詳解如何使用ReactiveObjC

更新時間：2021年06月07日 11:34:46 作者：為童沉淪

RAC 指的就是 RactiveCocoa ，是 Github 的一個開源框架，能夠通過信號提供大量方便的事件處理方案，讓我們更簡單粗暴地去處理事件，現(xiàn)在分為 ReactiveObjC（OC）和 ReactiveSwift（swift）。本文將詳細(xì)介紹如何使用ReactiveObjC。

概述

RAC架構(gòu)框架圖

信號流程

基本使用

1、基本控件

UITextField

//監(jiān)聽文本輸入
 [[_textField rac_textSignal] subscribeNext:^(NSString * _Nullable x) {
        NSLog(@"%@",x);
 }];
  
 
//可根據(jù)自己想要監(jiān)聽的事件選擇
 [[_textField rac_signalForControlEvents:UIControlEventEditingChanged] subscribeNext:^(__kindof UIControl * _Nullable x) {
     NSLog(@"%@",x);
 }];
//添加條件 -- 下面表示輸入文字長度 > 10 時才會調(diào)用subscribeNext
 [[_textField.rac_textSignal filter:^BOOL(NSString * _Nullable value) {
     return value.length > 10;
 }] subscribeNext:^(NSString * _Nullable x) {
     NSLog(@"輸入框內(nèi)容：%@", x); }];

UIButton

//監(jiān)聽按鈕點(diǎn)擊事件
[[_btn rac_signalForControlEvents:UIControlEventTouchUpInside] subscribeNext:^(__kindof UIControl * _Nullable x) {
        NSLog(@"-->%@",x);
}];

計時器（interval、delay）

//類似timer
@weakify(self)
self.disposable = [[RACSignal interval:2 onScheduler:[RACScheduler mainThreadScheduler]] subscribeNext:^(NSDate * _Nullable x) {
        @strongify(self)
        NSLog(@"時間：%@", x); // x 是當(dāng)前的時間
        //關(guān)閉計時器
        [self.disposable dispose];
}];
//延時
[[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        [subscriber sendNext:@"延時2秒"];
        return nil;<br>}] delay:2] subscribeNext:^(id x) {
         
        NSLog(@"-->%@",x);
}];

2、監(jiān)聽屬性變化

//監(jiān)聽self的name屬性
[RACObserve(self, name) subscribeNext:^(id  _Nullable x) {
        NSLog(@"屬性的改變-->%@",x);
}];
[[self rac_valuesForKeyPath:@"name" observer:self] subscribeNext:^(id  _Nullable x) {
        NSLog(@"屬性的改變-->%@", x);
}];
//此處RAC宏相當(dāng)于讓_label訂閱了_textField的文本變化信號
//賦值給label的text屬性
RAC(_label, text) = _textField.rac_textSignal;

3、遍歷數(shù)組和字典

//遍歷數(shù)組
 NSArray *array = @[@"1", @"2", @"3", @"4", @"5"];
[array.rac_sequence.signal subscribeNext:^(id  _Nullable x) {
      NSLog(@"內(nèi)容-->%@", x)<br>}];

4、監(jiān)聽 Notification 通知事件

[[[NSNotificationCenter defaultCenter] rac_addObserverForName:@"notification" object:nil] subscribeNext:^(NSNotification * _Nullable x) {
        NSLog(@"-->%@", x);
}];

5、代替Delegate代理

//監(jiān)聽按鈕點(diǎn)擊方法的信號
//當(dāng)執(zhí)行完btnClickAction后會執(zhí)行此訂閱
[[self rac_signalForSelector:@selector(btnClickAction:)] subscribeNext:^(RACTuple * _Nullable x) {
        NSLog(@"-->%@", x);
}];
-(void) btnClickAction:(UIButton *)btn
{
    NSLog(@"按鈕點(diǎn)擊");
}

二、RAC常用類

RACSignal

RACSignal *signal = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
      [subscriber sendNext:@"🍺🍺🍺🍺🍺🍺🍺"];
      [subscriber sendCompleted];
      return [RACDisposable disposableWithBlock:^{
          NSLog(@"銷毀了🍺🍺🍺");
      }];
  }];
  [signal subscribeNext:^(id  _Nullable x) {
      NSLog(@"%@",x);
  }];

RACSubject(可發(fā)送信號也可以訂閱信號)

