Bug 33350 - traitCollectionDidChange throws Argument Cannot be Null
Summary: traitCollectionDidChange throws Argument Cannot be Null
Status: RESOLVED FIXED
Alias: None
Product: iOS
Classification: Xamarin
Component: General ()
Version: XI 8.99 (iOS9 previews)
Hardware: PC Mac OS
: --- normal
Target Milestone: ios9/Xcode7/OSX10.11
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2015-08-25 00:01 UTC by Cody Beyer (MSFT)
Modified: 2015-08-25 08:30 UTC (History)
2 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FIXED

Description Cody Beyer (MSFT) 2015-08-25 00:01:47 UTC
### Description

traitCollectionDidChange should allow a null parameter to be passed to it as previousTraitCollection, according to: https://developer.apple.com/library/ios/documentation/UIKit/Reference/UITraitEnvironment_Ref/#//apple_ref/occ/intfm/UITraitEnvironment/traitCollectionDidChange:

However, this will thrown an error, as demonstrated in the sample project

### Sample

https://www.dropbox.com/s/jd0ms9a8nths986/Jonathon%20Brammer%20-%20XamarinTesting.zip?dl=0

### Error

https://gist.github.com/CodyBeyer/8909c8dc206d9383c156

### Steps to Reproduce

1. Download sample
2. Run in iOS Simulator

### Expected Results

App will fully launch, showing a blank screen

### Actual results

App crashes during launch screen with above error

### Versions

=== Xamarin Studio ===

Version 5.9.5 (build 10)
Installation UUID: 8915c17c-ec61-4ec3-8f89-0683d6363abf
Runtime:
	Mono 4.0.3 ((detached/d6946b4)
	GTK+ 2.24.23 (Raleigh theme)

	Package version: 400030020

=== Apple Developer Tools ===

Xcode 6.4 (7720)
Build 6E35b

=== Xamarin.iOS ===

Version: 8.10.4.46 (Business Edition)
Hash: 2c66d2f
Branch: master
Build date: 2015-08-04 13:52:25-0400

=== Xamarin.Android ===

Version: 5.1.5.3 (Business Edition)
Android SDK: /Users/codybeyer/Library/Developer/Xamarin/android-sdk-macosx
	Supported Android versions:
		4.0.3 (API level 15)
		4.4   (API level 19)
		5.0   (API level 21)
		5.1   (API level 22)
Java SDK: /usr
java version "1.7.0_71"
Java(TM) SE Runtime Environment (build 1.7.0_71-b14)
Java HotSpot(TM) 64-Bit Server VM (build 24.71-b01, mixed mode)

=== Xamarin Android Player ===

Version: Unknown version
Location: /Applications/Xamarin Android Player.app

=== Xamarin.Mac ===

Version: 2.0.2.111 (Business Edition)

=== Build Information ===

Release ID: 509050010
Git revision: 48d16bc4f12ce3938964fc7c3d72fdc6887ad4ad
Build date: 2015-08-18 16:55:24-04
Xamarin addins: c2d51b360ad9f59e689046d47030df27de28f94a

=== Operating System ===

Mac OS X 10.10.5
Darwin BeyerStudios.local 14.5.0 Darwin Kernel Version 14.5.0
    Wed Jul 29 02:26:53 PDT 2015
    root:xnu-2782.40.9~1/RELEASE_X86_64 x86_64
Comment 1 Sebastien Pouliot 2015-08-25 08:30:10 UTC
This is already fixed in the 8.99 previews (or the next one to be released).