转载 http://www.open-open.com/lib/view/open1440060663129.html
前戏
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。
@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。
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。
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";
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。
@protocol Programmer <NSObject> - (void)makeAnApp; @end
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];
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。
[[[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"}];
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。
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); }];
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。
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%@",246)">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。
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); }];
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。
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,246)">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。
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(@"%@",246)">2015-08-16 20:00:12.853 Test[740:15871] 金
归约
糖加水变成糖水。
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(@"%@",246)">2015-08-16 20:07:00.356 Test[807:19177] 糖水
过滤
未满十八岁,禁止进入。
[[[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(@"%@",246)">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。
[[[[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(@"%@",246)">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。
[[[[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"); }];
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。
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];
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。
[[[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"); }];
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。
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%@",246)">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。
[[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。
[[[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"); }];
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。
__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"); }];
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。
[[[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)),^{ [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)),^{ [subscriber sendNext:@"旅客F"]; }); return nil; }] throttle:1] subscribeNext:^(id x) { NSLog(@"%@通过了",246)">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分开。
[[[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)),^{ NSLog(@"世界的尽头到了"); [subscriber sendNext:@"世界的尽头到了"]; }); return nil; }]] subscribeNext:^(id x) { NSLog(@"%@",246)">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。
来自:@L_404_0@