Dark Horse programmer-------Objective-c Basics 4

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1. Strong pointer: By default all pointers are strong pointers, keyword __strong

Weak pointers: __week keyword-decorated pointers

2.ARC: The compiler will automatically insert retain, release, Autorelease, where the code is appropriate

ARC's judgment rule, as long as no strong pointer to the object, the object will be released

3. Determine if it is an arc

View project information; Cannot use retain, release, Autorelease, Retaincount, cannot use [super Dealloc] in Dealloc method

Create objects normally without manually releasing objects

4.ARC the problem that the loop introduces, the solution one end uses a weak pointer with a strong pointer

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Strong strong pointer

Week weak pointer

6.__week person *p=[[person alloc]init];//unreasonable, the object once created is released, the object is released, ARC set the pointer to nil

7. The use of classification, the method of extending the original class

#import " Student.h " @interface Student (study)-(void) run; @end

#import " Student+study.h " @implementation Student (study)-(void) run{    NSLog (@ "study run" );} @end

The methods used in the classification are the same as the original methods, and if the classification is the same as the method name in the class, the method of calling the classification is preferred.

8. Informal agreements

The so-called informal agreement is the category, that is, the categories of nsobject or its subclasses, are informal agreements

9. Extensions-Special classification

The class name is empty, and you can add instance variables and methods to classes, but the method must be implemented in the. m file of the class itself

Variables and methods are equivalent to private

Definition of 10.block

Int (^myblock) (int,int) =^ (int a,int b) {};

Call Mode:

(Myblock);

You can assign a value to Myblock again.

22.typedef Bolck

typedef int (^myblock) (int,int) =^ (int a,int b) {};

Myblock Myblock1,myblock2;

External variables can be accessed within 23.block

When the block is defined, the block copies the value of the external variable in a const manner and places it in the memory of the block and cannot be modified

Global variables can be modified

External variable plus __block then the block is no longer copied in a const manner, it can be modified inside the block, and in the later code, all of the heap space is used

24.block application scenario, passing code blocks as parameters

or block as the return value

25. Mnemonic Inlineblock

26.protocol is a Java-like excuse, but not all of the methods in the protocol must be implemented

Steps:

Defining protocols

@protocol Agreement name <NSObject>

@end

Adoption Agreement

@interface Person:nsobject < protocol 1, Protocol 2>

@end

Ways to Implement Protocols

When an agreement is adhered to, there is a declaration of all the methods in this agreement.

The agreement may also comply with other agreements

OC cannot inherit multiple classes, but can comply with multiple protocols

Modifiers for 27.protocol methods

Must implement @required

Choose to implement @optional

28.id type after add < protocol name > indicates that only objects that have complied with the protocol are assigned

The class name is appended to the < protocol name > indicates that only the object that follows the protocol's current class is assigned

29. Protocol Proxy Mode

The incoming object, in place of the current class, completes a function called the proxy mode

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Replace import importing protocol with @protocol protocol name in. h file

Import protocols in. m files

Import protocol when re-use in main file

Dark Horse programmer-------Objective-c Basics 4