Swift - performSegueWithIdentifier in thread - swift

Question

i've got this type of problem :
With my app i'm able to connect my iPhone with a BLE device so when i connect their together i'm transported into an another view.
Into this view i've to check always if i'm connected yet in a thread func.
If my connection is lost i've to call the performSegueWithIdentifier method.
But... When i do it, xCode give me back a bad report that says :
This application is modifying the autolayout engine from a background
thread, which can lead to engine corruption and weird crashes. This
will cause an exception in a future release.
This is my short code :
override func viewDidLoad(){
super.ViewDidLoad()
let priority = DISPATCH_QUEUE_PRIORITY_DEFAULT
dispatch_async(dispatch_get_global_queue(priority, 0)) {
while(true){
if(serial.connectedPeripheral == nil){
self.GoBackToBLE()
}
}
}
}
I want to precise that i can't use the method dispatch_get_main_queue because if i use that i can't do anything else into the view for example if i have a button I want to be able to press it and if i use dispatch_get_main_queue method i can't.
any suggestions? thanks a lot

Answer 1

You shouldn't do anything related to UI in dispatch_get_global_queue
you can split the things to run into 2 parts, 1 is related to UI other one is doing network calls/calculations etc.
override func viewDidLoad(){
super.ViewDidLoad()
let priority = DISPATCH_QUEUE_PRIORITY_DEFAULT
dispatch_async(dispatch_get_main_queue(), { () -> Void in
// do the ui stuff here
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), { () -> Void in
// do everything which is not ui
})
})
}