OC_協定實作代理委托模式

CareBabyProtocol.h檔案

//協定檔案
import <Foundation/Foundation.h>
@class Baby;
@protocol CareBabyProtocol <NSObject>
//協定中的方法
-(void)babyDontClean:(Baby *)baby;
@end
           

Baby.h檔案

import <Foundation/Foundation.h>
import "CareBabyProtocol.h"
@interface Baby : NSObject
//baby的清潔值屬性
@property(nonatomic,assign)NSInteger cleanValue;

//baby中的代理者屬性
@property(nonatomic,weak)id<CareBabyProtocol> delegate;

//重寫init方法
-(instancetype)init;

@end
           

Baby.m檔案

import "Baby.h"

@implementation Baby
-(instancetype)init{
    if(self=[super init]){
        //為cleanValue屬性賦初始值
        _cleanValue=100;

        //建立一個定時器
        [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(observeCleanValue) userInfo:nil repeats:YES];
    }
    return self;
}

//定時器不斷調用的方法
-(void)observeCleanValue{
    //清潔值每次減1
    _cleanValue--;

    if([_delegate respondsToSelector:@selector(babyDontClean:)]
   &&[_delegate conformsToProtocol:@protocol(CareBabyProtocol)]){
        //調用代理的方法
        [_delegate babyDontClean:self];
    }
}
@end
           

Nanny.h檔案

import <Foundation/Foundation.h>
import "CareBabyProtocol.h"
//保姆實作照顧小孩的協定
@interface Nanny : NSObject <CareBabyProtocol>
//保姆的屬性：小孩
@property(nonatomic,strong)Baby *baby;

@end
           

Nanny.m檔案

import "Nanny.h"
import "Baby.h"
@implementation Nanny
//保姆實作協定中的方法
-(void)babyDontClean:(Baby *)baby{
    NSInteger cleanValue=baby.cleanValue;

    //保姆監視小孩的清潔值
    NSLog(@"baby的清潔值為：%ld",cleanValue);

    //當小孩的清潔值低于95時為小孩洗澡，恢複清潔值
    if(cleanValue<95){
        NSLog(@"保姆為baby洗澡了");
        baby.cleanValue=100;
    }
}
@end
           

運作結果：