ios - 在 react-native 的主线程上运行 swift 代码

Question

我正在尝试将 native react 应用程序转换到 chromecast。 chromecast GCKDeviceScanner 必须在主线程上运行。

React Native 页面说要在主线程上运行你必须这样做:

- (dispatch_queue_t)methodQueue
{
  return dispatch_get_main_queue();
}

我对swift和ios不是很熟悉，那么这段代码放在哪里，怎么用呢？我有我的方法:

let filterCriteria = GCKFilterCriteria(forAvailableApplicationWithID: "myApp")
    
    let deviceScanner = GCKDeviceScanner(filterCriteria: filterCriteria)
    if let deviceScanner = deviceScanner {
      deviceScanner.addListener(self)
      deviceScanner.startScan()
      deviceScanner.passiveScan = true
    }

关于如何在主线程上运行我的代码有什么想法吗？

Answer 1

要在主线程中运行该代码部分，您可以这样做:

DispatchQueue.main.async {
  let filterCriteria = GCKFilterCriteria(forAvailableApplicationWithID: "myApp")
  
  let deviceScanner = GCKDeviceScanner(filterCriteria: filterCriteria)
  if let deviceScanner = deviceScanner {
    deviceScanner.addListener(self)
    deviceScanner.startScan()
    deviceScanner.passiveScan = true
  }
}

另一个选项是 RunLoop.main.perform { .. }。

旧版本，在 Swift 4(甚至可能是 3？)之前:

dispatch_async(dispatch_get_main_queue()) {
  let filterCriteria = GCKFilterCriteria(forAvailableApplicationWithID: "myApp")
  
  let deviceScanner = GCKDeviceScanner(filterCriteria: filterCriteria)
  if let deviceScanner = deviceScanner {
    deviceScanner.addListener(self)
    deviceScanner.startScan()
    deviceScanner.passiveScan = true
  }
}