ReactiveCocoa 用法实例

 

我个人非常推崇ReactiveCocoa，它就像中国的太极，太极生两仪，两仪生四象，四象生八卦，八卦生万物。ReactiveCocoa是一个高度抽象的编程框架，它真的很抽象，初看你不知道它是要干嘛的，等你用上了之后，就发现，有了它你是想干嘛就干嘛，编码从未如此流畅。

在此我不会讲ReactiveCocoa的原理，因为不能讲明白的才叫抽象。我也不会提及相关概念。我只是让你看看我用着它是有多爽。

代码的四十八手

察值

你别动，你一动我就知道。

 

 

 

 

 

Objective-C

 

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@weakify(self); [RACObserve(self, value) subscribeNext:^(NSString* x) {     @strongify(self);     NSLog(@"你动了"); }];

单边

你唱歌，我就跳舞。

textField的内容长度隐射成BOOL值，绑定到confirmButton的enable属性上面，当textField输入内容不为空的时候，confirmButton的enable = YES。

 

 

 

 

 

 

Objective-C

 

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RACSignal *signalA = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"唱歌"];         [subscriber sendCompleted];         return nil;     }];     RAC(self, value) = [signalA map:^id(NSString* value) {         if ([value isEqualToString:@"唱歌"]) {             return @"跳舞";         }         return @"";     }];

双边

你向西，他就向东，他向左，你就向右。

 

 

 

 

 

Objective-C

 

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RACChannelTerminal *channelA = RACChannelTo(self, valueA);     RACChannelTerminal *channelB = RACChannelTo(self, valueB);     [[channelA map:^id(NSString *value) {         if ([value isEqualToString:@"西"]) {             return @"东";         }         return value;     }] subscribe:channelB];     [[channelB map:^id(NSString *value) {         if ([value isEqualToString:@"左"]) {             return @"右";         }         return value;     }] subscribe:channelA];     [[RACObserve(self, valueA) filter:^BOOL(id value) {         return value ? YES : NO;     }] subscribeNext:^(NSString* x) {         NSLog(@"你向%@", x);     }];     [[RACObserve(self, valueB) filter:^BOOL(id value) {         return value ? YES : NO;     }] subscribeNext:^(NSString* x) {         NSLog(@"他向%@", x);     }];     self.valueA = @"西";     self.valueB = @"左";

 

 

 

 

 

Objective-C

 

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2015-08-15 20:14:46.544 Test[2440:99901] 你向西   2015-08-15 20:14:46.544 Test[2440:99901] 他向东   2015-08-15 20:14:46.545 Test[2440:99901] 他向左   2015-08-15 20:14:46.545 Test[2440:99901] 你向右

代理

你是程序员，你帮我写个app吧。

 

 

 

 

 

Objective-C

 

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@protocol Programmer <NSObject> - (void)makeAnApp; @end

 

 

 

 

 

Objective-C

 

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RACSignal *ProgrammerSignal =   [self rac_signalForSelector:@selector(makeAnApp)                fromProtocol:@protocol(Programmer)]; [ProgrammerSignal subscribeNext:^(RACTuple* x) {     NSLog(@"花了一个月，app写好了"); }]; [self makeAnApp];

 

 

 

 

 

Objective-C

 

1	2015-08-15 20:46:45.720 Test[2817:114564] 花了一个月，app写好了

广播

知道你的频道，我就能听到你了。

 

 

 

 

 

 

Objective-C

 

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[[[NSNotificationCenter defaultCenter] rac_addObserverForName:@"代码之道频道" object:nil] subscribeNext:^(NSNotification* x) {         NSLog(@"技巧：%@", x.userInfo[@"技巧"]);     }];     [[NSNotificationCenter defaultCenter] postNotificationName:@"代码之道频道" object:nil userInfo:@{@"技巧":@"用心写"}];

 

 

 

 

 

Objective-C

 

1	2015-08-15 20:41:15.786 Test[2734:111505] 技巧：用心写

连接

生活是一个故事接一个故事。

 

 

 

 

 

 

Objective-C

 

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RACSignal *signalA = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"我恋爱啦"];         [subscriber sendCompleted];         return nil;     }];     RACSignal *signalB = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"我结婚啦"];         [subscriber sendCompleted];         return nil;     }];     [[signalA concat:signalB] subscribeNext:^(id x) {         NSLog(@"%@",x);     }];

 

 

 

 

 

Objective-C

 

