The core grammar of the object-----OC facing the end of the love paper

A little guilty, the months of neglect, but also wasted a lot of time.

Next I read some notes about the core grammar, probably not all may be wrong, I hope you can point out.

One, dot syntax

The essence of point syntax is invocation.

For example:

Person *p = [person new];

Assign value

P.age = 10; equivalent to [P setage:10]; Call setter

Take value

int a = p.age;//is equivalent to [P age]; Call getter

Ii. Scope of member variables

Direct access to @public anywhere

@private can only be accessed directly in the object method of the current class

@protect object methods for the current class and subclass. Although protected, it has a method in the parent class in the memory sub-class

Iii. @property and @synthesiz

1. Automatically generate _age.

2. Automatic generation of _age setter and getter declarations

@property int age;//write on type and name

/* Equivalent to

-(void) Setage: (int) age;

-(int) age;*/

Represents a String

@property Nsstring*name;

Implementation of generating setter and getter methods

@synthesize age = _age;

can also be attached to write

@synthesize Age =_age,name = _name;

Note:

Generally omit @synthesize, write only @property

and the Declaration and implementation of the setter and getter are automatically generated.

Four, universal pointer ID

ID is a pointer to the general form of

id = nsobject*

ID d = [person new]

Five, the construction method

belongs to the object method, and the minus sign begins.

New complete creation of an available object

① Allocating storage space ② initialization

You are no longer using new to create objects. Change to the following method

1. Call +alloc to allocate storage space

2. Call-init to initialize

Person *p = [[Person alloc] init];

Vi. overriding construction methods

Purpose: In order for the object to be created, the member variable will have some fixed values

Overriding the-init method * * *

-(ID) init//id is designed so that any object can be called NSObject

{

Be sure to call the Init method back to Super to initialize the member variables and other properties declared in the parent class

if (self = [super init]

The following initialization is possible if the object is initialized successfully

{_age = 10;//all member variable initialization values are 10

}

Return self;//returns an object that has already been initialized

}

Vii. Custom Construction methods

Custom Construction methods:

1. Must be the object method, must start with a minus sign

2. The return value must be the ID type

3. Method names begin with Initwith

For example

@interface Person:nsobject

@property NSString *name;

@property int *age;

-(ID) Initwithname: (nsstring*) name andage: (int) age;

@implementation person

-(ID) Initwithname: (nsstring*) name andage: (int) age;

{if (self=[super init])

{_name=name;

_age=age;

}

return self;

}

int main ()

{Person *p = [[Person alloc] initwithname:@ "Rose" andage:30]

return 0;

}

The nature of the class

Use the person class to create objects of type person

Person *p = [[Person alloc] init];

Gets the in-memory class object, which is the person class object

Class C = [P class];

Can also be written as class C = [Person class];

Note:

The class itself is also an object, a class-type object, or a class object,

Create a person class object with class

Create an object of person type with person

The core grammar of the object-----OC facing the end of the love paper