RACTuple（元組）-- 其內(nèi)部就是封裝了數(shù)組，用起來跟數(shù)組差不多

//通過定值創(chuàng)建RACTuple
RACTuple *tuple = [RACTuple tupleWithObjects:@"1", @"2", @"3", nil];
//利用 RAC 宏快速封裝
RACTuple *tuple2 = RACTuplePack(@"1", @"2", @"3");
//從別的數(shù)組中獲取內(nèi)容
RACTuple *tuple3 = [RACTuple tupleWithObjectsFromArray:@[@"1", @"2", @"3"]];
 
NSLog(@"元組-->%@", tuple3[0]);
NSLog(@"第一個元素-->%@", [tuple3 first]);
NSLog(@"最后一個元素-->%@", [tuple3 last]);

RACMulticastConnection -- 用于當(dāng)一個信號，被多次訂閱時，為了保證創(chuàng)建信號時，避免多次調(diào)用創(chuàng)建信號中的block

RACSignal *signal1 = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
       [subscriber sendNext:@"signal1-->🍺🍺🍺🍺🍺🍺🍺"];
       [subscriber sendCompleted];
       return [RACDisposable disposableWithBlock:^{
           NSLog(@"signal1銷毀了");
       }];
   }];
    
   RACMulticastConnection *connection = [signal1 publish];
    
   [connection.signal subscribeNext:^(id  _Nullable x) {
       NSLog(@"subscribeNext-->1");
   }];
   [connection.signal subscribeNext:^(id  _Nullable x) {
       NSLog(@"subscribeNext-->2");
   }];
   [connection.signal subscribeNext:^(id  _Nullable x) {
       NSLog(@"subscribeNext-->3");
   }];
   [connection connect];

RACCommand -- 可以監(jiān)聽信號的狀態(tài)等

NSString *input = @"執(zhí)行";
RACCommand *command = [[RACCommand alloc] initWithSignalBlock:^RACSignal * _Nonnull(id  _Nullable input) {
    NSLog(@"input-->%@",input);
    return [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
        [subscriber sendNext:@"🍺🍺🍺🍺🍺🍺🍺"];
        [subscriber sendError:[NSError errorWithDomain:@"error" code:-1 userInfo:nil]];
//            [subscriber sendCompleted];
        return [RACDisposable disposableWithBlock:^{
            NSLog(@"signal銷毀了");
        }];
    }];
}];
[command.executionSignals subscribeNext:^(RACSignal   * _Nullable x) {
    NSLog(@"executionSignals-->%@",x);
    [x subscribeNext:^(id  _Nullable x) {
        NSLog(@"executionSignals-->subscribeNext-->%@",x);
    }];
}];
[[command.executionSignals switchToLatest] subscribeNext:^(id  _Nullable x) {
    NSLog(@"switchToLatest-->%@",x);
}];
[command.executing subscribeNext:^(id  _Nullable x) {
    NSLog(@"executing-->%@",x);
}];
[command.errors subscribeNext:^(id  _Nullable x) {
    NSLog(@"errors-->%@",x);
}];
//開始執(zhí)行
[command execute:input];

三、高級函數(shù)使用

1、連接信號、合并信號等

首先創(chuàng)建兩個信號signal1和signal2來演示

RACSignal *signal1 = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
     [subscriber sendNext:@"signal1-->🍺🍺🍺🍺🍺🍺🍺"];
     [subscriber sendCompleted];
     return [RACDisposable disposableWithBlock:^{
         NSLog(@"signal1銷毀了");
     }];
 }];
 RACSignal *signal2 = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
     [subscriber sendNext:@"signal2-->🍺🍺🍺🍺🍺🍺🍺"];
     [subscriber sendCompleted];
     return [RACDisposable disposableWithBlock:^{
         NSLog(@"signal2銷毀了");
     }];
 }];

1.1、 concat -- 當(dāng)多個信號發(fā)出的時候，有順序的接收信號

一個信號signal3去監(jiān)聽signal1和signal2，必須是接收signal1完后才會接收signal2

RACSignal *signal3 = [signal1 concat:signal2];
  [signal3 subscribeNext:^(id  _Nullable x) {
      NSLog(@"signal3-->%@",x);
  }];

1.2、 combineLatestWith -- 將多個信號合并起來，并且拿到各個信號的最新的值,必須每個合并的signal至少都有過一次sendNext，才會觸發(fā)合并的信號(訂閱者每次接收的參數(shù)都是所有信號的最新值),不論觸發(fā)哪個信號都會觸發(fā)合并的信號

一個信號signal3去監(jiān)聽signal1和signal2，每次回調(diào)兩個信號的最新值

RACSignal *signal3 = [signal1 combineLatestWith:signal2];
   [signal3 subscribeNext:^(id  _Nullable x) {
       NSLog(@"%@",x);
   }];