1 2	2015-08-15 12:19:46.707 Test[1845:64122] 我恋爱啦   2015-08-15 12:19:46.707 Test[1845:64122] 我结婚啦

合并

污水都应该流入污水处理厂被处理。

 

 

 

 

 

 

Objective-C

 

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RACSignal *signalA = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"纸厂污水"];         return nil;     }];     RACSignal *signalB = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"电镀厂污水"];         return nil;     }];     [[RACSignal merge:@[signalA, signalB]] subscribeNext:^(id x) {         NSLog(@"处理%@",x);     }];

 

 

 

 

 

Objective-C

 

1 2	2015-08-15 12:10:05.371 Test[1770:60147] 处理纸厂污水   2015-08-15 12:10:05.372 Test[1770:60147] 处理电镀厂污水

组合

你是红的，我是黄的，我们就是红黄的，你是白的，我没变，我们是白黄的。

 

 

 

 

 

 

Objective-C

 

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RACSignal *signalA = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"红"];         [subscriber sendNext:@"白"];         return nil;     }];     RACSignal *signalB = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"白"];         return nil;     }];     [[RACSignal combineLatest:@[signalA, signalB]] subscribeNext:^(RACTuple* x) {         RACTupleUnpack(NSString *stringA, NSString *stringB) = x;         NSLog(@"我们是%@%@的", stringA, stringB);     }];

 

 

 

 

 

Objective-C

 

1 2	2015-08-15 12:14:19.837 Test[1808:62042] 我们就是红黄的   2015-08-15 12:14:19.837 Test[1808:62042] 我们是白黄的

压缩

你是红的，我是黄的，我们就是红黄的，你是白的，我没变，哦，那就等我变了再说吧。

 

 

 

 

 

 

Objective-C

 

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RACSignal *signalA = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"红"];         [subscriber sendNext:@"白"];         return nil;     }];     RACSignal *signalB = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"白"];         return nil;     }];     [[signalA zipWith:signalB] subscribeNext:^(RACTuple* x) {         RACTupleUnpack(NSString *stringA, NSString *stringB) = x;         NSLog(@"我们是%@%@的", stringA, stringB);     }];

 

 

 

 

 

Objective-C

 

1	2015-08-15 20:34:24.274 Test[2660:108483] 我们是红白的

映射

我可以点石成金。

 

 

 

 

 

 

Objective-C

 

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RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"石"];         return nil;     }] map:^id(NSString* value) {         if ([value isEqualToString:@"石"]) {             return @"金";         }         return value;     }];     [signal subscribeNext:^(id x) {         NSLog(@"%@", x);     }];

 

 

 

 

 

Objective-C

 

1	2015-08-16 20:00:12.853 Test[740:15871] 金

归约

糖加水变成糖水。

 

 

 

 

 

 

Objective-C

 

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RACSignal *sugarSignal = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"糖"];         return nil;     }];     RACSignal *waterSignal = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"水"];         return nil;     }];     [[RACSignal combineLatest:@[sugarSignal, waterSignal] reduce:^id (NSString* sugar, NSString*water){         return [sugar stringByAppendingString:water];     }] subscribeNext:^(id x) {         NSLog(@"%@", x);     }];

 

 

 

 

 

Objective-C

 

1	2015-08-16 20:07:00.356 Test[807:19177] 糖水

过滤

未满十八岁，禁止进入。

 

 

 

 

 

 

Objective-C

 

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[[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@(15)];         [subscriber sendNext:@(17)];         [subscriber sendNext:@(21)];         [subscriber sendNext:@(14)];         [subscriber sendNext:@(30)];         return nil;     }] filter:^BOOL(NSNumber* value) {         return value.integerValue >= 18;     }] subscribeNext:^(id x) {         NSLog(@"%@", x);     }];

 

 

 

 

 

Objective-C

 

1 2	2015-08-16 20:11:20.071 Test[860:21214] 21   2015-08-16 20:11:20.071 Test[860:21214] 30

扁平

打蛋液，煎鸡蛋，上盘。

 

 

 

 

 

 

Objective-C

 

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[[[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         NSLog(@"打蛋液");         [subscriber sendNext:@"蛋液"];         [subscriber sendCompleted];         return nil;     }] flattenMap:^RACStream *(NSString* value) {         return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {             NSLog(@"把%@倒进锅里面煎",value);             [subscriber sendNext:@"煎蛋"];             [subscriber sendCompleted];             return nil;         }];     }] flattenMap:^RACStream *(NSString* value) {         return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {             NSLog(@"把%@装到盘里", value);             [subscriber sendNext:@"上菜"];             [subscriber sendCompleted];             return nil;         }];     }] subscribeNext:^(id x) {         NSLog(@"%@", x);     }];

