Open Radar

 
Area:
UIKit

Summary:
I have a scenario whereas I need to add a VC as a childViewController to the app that has a UITabBarController as its rootViewController. Without getting into too much detail about why, think "tooltip" or "overlay".

If that UITabBarController happens to have 5 tabs, the viewWillTransition:to:with: method of the childViewController does not called on various rotations of the device - if the device is an iPad Air 2 and the split screen is setup as 2/3.

I created an example project that demonstrates this problem. The green rectangle should maintain a width that follows the width of the window. After several rotations the landscape mode will not have the transition method called.

This only happens on 2/3 split (in landscape)

"Initial Screen.png" - show the example at just after I start the app
"Bad.png" - shows the app in a bad state after a few rotations
"After Some Rotation.png" - this screenshot shows that the 5th tab is now the "more" button which is incorrectly being shown.

Steps to Reproduce:
1. uncompress the example project
2. build the example project
3. run the example app
4. setup the 2/3 split
5. start rotating the app a few times
6. stop on the second time you get to landscape mode 
7. observe the size of the green rectangle is wrong.

Expected Results:
viewWillTransition:to:for should be called all the time.

Actual Results:
viewWillTransition:to:for not getting called when there are 5 tabs in the UITabBarController AND rotated several times in 2/3 split mode.

Version:
iOS 10.3 Simulator and iOS 10.3.1 device

Notes:


Configuration:
iPad Air 2 (2/3 split)

Attachments:
'BAD.png', 'TestTabControllerTransition.zip', 'After Some Rotation.png' and 'Initial Screen.png' were successfully uploaded.