Bug 28221 - [Android] Null Reference in custom cell renderer
Summary: [Android] Null Reference in custom cell renderer
Status: RESOLVED INVALID
Alias: None
Product: Forms
Classification: Xamarin
Component: Forms ()
Version: 1.4.1
Hardware: PC Mac OS
: High major
Target Milestone: ---
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2015-03-19 23:44 UTC by Cody Beyer (MSFT)
Modified: 2015-03-27 17:28 UTC (History)
5 users (show)

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

Notice (2018-05-24): bugzilla.xamarin.com is now in read-only mode.

Please join us on Visual Studio Developer Community and in the Xamarin and Mono organizations on GitHub to continue tracking issues. Bugzilla will remain available for reference in read-only mode. We will continue to work on open Bugzilla bugs, copy them to the new locations as needed for follow-up, and add the new items under Related Links.

Our sincere thanks to everyone who has contributed on this bug tracker over the years. Thanks also for your understanding as we make these adjustments and improvements for the future.


Please create a new report on Developer Community or GitHub with your current version information, steps to reproduce, and relevant error messages or log files if you are hitting an issue that looks similar to this resolved bug and you do not yet see a matching new report.

Related Links:
Status:
RESOLVED INVALID

Description Cody Beyer (MSFT) 2015-03-19 23:44:30 UTC
### Description

The following test contains a custom cell renderer, which worked in previous versions of Xamarin.Forms but fails on 1.4.0.6341

### Test Case

https://www.dropbox.com/s/phsixq3og7lr5pa/Xamarin.Forms.Plugins.zip?dl=0

### Error Log

https://gist.github.com/CodyBeyer/33cb8ba3db41644093a5

### Steps to reproduce

1. Download test case
2. Run SampleApp.Droid

### Expected Results

App should build and run without error

### Actual Results

App builds but throws a null reference exception at runtime

### Version

=== Xamarin Studio ===

Version 5.8 (build 443)
Installation UUID: d1ae49a4-0e18-4c19-800a-f97c5cf348b0
Runtime:
	Mono 3.12.1 ((detached/b7764aa)
	GTK+ 2.24.23 (Raleigh theme)

	Package version: 312010000

=== Apple Developer Tools ===

Xcode 6.2 (6776)
Build 6C131e

=== Xamarin.iOS ===

Version: 8.8.0.2 (Business Edition)
Hash: ccfcd59
Branch: 
Build date: 2015-03-10 02:20:32-0400

=== Xamarin.Android ===

Version: 4.20.0.37 (Business Edition)
Android SDK: /Users/beyerc/Library/Developer/Xamarin/android-sdk-macosx
	Supported Android versions:
		2.1   (API level 7)
		2.2   (API level 8)
		2.3   (API level 10)
		3.1   (API level 12)
		4.0.3 (API level 15)
		4.4   (API level 19)
		5.0   (API level 21)
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: 1.10.0.21 (Business Edition)

=== Build Information ===

Release ID: 508000443
Git revision: 73883239470cbe8e261c94d95f7c3d0452fd393b
Build date: 2015-03-10 07:22:51-04
Xamarin addins: a2ff7b617f09d9c45d8bbf3d010b5db0d7d36100

=== Operating System ===

Mac OS X 10.10.2
Darwin Codys-MacBook-Pro.local 14.1.0 Darwin Kernel Version 14.1.0
    Thu Feb 26 19:26:47 PST 2015
    root:xnu-2782.10.73~1/RELEASE_X86_64 x86_64
Comment 4 Jason Smith [MSFT] 2015-03-27 15:53:12 UTC
You extended ViewCell and not TextCell but your renderer is not managing the ViewCell.View property. Simply changing 

public class ExtendedTextCell : ViewCell

to

public class ExtendedTextCell : TextCell

fixes the issue.
Comment 5 ppatarinski@paylocity.com 2015-03-27 17:28:41 UTC
Thanks Jason. That worked. Ended up using Cell instead of TextCell. One of my coworkers figured out that the issue was due to the View property not being set and that causing the Null Ref.