 

 

 

 

 

Objective-C

 

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2015-08-16 20:39:34.786 Test[1226:34386] 打蛋液   2015-08-16 20:39:34.787 Test[1226:34386] 把蛋液倒进锅里面煎   2015-08-16 20:39:34.787 Test[1226:34386] 把煎蛋装到盘里   2015-08-16 20:39:34.787 Test[1226:34386] 上菜

秩序

把大象塞进冰箱只需要三步：打开冰箱门，把大象塞进冰箱，关上冰箱门。

 

 

 

 

 

 

Objective-C

 

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[[[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         NSLog(@"打开冰箱门");         [subscriber sendCompleted];         return nil;     }] then:^RACSignal *{        return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {            NSLog(@"把大象塞进冰箱");            [subscriber sendCompleted];            return nil;        }];     }] then:^RACSignal *{         return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {             NSLog(@"关上冰箱门");             [subscriber sendCompleted];             return nil;         }];     }] subscribeCompleted:^{         NSLog(@"把大象塞进冰箱了");     }];

 

 

 

 

 

Objective-C

 

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2015-08-16 20:45:27.724 Test[1334:37870] 打开冰箱门   2015-08-16 20:45:27.725 Test[1334:37870] 把大象塞进冰箱   2015-08-16 20:45:27.725 Test[1334:37870] 关上冰箱门   2015-08-16 20:45:27.726 Test[1334:37870] 把大象塞进冰箱了

命令

我命令你马上投降。

 

 

 

 

 

 

Objective-C

 

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RACCommand *aCommand = [[RACCommand alloc] initWithSignalBlock:^RACSignal *(id input) {        return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {            NSLog(@"我投降了");            [subscriber sendCompleted];            return nil;        }];     }];     [aCommand execute:nil];

 

 

 

 

 

Objective-C

 

1	2015-08-16 20:54:32.492 Test[1450:41849] 我投降了

延迟

等等我，我还有10秒钟就到了。

 

 

 

 

 

Objective-C

 

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[[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         NSLog(@"等等我，我还有10秒钟就到了");         [subscriber sendNext:nil];         [subscriber sendCompleted];         return nil;     }] delay:10] subscribeNext:^(id x) {         NSLog(@"我到了");     }];

 

 

 

 

 

Objective-C

 

1 2	2015-08-16 21:00:57.622 Test[1619:45924] 等等我，我还有10秒钟就到了   2015-08-16 21:01:07.624 Test[1619:45924] 我到了

重放

一次制作，多次观看。

 

 

 

 

 

 

Objective-C

 

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RACSignal *replaySignal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         NSLog(@"大导演拍了一部电影《我的男票是程序员》");         [subscriber sendNext:@"《我的男票是程序员》"];         return nil;     }] replay];     [replaySignal subscribeNext:^(id x) {         NSLog(@"小明看了%@", x);     }];     [replaySignal subscribeNext:^(id x) {         NSLog(@"小红也看了%@", x);     }];

 

 

 

 

 

 

Objective-C

 

1 2 3

2015-08-16 21:18:38.002 Test[1854:54712] 大导演拍了一部电影《我的男票是程序员》   2015-08-16 21:18:38.004 Test[1854:54712] 小明看了《我的男票是程序员》   2015-08-16 21:18:38.004 Test[1854:54712] 小红也看了《我的男票是程序员》

定时

每隔8个小时服一次药。

 

 

 

 

 

 

Objective-C

 

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[[RACSignal interval:60*60*8 onScheduler:[RACScheduler mainThreadScheduler]] subscribeNext:^(id x) {         NSLog(@"吃药");     }];

超时

等了你一个小时了，你还没来，我走了。

 

 

 

 

 

 

Objective-C

 

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[[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {             NSLog(@"我快到了");             [subscriber sendNext:nil];             [subscriber sendCompleted];             return nil;         }] delay:60*70] subscribeNext:^(id x) {             [subscriber sendNext:nil];             [subscriber sendCompleted];         }];         return nil;     }] timeout:60*60 onScheduler:[RACScheduler mainThreadScheduler]] subscribeError:^(NSError *error) {         NSLog(@"等了你一个小时了，你还没来，我走了");     }];

