通知的使用

Main.m

#import "Children.h"
#import "Nurse.h"

int main(int argc, const char * argv[])
{

    @autoreleasepool {

        Children *children = [[Children alloc] init];

        Nurse *nurse = [[Nurse alloc] initWithChildren:children];

        [[NSRunLoop currentRunLoop] run];

        [children release];
        [nurse release];

    }
    return 0;
}

Children.h

@interface Children : NSObject

@property(nonatomic,assign)NSInteger happyValue;    //欢乐值
@property(nonatomic,assign)NSInteger hungryValue;   //饥饿值

Children.m

- (id)init {

    self = [super init];

    if (self) {
        //开启定时器
        [NSTimer scheduledTimerWithTimeInterval:1
                                         target:self
                                       selector:@selector(timeAction:)
                                       userInfo:nil
                                        repeats:YES];
        _hungryValue = 100;
        _happyValue = 100;
    }

    return self;
}

- (void)timeAction:(NSTimer *)time {

    --_hungryValue;
    --_happyValue;

    NSLog(@"happyValue:%ld",_happyValue);

    if (_happyValue < 90) {
        //通知保姆
        //发送一个通知，通知名：happlyValueNotification
        [[NSNotificationCenter defaultCenter] postNotificationName:@"happlyValueNotification" object:self];

    }

    NSLog(@"hungryValue:%ld",_hungryValue);

    if (_hungryValue < 85) {
        //发送通知
        [[NSNotificationCenter defaultCenter] postNotificationName:@"hungryValueNotification" object:self];
    }

}

Nurse.h

@class Children;

@interface Nurse : NSObject {

    Children *_children;

}

- (id)initWithChildren:(Children *)children;

Nurse.m

#import "Children.h"

@implementation Nurse

- (id)initWithChildren:(Children *)children {

    self = [super init];

    if (self) {
        _children = [children retain];

        //接收通知，通知名：happlyValueNotification
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(happlyValueChange)
                                                     name:@"happlyValueNotification"
                                                   object:nil];

        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(hungryValueChange:) name:@"hungryValueNotification" object:nil];

    }

    return self;
}

- (void)happlyValueChange {

    [self play];
}

- (void)hungryValueChange:(NSNotification *)notification {

    [self feed];

}

- (void)play {

    NSLog(@"保姆陪小孩玩耍");
    _children.happyValue = 100;

}

- (void)feed {

    NSLog(@"保姆给小孩晚饭");
    _children.hungryValue = 100;

}

- (void)dealloc {

    //移除通知
//    [[NSNotificationCenter defaultCenter] removeObserver:self name:@"happlyValueNotification" object:nil];
//    [[NSNotificationCenter defaultCenter] removeObserver:self name:@"hungryValueNotification" object:nil];

    //移除所有通知
    [[NSNotificationCenter defaultCenter] removeObserver:self];

    [_children release];

    [super dealloc];

}