PS：注釋signal1的sendNext方法，直接銷毀了，所以每個singal必須有sendNext方法

1.3、 then -- 用于連接兩個信號，等待第一個信號完成，才會連接then返回的信號

RACSignal *signal3 = [signal1 then:^RACSignal * _Nonnull{
    return signal2;
}];
[signal3 subscribeNext:^(id  _Nullable x) {
    NSLog(@"signal3-->%@",x);
}];

1.4、 merge -- 把多個信號合并為一個信號來監(jiān)聽，任何一個信號有新值的時候就會調(diào)用

一個信號signal3去監(jiān)聽signal1和signal2，每次回調(diào)一個信號

RACSignal *signal3 = [signal1 merge:signal2];
[signal3 subscribeNext:^(id  _Nullable x) {
    NSLog(@"signal3-->%@",x);
}];

1.5、 zipWith -- 把兩個信號壓縮成一個信號，只有當(dāng)兩個信號都發(fā)出信號內(nèi)容時，才會觸發(fā)

一個信號signal3去監(jiān)聽signal1和signal2，但必須兩個信號都有發(fā)出（不需要同時，例如signal1信號發(fā)出了，signal2信號等了10秒之后發(fā)出，那么signal3的訂閱回調(diào)是等signal2信號發(fā)出的那一刻觸發(fā)）

RACSignal *signal3 = [signal1 zipWith:signal2];
[signal3 subscribeNext:^(id  _Nullable x) {
    NSLog(@"signal3-->%@",x);
}];

1.6、 reduce 聚合 -- 把多個信號的值按照自定義的組合返回

RACSignal *signal3 = [RACSignal combineLatest:@[signal1,signal2] reduce:^id(NSString *s1 ,NSString *s2){
    return [NSString stringWithFormat:@"%@ %@",s1,s2];
}];
[signal3 subscribeNext:^(id x) {
    NSLog(@"%@",x);
}];

2、flattenMap & map 映射

flattenMap 的底層實現(xiàn)是通過bind實現(xiàn)的

map 的底層實現(xiàn)是通過 flattenMap 實現(xiàn)的

//map事例
[[_textField.rac_textSignal map:^id _Nullable(NSString * _Nullable value) {
        return [NSString stringWithFormat:@"%@🍺🍺🍺🍺🍺🍺🍺",value];
    }] subscribeNext:^(id  _Nullable x) {
        NSLog(@"-->%@",x);
    }] ;
//flattenMap事例
 [[_textField.rac_textSignal flattenMap:^__kindof RACSignal * _Nullable(NSString * _Nullable value) {
        return [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
            [subscriber sendNext:[NSString stringWithFormat:@"%@🍺🍺🍺🍺🍺🍺🍺",value]];
            [subscriber sendCompleted];
            return [RACDisposable disposableWithBlock:^(){}];
        }];
    }] subscribeNext:^(id  _Nullable x) {
        NSLog(@"-->%@",x);
    }] ;

3、filter -- 過濾、ignore -- 忽略、distinctUntilChanged -- 忽略相同

filter、ignore

//map事例
[[_textField.rac_textSignal map:^id _Nullable(NSString * _Nullable value) {
        return [NSString stringWithFormat:@"%@🍺🍺🍺🍺🍺🍺🍺",value];
    }] subscribeNext:^(id  _Nullable x) {
        NSLog(@"-->%@",x);
    }] ;
//flattenMap事例
 [[_textField.rac_textSignal flattenMap:^__kindof RACSignal * _Nullable(NSString * _Nullable value) {
        return [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
            [subscriber sendNext:[NSString stringWithFormat:@"%@🍺🍺🍺🍺🍺🍺🍺",value]];
            [subscriber sendCompleted];
            return [RACDisposable disposableWithBlock:^(){}];
        }];
    }] subscribeNext:^(id  _Nullable x) {
        NSLog(@"-->%@",x);
    }] ;

distinctUntilChanged

RACSubject *subject = [RACSubject subject];
   [[subject distinctUntilChanged] subscribeNext:^(id  _Nullable x) {
       NSLog(@"-->%@",x);
   }];
   [subject sendNext:@"123"];
   [subject sendNext:@"123"];
   [subject sendNext:@"123"];
   [subject sendNext:@"🍺🍺🍺🍺🍺🍺"];
   [subject sendNext:@"🍺🍺🍺🍺🍺🍺"];
   [subject sendCompleted];