OBJECTIVE-C (Protocol Protocol)

Protocol protocol

Protocol: Used to declare a method

1. Definition of the Agreement

@protocol Agreement name <NSObject>

Method declaration List ....

@end

2. How to comply with the agreement

1> Class Compliance Agreement

@interface Class Name: Parent class name < protocol name 1, protocol name 2>

@end

2> Protocol Compliance Agreement

@protocol Agreement name < Other protocol name 1, other protocol name 2>

@end

3. Keywords for method declarations in the agreement

1> @required (default)

Requires implementation, and if not implemented, a warning is issued

2> @optional

Does not require implementation, how can there be no warning

4. When defining a variable, limit the object that this variable holds to a protocol

Class name < protocol name > * variable name;

id< protocol name > variable name;

Nsobject<myprotocol> *obj;

Id<myprotocol> Obj2;

If the corresponding protocol is not followed, the compiler warns

The attributes declared in [email protected] can also be used as a limit to comply with the agreement

@property (Nonatomic, Strong) class name < protocol name > * attribute name;

@property (nonatomic, strong) id< protocol name > attribute name;

@property (nonatomic, strong) dog<myprotocol> *dog;

@property (nonatomic, strong) id<myprotocol> dog2;

6. The agreement can be defined in a separate. h file and can also be defined in a class

1> If this protocol is used only in a class, the protocol should be defined in that class

2> If this protocol is used in many classes, it should be defined in a separate file

7. Classifications can be defined in separate. h and. m files and can also be defined in the original class

1> in general, are defined in a separate file

2> defines the classification in the original class, only requires the ability to read the grammar

#import<Foundation/Foundation.h>@protocolMyProtocol <NSObject>//compliance with other agreements, the other agreement names are written in brackets < >//The default is to implement- (void) test;//declaring Methods//required need to be implemented, no implementation will only issue a warning//Optional does not need to implement@required- (void) test1;- (void) test2; @optional- (void) test3;@end/** * * * above is MyProtocol.h file *******/ #import<Foundation/Foundation.h>
@protocol MyProtocol;//can have multiple protocol <mtprotocol at the same time, myprotocol2>@interfacePerson:nsobject <MyProtocol> @property (nonatomic, strong) id<myprotocol> obj;@end/** * * * above is Person.h file *******/ #import<Foundation/Foundation.h>#import "MyProtocol.h" @inplementation person- (void) test{}- (void) test1{}- (void) test2{}@end
/******The above are person.m files***********/

#import <Foundation/Foundation.h>
#import "MtProtocol.h"
#import "Person.h"
int main ()
{

Person *p = [[Person alloc] init];
　　

return 0;
}

Base protocol:<nsobject> default adherence to the base protocol

OBJECTIVE-C (Protocol Protocol)