ReactiveCocoa框架（程序定位）

使用RAC方式与传统方式做定位功能的对比

首先，因为使用定位功能，所以要在info.plist文件里面做请求描述设置

添加下面两个字段：
Privacy - Location Always Usage Description
Privacy - Location When In Use Usage Description

然后是代码部分：

.h文件
`#import "ViewController.h"

@import ReactiveCocoa;

@interface ViewController ()

@property (nonatomic,strong)CLLocationManager * manager;//位置管理器
@property (nonatomic) CLGeocoder * geocoder;//返地理位置编码
@property (weak, nonatomic) IBOutlet UILabel *placeLabel;

@end

@implementation ViewController

-(CLLocationManager * )manager{

if (!_manager) {

    _manager = [[CLLocationManager alloc]init];
    _manager.delegate = self;
}
return _manager;

}

-(CLGeocoder *)geocoder{

if (!_geocoder) {

    _geocoder = [[CLGeocoder alloc]init];
}
return _geocoder;

}

-(RACSignal *)authorizedSignal{

if ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusNotDetermined) {

    [self.manager requestAlwaysAuthorization];

    return [[self rac_signalForSelector:@selector(locationManager:didChangeAuthorizationStatus:) fromProtocol:@protocol(CLLocationManagerDelegate)] map:^id(id value) {

        return @([value[1] integerValue] == kCLAuthorizationStatusAuthorizedAlways);

    }];
}
return [RACSignal return:@([CLLocationManager authorizationStatus]== kCLAuthorizationStatusAuthorizedAlways)];

}

• (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view, typically from a nib.
  // RACSequence * s1 = [[[@[@(1),@(2),@(3)] rac_sequence] map:^id(id value) {
  //
  // return @([value integerValue]+2);
  // }] filter:^BOOL(id value) {
  //
  // return [value integerValue] <5;
  // }];
  //
  // NSLog(@"%@",[s1 array]);
  // //3,4

  // RACSequence * s1 = [@[@(1),@(2),@(3)] rac_sequence];
  // RACSequence * s2 = [@[@(1),@(3),@(9)] rac_sequence];
  //
  // RACSequence s3 =[[@[s1,s2] rac_sequence] flattenMap:^RACStream (id value) {
  //
  // return [value filter:^BOOL(id value) {
  //
  // return [value integerValue] % 3 ==0;
  // }];
  // }];
  // NSLog(@"%@",[s3 array]);
  // //3,3,9

  //知识点：获取某个对象的属性时，生成信号量
  //传统OC 使用KVO技术

  // RAC RACObserve观察者(对象，属性)
  // RACSignal * signal = RACObserve(self, title);
  //
  // [signal subscribeNext:^(id x) {
  //
  //
  // }];

  // 常见的使用方式,进行绑定，将我们一个已知的属性绑定到另外一个对象的属性上
  // RAC() = RACObserve(<#TARGET#>, <#KEYPATH#>)

  [[[[[self authorizedSignal] filter:^BOOL(id value) {

  return [value boolValue];

  }] flattenMap:^RACStream *(id value){

  return [[[[[[self rac_signalForSelector:@selector(locationManager:didUpdateLocations:) fromProtocol:@protocol(CLLocationManagerDelegate)] map:^id(id value) {
  
      return value[1];
  }] merge:[[self rac_signalForSelector:@selector(locationManager:didFailWithError:) fromProtocol:@protocol(CLLocationManagerDelegate)]map:^id(id value) {
  
      return [RACSignal error:value[1]];
  }]] take:1] initially:^{
  
      [self.manager startUpdatingLocation];
  }] finally:^{
  
      [self.manager stopUpdatingLocation];
  }];

  }] flattenMap:^RACStream *(id value) {

  CLLocation * location =[value firstObject];
  return [RACSignal createSignal:^RACDisposable *(id subscriber) {
  
      [self.geocoder reverseGeocodeLocation:location completionHandler:^(NSArray * _Nullable placemarks, NSError * _Nullable error) {
  
          if (error) {
  
              [subscriber sendError:error];
          }else{
  
              [subscriber sendNext:[placemarks firstObject]];
              [subscriber sendCompleted];
          }
      }];
      return [RACDisposable disposableWithBlock:^{
  

        }];
    }];
}] subscribeNext:^(id x) {

    NSLog(@"%@",x);
    self.placeLabel.text =[x addressDictionary][@"Name"];
    NSLog(@"地址%@",self.placeLabel.text);
}];

}`