OC-Protocol Protocol

@protocol MyProtocol <NSObject>//Base agreement

@required//Declares what must be done, by default

@required

-(void) walk;

-(void) speak;

-(void) think; Think is not implemented in the class implementation warns!!!

@optional

-(void) sing;

-(void) laugh;

@end

A protocol can declare a large stack of methods, but cannot declare member variables;

Two agreements can not inherit, but the agreement may abide by another agreement;

Subclasses can abide by the agreement of the parent class;

nsobject<myprotocol,allprotocol> * stu = [[Student alloc]init];

Equivalent to

Student *stu = [[Student alloc]init];//any class

[Stu Eat]; Subclass overrides, calling the subclass's

[Stu Run]; Subclass not rewritten, find method of parent class up

Student can Eat

Person can run

Program ended with exit code:0

Student * stu = [[Student alloc]init];

Student <myProtocol> * Student = stu;

nsobject<myprotocol> * student = Stu;

id<myprotocol> student = Stu;

If an error is detected, the STU is not complying with the agreement.

#import "Student.h"

@implementation Student

-(void) exam{

NSLog (@ "Student can exam.");

}

-(void) eat{

NSLog (@ "Student can Eat");

}

@end

#import <Foundation/Foundation.h>

@protocol Allprotocol <NSObject>

-(void) eat;

-(void) run;

@end

#import "Person.h"

@implementation person

-(void) eat{

NSLog (@ "person can eat");

}

-(void) run{

NSLog (@ "person can run");

}

@end

OC-Protocol Protocol