 

 

 

 

 

Objective-C

 

1 2	2015-08-16 21:40:09.068 Test[2041:64720] 我快到了   2015-08-16 22:40:10.048 Test[2041:64720] 等了你一个小时了，你还没来，我走了

重试

成功之前可能需要数百次失败。

 

 

 

 

 

 

Objective-C

 

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__block int failedCount = 0;     [[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         if (failedCount < 100) {             failedCount++;             NSLog(@"我失败了");             [subscriber sendError:nil];         }else{             NSLog(@"经历了数百次失败后");             [subscriber sendNext:nil];         }         return nil;     }] retry] subscribeNext:^(id x) {         NSLog(@"终于成功了");     }];

 

 

 

 

 

Objective-C

 

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2015-08-16 21:59:07.159 Test[2411:77080] 我失败了   2015-08-16 21:59:07.159 Test[2411:77080] 我失败了   2015-08-16 21:59:07.159 Test[2411:77080] 我失败了   2015-08-16 21:59:07.159 Test[2411:77080] 我失败了   2015-08-16 21:59:07.160 Test[2411:77080] 我失败了   2015-08-16 21:59:07.160 Test[2411:77080] 我失败了   2015-08-16 21:59:07.161 Test[2411:77080] 我失败了   2015-08-16 21:59:07.162 Test[2411:77080] 我失败了   ... 2015-08-16 21:59:07.162 Test[2411:77080] 我失败了   2015-08-16 21:59:07.163 Test[2411:77080] 我失败了   2015-08-16 21:59:07.163 Test[2411:77080] 我失败了   2015-08-16 21:59:07.163 Test[2411:77080] 我失败了   2015-08-16 21:59:07.164 Test[2411:77080] 我失败了   2015-08-16 21:59:07.164 Test[2411:77080] 我失败了   2015-08-16 21:59:07.164 Test[2411:77080] 我失败了   2015-08-16 21:59:07.165 Test[2411:77080] 经历了数百次失败后   2015-08-16 21:59:07.165 Test[2411:77080] 终于成功了

节流

不好意思，这里一秒钟只能通过一个人。

 

 

 

 

 

 

Objective-C

 

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[[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [subscriber sendNext:@"旅客A"];         dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{             [subscriber sendNext:@"旅客B"];         });         dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{             [subscriber sendNext:@"旅客C"];             [subscriber sendNext:@"旅客D"];             [subscriber sendNext:@"旅客E"];         });         dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{             [subscriber sendNext:@"旅客F"];         });         return nil;     }] throttle:1] subscribeNext:^(id x) {         NSLog(@"%@通过了",x);     }];

 

 

 

 

 

Objective-C

 

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2015-08-16 22:08:45.677 Test[2618:83764] 旅客A   2015-08-16 22:08:46.737 Test[2618:83764] 旅客B   2015-08-16 22:08:47.822 Test[2618:83764] 旅客E   2015-08-16 22:08:48.920 Test[2618:83764] 旅客F

条件

直到世界的尽头才能把我们

 

 

 

 

 

 

Objective-C

 

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[[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         [[RACSignal interval:1 onScheduler:[RACScheduler mainThreadScheduler]] subscribeNext:^(id x) {             [subscriber sendNext:@"直到世界的尽头才能把我们分开"];         }];         return nil;     }] takeUntil:[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {         dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{             NSLog(@"世界的尽头到了");             [subscriber sendNext:@"世界的尽头到了"];         });         return nil;     }]] subscribeNext:^(id x) {         NSLog(@"%@", x);     }];

 

 

 

 

 

Objective-C

 

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2015-08-16 22:17:22.648 Test[2766:88737] 直到世界的尽头才能把我们分开   2015-08-16 22:17:23.648 Test[2766:88737] 直到世界的尽头才能把我们分开   2015-08-16 22:17:24.645 Test[2766:88737] 直到世界的尽头才能把我们分开   2015-08-16 22:17:25.648 Test[2766:88737] 直到世界的尽头才能把我们分开   2015-08-16 22:17:26.644 Test[2766:88737] 直到世界的尽头才能把我们分开   2015-08-16 22:17:26.645 Test[2766:88737] 世界的尽头到了

完事

ReactiveCocoa是如此优雅，一旦使用，根本停不下来，上面也只是它的一角冰山，但愿我能挑起你的兴趣。

转载自：http://ios.jobbole.com/82356/