ReactiveCocoa RAC使用-处理多个网络请求

当需要在多个网络请求完成之后才进行更新UI或者类似的事情的时候，可以用rac_liftSelector

-(void)requestData
{
//网络请求1
    RACSignal *signal1 = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        NSLog(@"网络请求1");
        [subscriber sendNext:@"网络请求1"];
        return  nil;
    }];
    
//网络请求2
    RACSignal *signal2 = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        NSLog(@"网络请求2");
        [subscriber sendNext:@"网络请求2"];
        return  nil;
    }];

//网络请求3
    RACSignal *signal3 = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        NSLog(@"网络请求3");
        [subscriber sendNext:@"网络请求3"];
        return  nil;
    }];

       [self rac_liftSelector:@selector(dealDataWithData1:data2:data3) signal1,signal2,signal3, nil];

}

-(void)dealDataWithData1:(id)data1 data2:(id)data2 data3:(id)data3
{
//三个网络请求结束后在这里处理数据

}