呈现viewcontroller

Question

我正在尝试使用以下堆栈跟踪来呈现ViewController但崩溃了。 有人可以检查和帮助。

presentViewController的代码

func moveToChatView(){
 SwiftSpinner.show(Strings.loading)

  let destViewController:GroupChatViewController  = UIStoryboard(name:      "GroupChat", bundle:  nil).instantiateViewControllerWithIdentifier("GroupChatViewController") as!    GroupChatViewController
 destViewController.currentRiderRideID = self.riderRideId!
if NSThread.isMainThread() == true{
self.presentViewController(destViewController, animated: true, completion:   nil)
 }else{
    dispatch_sync(dispatch_get_main_queue()){
  self.presentViewController(destViewController, animated: true, completion:   nil)
   }
 }
}

致命异常：NSRangeException 0 CoreFoundation 0x182b482d8 exceptionPreprocess 1 libobjc.A.dylib 0x1948140e4 objc_exception_throw 2 CoreFoundation 0x182a2f4c0 CFStringConvertNSStringEncodingToEncoding 3 UIKit 0x1879e01b4 - [UINib instantiateWithOwner：options：] 4 UIKit 0x1878dc318 - [UIViewController _loadViewFromNibNamed：bundle：] 5 UIKit 0x1875c09bc - [UIViewController loadViewIfRequired] 6 UIKit 0x1875c0928 - [UIViewController视图] 7 UIKit 0x187cb618c - [_ UIFullscreenPresentationController _setPresentedViewController：] 8 UIKit 0x1878c60dc - [UIPresentationController initWithPresentedViewController：presentsViewController：] 9 UIKit 0x1878e2378 - [UIViewController _presentViewController：withAnimationController：completion：] 10 UIKit 0x1878e48c8 __62- [UIViewController presentViewController：animated：completion：] _ block_invoke 11 UIKit 0x1876ae0ec - [UIViewController presentViewController：animated：completion：] 12 Quickride 0x100451968部分适用于LiveRideMapViewController。（moveToChatView（） - ＆gt;（））。（闭包＃1）（LiveRideMapViewController.swift：1868） 13 libdispatch.dylib 0x194e91954 _dispatch_client_callout 14 libdispatch.dylib 0x194e9f590 _dispatch_barrier_sync_f_slow_invoke 15 libdispatch.dylib 0x194e91954 _dispatch_client_callout 16 libdispatch.dylib 0x194e9620c _dispatch_main_queue_callback_4CF 17 CoreFoundation 0x182aff7f8 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE 18 CoreFoundation 0x182afd8a0 __CFRunLoopRun 19 CoreFoundation 0x182a292d4 CFRunLoopRunSpecific 20 GraphicsServices 0x18c47f6fc GSEventRunModal 21 UIKit 0x187626f40 UIApplicationMain 22 Quickride 0x100259a70 main（AppDelegate.swift：23） 23 libdyld.dylib 0x194ebea08 start

Answer 1

通常不使用dispatch_ 同步，而是使用dispatch_ async ，而不必检查主线程是否在线程，如果它是一个UI操作，并且它有可能在一个反向线程上，只需将dispatch_ async 发送到主队列，该主队列将在主队列的下一个运行循环上执行UI操作，用户界面将是“顺畅的”。试试这个：

func moveToChatView(){
    SwiftSpinner.show(Strings.loading)

    let destViewController:GroupChatViewController  = UIStoryboard(name:"GroupChat", bundle:  nil).instantiateViewControllerWithIdentifier("GroupChatViewController") as!    GroupChatViewController
    destViewController.currentRiderRideID = self.riderRideId!
    dispatch_async(dispatch_get_main_queue()){
       self.presentViewController(destViewController, animated: true,completion:nil)
   }
}