iOS 开发之 ReactiveCocoa(进阶)

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Map : 映射

 

UITextField *textField =[[UITextField alloc]initWithFrame:CGRectMake(100, 100, 100, 40)];

textField.backgroundColor =[UIColor redColor];

[self.view addSubview:textField];

 

[[textField.rac_textSignal map:^id(NSString * value) {

 

        return @(value.length);

 

  }] subscribeNext:^(NSNumber * x) {

 

        NSLog(@"%@",x);

   }];

 

输入Ricky:

 

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结果:

 

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filter: 过滤

 

//只有当text.length>3的时候才会订阅改消息

    [[textField.rac_textSignal filter:^BOOL(NSString * text) {

 

        return text.length>3;

 

    }] subscribeNext:^(id x) {

 

        NSLog(@"%@",x);

 

    }];

 

同样输入Ricky结果就是:

 

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delay:延时

 

//延时2秒发送消息

 

       RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {

 

            [subscriber sendNext:@"Ricky"];

            [subscriber sendCompleted];

 

            return nil;

 

        }] delay:2];

 

 

        [signal subscribeNext:^(id x) {

 

            NSLog(@"%@",x);

        }];

 

startWith:在发送消息之前,先发送一个消息

 

RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {

 

            [subscriber sendNext:@"Ricky"];

            [subscriber sendCompleted];

 

            return nil;

 

        }] startWith:@"RAC"];

 

 

        [signal subscribeNext:^(id x) {

 

            NSLog(@"%@",x);

        }];

 

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timeout :超时

 

//设置超时时间为2秒,当超过2秒还没有发送消息的时候,就不会发送了

        RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {

 

            [[RACScheduler mainThreadScheduler] afterDelay:3 schedule:^{

 

                [subscriber sendNext:@"Ricky"];

                [subscriber sendCompleted];

            }];

 

            return nil;

 

        }] timeout:2 onScheduler:[RACScheduler mainThreadScheduler]];

 

 

        [signal subscribeNext:^(id x) {

 

            NSLog(@"%@",x);

        }];

 

take :发送多个消息的时候,取最前面的几条

 

RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {

 

                [subscriber sendNext:@"Ricky1"];

                [subscriber sendNext:@"Ricky2"];

                [subscriber sendNext:@"Ricky3"];

                [subscriber sendNext:@"Ricky4"];

                [subscriber sendCompleted];

 

                return nil;

 

            }] take:2];

 

 

            [signal subscribeNext:^(id x) {

 

                NSLog(@"%@",x);

            }];

 

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takelast :发送多个消息的时候,取最后面的几条

 

RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {

 

                [subscriber sendNext:@"Ricky1"];

                [subscriber sendNext:@"Ricky2"];

                [subscriber sendNext:@"Ricky3"];

                [subscriber sendNext:@"Ricky4"];

                [subscriber sendCompleted];

 

                return nil;

 

            }] takeLast:3];

 

 

            [signal subscribeNext:^(id x) {

 

                NSLog(@"%@",x);

            }];

 

takeUntil: RACSignal (发送在takeUntil后面的信号完成前的消息)

 

// RAC这个消息是2秒后完成,所以Ricky1 Ricky2这两个消息是可以发送到 而3秒后的Ricky3 Ricky4就不会发送.

            RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {

 

                [subscriber sendNext:@"Ricky1"];

                [subscriber sendNext:@"Ricky2"];

 

                dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

 

                    [subscriber sendNext:@"Ricky3"];

                    [subscriber sendNext:@"Ricky4"];

                     [subscriber sendCompleted];

                });

 

                [subscriber sendCompleted];

 

                return nil;

 

            }] takeUntil:[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {

 

                dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

 

                    [subscriber sendNext:@"RAC"];

                    [subscriber sendCompleted];

                });

 

 

                return nil;

 

            }]];

 

 

            [signal subscribeNext:^(id x) {

 

                NSLog(@"%@",x);

            }];

 

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takeWhileBlock :当takeWhileBlock返回YES的时候发送消息

 

RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {

 

                [subscriber sendNext:@"Ricky1"];

                [subscriber sendNext:@"Ricky2"];

                [subscriber sendNext:@"Ricky3"];

                [subscriber sendNext:@"Ricky4"];

                [subscriber sendCompleted];

 

 

                return nil;

 

            }] takeWhileBlock:^BOOL(id x) {

 

                return YES;

 

            }];

 

            [signal subscribeNext:^(id x) {

 

                NSLog(@"%@",x);

            }];

 

skip: 跳过

 

//跳过前2次

    RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {

 

        [subscriber sendNext:@"Ricky1"];

        [subscriber sendNext:@"Ricky2"];

        [subscriber sendNext:@"Ricky3"];

        [subscriber sendNext:@"Ricky4"];

        [subscriber sendCompleted];

 

        return nil;

 

    }] skip:2];

 

 

    [signal subscribeNext:^(id x) {

 

        NSLog(@"%@",x);

    }];

 

skipWhileBlcok 和 skipUntilBlcok

 

  • skipWhileBlcok:当Block返回YES的时候跳过,返回No的时候发送.

