iOS设计模式 (七) 协议模式

非正式协议

• 非正式协议就是类别，即凡是NSObject或其子类的类别，都是非正式协议。

协议（protocol）

• 简单的说就是声明一些方法写到.h中（方法有2种，一是必须实现，二是选择实现）

协议的作用

• 供其他的类去遵守，如果一个类遵守了一个协议，就应该实现这个协议中定义的必须要实现的方法

协议的声明

#import <Foundation/Foundation.h>

@protocol PersonProtocol <NSObject>

- (NSInteger )accpetSpeeds;
@end

协议的使用

#import "ViewController.h"
#import "PersonProtocol.h"

@interface ViewController ()<PersonDelegate>
@end

协议代理的demo实例

• PersonProtocol

#import <Foundation/Foundation.h>

@protocol PersonProtocol <NSObject>

- (NSInteger )accpetSpeeds;

@end

• Model 类

@interface Model : NSObject

- (NSInteger )accpetSpeeds;

@end

#import "Model.h"
#import "PersonProtocol.h"

@interface Model ()<PersonProtocol>

@end

@implementation Model

- (NSInteger )accpetSpeeds
{
    return 100.f;
}

@end

• Person

#import <Foundation/Foundation.h>

@class Person;

@protocol PersonDelegate <NSObject>

- (void)personRun:(Person *)person speeds:(NSInteger)speeds;
@end

@interface Person : NSObject

@property (nonatomic, weak)id <PersonDelegate>delegate;

- (void)run:(NSInteger)speeds;

@end
#import "Person.h"

@implementation Person

- (void)run:(NSInteger)speeds
{
    
    if (self.delegate && [self.delegate respondsToSelector:@selector(personRun:speeds:)]) {
        [self.delegate personRun:self speeds:0.5];
    }
    
}
@end

• ViewController

#import "ViewController.h"
#import "Person.h"
#import "PersonProtocol.h"
#import "Model.h"

@interface ViewController ()<PersonDelegate>
@property (nonatomic, assign)NSInteger age;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    Person *p = [[Person alloc] init];
    p.delegate = self;
    [p run: 50];
    
    Model *mode = [Model new];
    id <PersonProtocol> object = mode;
    [self testData:object];
    
}

- (void)personRun:(Person *)person speeds:(NSInteger)speeds
{
    NSLog(@"speeds====:%ld",speeds);
}



- (void)testData:(id<PersonProtocol>)model
{
    self.age  = [model accpetSpeeds];
    NSLog(@"self.age ===:%ld",self.age);
}

@end

• demo地址：https://github.com/defuliu/DelegateProtocolPattern.git