RACSignal使用基础

获得一个信号：

单元信号

RACSignal *signal1 = [RACSignal return:@"Some value"];
RACSignal *signal2 = [RACSignal error:[NSError new]];
RACSignal *signal3 = [RACSignal empty];
RACSignal *signal4 = [RACSignal never];

动态信号

RACSignal *signal5 = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
    [subscriber sendNext:@1];
    [subscriber sendNext:@2];
    [subscriber sendError:[NSError new]];
    [subscriber sendCompleted];
    return [RACDisposable disposableWithBlock:^{
    NSLog(@"信号结束");
  }];
}];

Cocoa桥接:

// 给View的方法添加一个信号，当这个信号被订阅，同时执行了它的这个方法时，就会给订阅者发送内容。
UIView *view = [UIView new];
view.backgroundColor = [UIColor redColor];
RACSignal *signal6 = [view rac_signalForSelector:@selector(setFrame:)];
[signal6 subscribeNext:^(id x) {
     NSLog(@"next value is %@",x);
}];
[view setFrame:CGRectMake(0, 0, 375, 264)];
RACSignal *signal7 = [[UIButton new] rac_signalForControlEvents:UIControlEventTouchUpInside];
RACSignal *signal8 = [[UIView new] rac_willDeallocSignal];
RACSignal *signal9 = RACObserve([UIView new], backgroundColor);

信号变化:

RACSignal *signal10 = [signal1 map:^id(NSString *value) {
     return  [value substringToIndex:1];
}];

序列转换:

 RACSequence *sequence1 = [RACSequence return:@1];
 RACSignal *signal11 = sequence1.signal;

订阅方法:

 [[signal11 subscribeNext:^(id x) {
        NSLog(@"next value is %@",x);
 } error:^(NSError *error) {
    NSLog(@"error:%@",error);
 } completed:^{
        NSLog(@"completed");
 }] dispose];

Cocoa桥接:

RACSignal *sg1 = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
        [subscriber sendNext:@"网络请求数据1"];
        return nil;
    }];
       
RACSignal *sg2 = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
        [subscriber sendNext:@"网络请求数据2"];
        return nil;
    }];
       
RACSignal *sg3 = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
        [subscriber sendNext:@"网络请求数据3"];
        return nil;
    }];
    
// Cocoa桥接
// 当全部信号执行完毕之后，最后刷新UI的问题
// rac_liftSelector
// 类似于dispatch_group 中的组
// 多线程中的组 等所有的请求都完毕之后 去更新UI
// 信号跟参数的个数要一一对应
[self rac_liftSelector:@selector(updateUI:str:str:) withSignals:sg1, sg2, sg3, nil];
[self rac_liftSelector:@selector(updateUI:str:str:) withSignalsFromArray:@[sg1, sg2, sg3]];


- (void)updateUI:(id)str1 str:(id)str2 str:(id)str3 {
    // 回传过来
    NSLog(@"%@-%@-%@",str1,str2,str3);
}

订阅过程:

 RACSignal *signal = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
   [subscriber sendNext:@1];
   [subscriber sendNext:@2];
   [subscriber sendCompleted];
   return [RACDisposable disposableWithBlock:^{
        NSLog(@"dispose");
   }];
 }];

 RACDisposable *disposable = [signal subscribeNext:^(id x) {
   NSLog(@"next%@",x);
 } error:^(NSError *error) {
   NSLog(@"error:%@",error);
 } completed:^{
   NSLog(@"completed");
 }];
[disposable dispose];