  • skipUntilBlcok: skipUntilBlcok和skipWhileBlcok相反,当Block返回NO的时候跳

  • 过,返回YES的时候发送.

 

结合及时搜索优化

 

当我们在做及时搜索的时候,例如在UITextField中输入搜索内容,每当我们输入一个字符的时候当会请求服务器,无形中给服务器带来了很大的压力

 

UITextField *textField =[[UITextField alloc]initWithFrame:CGRectMake(100, 100, 100, 40)];

    textField.backgroundColor =[UIColor redColor];

 

    [self.view addSubview:textField];

 

 

    [textField.rac_textSignal subscribeNext:^(NSString * text) {

 

        NSLog(@"request--- %@",text);

    }];

 

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  • 优化请求时间间隔:throttle(节流)

 

throttle:设置一个间隔时间,当两次信号之间的时间差下于这个时间就不会发送请求

 

[[textField.rac_textSignal throttle:0.3] subscribeNext:^(NSString * text) {

 

        NSLog(@"request--- %@",text);

    }];

 

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  • distinctUntilChanged: 优化请求字符一样的时候(当后一个请求和前一个请求一样的时候,就可以不用请求)

 

  [[[textField.rac_textSignal throttle:0.3]distinctUntilChanged]

 

     subscribeNext:^(NSString * text) {

 

        NSLog(@"request--- %@",text);

    }];

 

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  • ignore :忽略某些 例如上面的空字符

 

[[[[textField.rac_textSignal throttle:0.3]distinctUntilChanged] ignore:@"" ]

 

     subscribeNext:^(NSString * text) {

 

        NSLog(@"request--- %@",text);

    }];

 

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  • switchToLatest :当你请求数据的时候,网络会有延迟,数据还没有返回回来,这时候你发送了新的请求,则我们取消前一次的请求,只发送最新的请求.

 

[[[[[[textField.rac_textSignal throttle:0.3]distinctUntilChanged] ignore:@"" ] map:^id(id value) {

 

        return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {

 

            [subscriber sendNext:@"Request --- ricky"];

 

            return nil;

        }];

 

    }] switchToLatest]

 

     subscribeNext:^(NSString * text) {

 

        NSLog(@"request--- %@",text);

    }];

 

多个信号处理

 

RACSignal *singalA = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {

 

        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

 

 

            [subscriber sendNext:@"singalA"];

            [subscriber sendCompleted];

        });

 

        return nil;

    }];

 

 

    RACSignal *singalB = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {

 

 

        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

 

 

            [subscriber sendNext:@"singalB"];

            [subscriber sendCompleted];

        });

 

        return nil;

    }];

 

merge: 同时订阅2个信号

 

   [[singalA merge:singalB] subscribeNext:^(id x) {

 

        NSLog(@"%@",x);

    }];

 

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singalA延迟2秒,singalB延迟5秒,她们相差了3秒.说明他们是同时发送的

 

concat

 

singalA完成后 才会订阅singalB 有点像串行队列 A失败了 B就不会被订阅

 

    [[singalA concat:singalB] subscribeNext:^(id x) {

 

        NSLog(@"%@",x);

    }];

 

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singalA延迟2秒,singalB延迟5秒,她们相差了5秒.说明A发送完,B才发送的.

 

zipWith和combineLatest:每个信号都至少要发送一次才可以被订阅.

 

[[singalA zipWith:singalB] subscribeNext:^(RACTuple * tuple) {

 

        NSLog(@"%@",tuple);

    }];

 

     [[RACSignal combineLatest:@[singalA,singalB]] subscribeNext:^(RACTuple * tuple) {

 

        NSLog(@"%@",tuple);

 

    }];

 

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RAC中的宏(结合例子)

 

  • UIButton中没有setbackgroundColor forstatus这个方法,使用RAC很简单实现

 

UIButton *button =[UIButton buttonWithType:UIButtonTypeCustom];

 

    button.frame = CGRectMake(100, 100, 100, 100);

    button.backgroundColor = [UIColor yellowColor];

 

    [self.view addSubview:button];

 

 

    RAC(button,backgroundColor) = [RACObserve(button, selected) map:^id(NSNumber * selected) {

 

        return [selected boolValue]?[UIColor yellowColor]:[UIColor redColor];

    }];

 

    [[button rac_signalForControlEvents:UIControlEventTouchUpInside] subscribeNext:^(UIButton * x) {

 

 

        x.selected = !x.selected;

 

    }];

 

  • RAC快速实现秒表

 

UILabel *lab =[[UILabel alloc]initWithFrame:CGRectMake(100, 100, 200, 50)];

    lab.backgroundColor =[UIColor cyanColor];

 

    [self.view addSubview:lab];

 

 

    RAC(lab,text) = [[RACSignal interval:1 onScheduler:[RACScheduler mainThreadScheduler]] map:^id(NSData * value) {

 

        return value.description;

    }];

 

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