year Pengsheng rime. All rights reserved.7 //8 9 #import<Foundation/Foundation.h>Ten #import "Person.h" One  A @interfaceStudent:nsobject <personDelegate> - { -     //* * * DECLARE member Variable * * * theNSString *_name; - } -  -  + @end

Student.m

Here are two ways to do this, one is to automatically implement Setter/gerter, a manual setter/gerter

1 //2 //personson.m3 //Categories and agreements4 //5 //Created by Ma C on 16/5/19.6 //copyright©2016 year Pengsheng rime. All rights reserved.7 //8 9 #import "Student.h"Ten  One @implementationStudent A  - //------------------Automatic----------------------// - //@synthesize the // - //during the compiler, let the compiler automatically generate the Getter/setter method.  - // - //custom masks automatically generate this method when there is a custom save or Fetch method +  - //automatic generation of Setter/getter methods +  A //@synthesize name; at  -  -  - //------------------Manual----------------------// -  - //@dynamic in // - //tells the compiler not to automatically generate Getter/setter methods to avoid warnings during compilation to // + //then implement the access method by yourself -  the //Set method that implements the property defined in person name *- (void) SetName: (NSString *) name { $_name =name;Panax Notoginseng      - } the  + //get method that implements the property defined in person name A-(NSString *) name { the     return_name; + } -  $ @end

Print log logs as:

Explain the basic function of successful implementation of property, and can implement assignment and value operation

Third, the property in category

When adding a property in the category, when adding getter and setter methods in @implentation, the category cannot add an instance variable

1) Use temporary global variables to override member variables

First declare: person does not have a name attribute

Main.m

Import Header file:

#import "Person+extension.h"

1 person *person = [[Person alloc] init]; 2         3 @" Peng " ; 4         5 NSLog (@ "%@", Person.name);

Person+extension.h

1 //2 //Person+extension.h3 //Categories and agreements4 //5 //Created by Ma C on 16/5/19.6 //copyright©2016 year Pengsheng rime. All rights reserved.7 //8 9 #import "Person.h"Ten  One @interfacePerson (Extension) A  -@property (nonatomic, strong) NSString *name; -  the @end

Person+extension.m

1 //2 //person+extension.m3 //Categories and agreements4 //5 //Created by Ma C on 16/5/19.6 //copyright©2016 year Pengsheng rime. All rights reserved.7 //8 9 #import "Person+extension.h"Ten #import<objc/runtime.h> One  A //* * * TEMP Variable * * * - StaticNSString *_name; -  the @implementationPerson (Extension) -  -- (void) SetName: (NSString *) name { -_name =name; + } -  +-(NSString *) name { A     return_name; at } - @end

2) Implementing member variables using Runtime association objects

In addition to person+extension.m the other is consistent with the first method

Runtime Person+extension.m

1 @implementationPerson (Extension)2 3- (void) SetName: (NSString *) name{4 Objc_setassociatedobject (self, @selector (name), name,objc_association_retain_nonatomic);5 }6 7-(NSString *) name{8     9NSString *n =Objc_getassociatedobject (self, @selector (name));Ten     returnN; One}

The two ways to print log logs are the same, as:

The property in IOS Category and Protocol are you really going to do that?