背景是我想在Mac上复制这种行为,并且Mountain Lion中没有任何等效的UIRefreshControl.

注意：这是iOS 6 – How can I get the “release to refresh” animation thing? like in mail?的延续

我在github上找到了2个项目：

https://github.com/ishkawa/ISRefreshControl

https://github.com/dbsGen/SlimeRefresh

然而,它正在起作用,以下对我来说是错误的：

1)我知道RXCocoa扩展中有一个rx_refreshing变量,但我无法让它在这个上下文中工作.

2)我绑定答案(这是一个变量的数组)两次.一旦我加载视图控制器,当UIRefreshControl刷新时再次加载.

3)我检查UIRefreshControl是否令人耳目一新的部分看起来很尴尬.感觉它是否违背了使用反应的目的？

...

let answers: Variable<[Answer]> = Variable([])

override func viewDidLoad() {       
  loadAnswers()
     .shareReplay(1)
     .bindTo(answers)
     .adddisposableto(self.disposeBag)
  setupRx()
}

func loadAnswers() -> Observable<[Answer]> {
  return Network.rxArrayRequest(Spark.Answers)
}  

func setupRx() {
  rc.rx_controlEvent(.ValueChanged)
    .map { _ in !self.rc.refreshing }
    .filter { $0 == false }
    .flatMapLatest { [uNowned self] _ in
      return self.loadAnswers()
    }
    .bindTo(answers)
    .adddisposableto(self.disposeBag)

  rc.rx_controlEvent(.ValueChanged)
    .map { _ in self.rc.refreshing }
    .filter { $0 == true }
    .subscribeNext { [uNowned self] _ in
      self.rc.endRefreshing()
    }
    .adddisposableto(self.disposeBag)
}

...

// `rc.rx_controlEvent(.ValueChanged)` only gets called once,// when the user pulls down.

rc.rx_controlEvent(.ValueChanged)       // user pulled down to refresh
  .map { _ in !self.rc.refreshing }     // !true -> false 
  .filter { $0 == false }               // false == false
  .flatMapLatest { [uNowned self] _ in
    return self.loadAnswers()           // request answers
  }
  .bindTo(answers)
  .adddisposableto(self.disposeBag)

rc.rx_controlEvent(.ValueChanged)       // user pulled down to refresh
  .map { _ in self.rc.refreshing }      // true -> true
  .filter { $0 == true }                // true == true
  .subscribeNext { [uNowned self] _ in
    self.rc.endRefreshing()             // end refreshing
  }
  .adddisposableto(self.disposeBag)

为了解决问题1,你是对的,你可以使用rx_refreshing来关闭刷新而不是endRefreshing().

为了解决问题2,我认为变量不是必需的或有用的,至少在这个例子中是这样.你仍然可以使用它.此外,没有必要在两个地方loadAnswers().

为了解决问题3,是的,你可以简化这一点并使用Rx多一点.

这里的代码实际上可以工作,使用rx_refreshing,并简化了很多事情：

let initial = Observable<Void>.just(())
let refresh = rc.rx_controlEvent(.ValueChanged).map { _ in () }
let answers = Observable.of(initial,refresh)
    .merge()
    .flatMapLatest{ _ in self.loadAnswers() }
    .shareReplayLatestWhileConnected()

answers
    .map { _ in false }
    .bindTo(rc.rx_refreshing)
    .adddisposableto(disposeBag)

// also use `answers` to bind to your data source,etc.

这是我使用的代码,所有UI的东西都很好地在主线程上完成：

if(refreshControl.refreshing) {
        dispatch_async(dispatch_get_global_queue(disPATCH_QUEUE_PRIORITY_DEFAULT,0),^{
            [self refreshItems];

            dispatch_async(dispatch_get_main_queue(),^{
                [refreshControl endRefreshing];
                [self.tableView reload];
                [self showUpdateInfo];                     
            });
        });
    }

知道是什么原因引起的吗？

编辑：这是我在代码中创建刷新控件的方法(在viewDidLoad中)：

UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
refreshControl.attributedTitle   = [[NSAttributedString alloc] initWithString: @"Checking for updates…"];
[refreshControl addTarget: self
                   action: @selector(refreshOutdatedItems)
         forControlEvents: UIControlEventValueChanged];

self.refreshControl = refreshControl;

- (void)refreshOutdatedItems
{
    NSLog(@"refresh");

    if (self.refreshControl.refreshing) {
        dispatch_async(dispatch_get_global_queue(disPATCH_QUEUE_PRIORITY_DEFAULT,^{
            for (double i = 0 ; i < 100000000; i++){

            };

            dispatch_async(dispatch_get_main_queue(),^{

                [self.refreshControl endRefreshing];
                [self performSelector:@selector(showUpdateInfo) withObject:nil afterDelay:0.5];

            });
        });
    }
}

如果有帮助,请告诉我.