ykyouhei/KYDrawerController

Weird margins when using async task

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#82 opened on Jan 19, 2017

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help wantedpossible bug

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Description

I'm having problem with margins when I instantiate a view controller inside an async task.

When I do this, the view loads weird:

let priority = DISPATCH_QUEUE_PRIORITY_DEFAULT
dispatch_async(dispatch_get_global_queue(priority, 0)) {
//Web Service call
dispatch_async(dispatch_get_main_queue()) {
   let viewController = UIStoryboard(name: "Tracking", bundle: nil).instantiateViewControllerWithIdentifier("tracking") as! CarrierTrackingVC
   viewController.truckTrack = TruckTrack()
   elDrawer.mainViewController = viewController
   }
}

screen shot 2017-01-18 at 9 48 30 am

But when I do it outside the async task it looks ok: screen shot 2017-01-18 at 9 50 16 am

I'm loading it in the main thread, inside dispatch_async(dispatch_get_main_queue()) so I don't understand why it behaves like that.

viewController is a UITabBarController, each tab contains a NavigationController, and each NavigationController contains a ViewController

UITabBarController > NavigationController > ViewController

Contributor guide

Research direction
Investigate the view lifecycle and layout when a view controller is instantiated inside an async block. Check if the view is loaded before being added to the window, and verify that Auto Layout constraints are set correctly after the async callback.
Tech stack
swiftios
Domain
mobile
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
SwiftiOSGrand Central Dispatch
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65