Bug 25542 - Error rendering ListView when in a Grid after a Grid child binding updates
Summary: Error rendering ListView when in a Grid after a Grid child binding updates
Status: RESOLVED INVALID
Alias: None
Product: Forms
Classification: Xamarin
Component: Forms ()
Version: 1.2.3
Hardware: PC Mac OS
: Normal normal
Target Milestone: ---
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2014-12-19 17:36 UTC by John Miller [MSFT]
Modified: 2015-05-19 15:00 UTC (History)
4 users (show)

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


Attachments
Test Project (4.77 MB, application/zip)
2014-12-19 17:36 UTC, John Miller [MSFT]
Details


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Status:
RESOLVED INVALID

Description John Miller [MSFT] 2014-12-19 17:36:31 UTC
Created attachment 9151 [details]
Test Project

**Overview:**

   The attached sample demonstrates the problem. A ListViews cells render all black after a binding updates. 

**Steps to Reproduce:**

   1. Run the attached project on an Android emulator. (I used API 19 Nexus 4)
   2. Notice the label at the top, "Wait for it...". 
   3. You can scroll the list at this point and notice all the cells have the correct Cell text in them. 
   4. After 3 seconds, the label at the top will update to "Boom...". 
   5. Scroll the list and notice how the cells do not render the Cell text anymore.

**Actual Results:**

   After the binding for the Labels Text updates, the cells in the ListView do not render the content anymore. 

**Expected Results:**

   The cells should all still show "Cell" in the content. 

**Build Date & Platform:**

   XF 1.2.3
   Android

**Additional Information:**

   I also tested this with 1.3.0pre4, however it produced another issue. With 1.3.0pre4 the ListView does not scroll past the end of the screen so the cells are never re-drawn so you can't observe this behavior. 

Note* In the sample project the ListView has Grid.ColumnSpan="2". Remove this line and the issue in this report GOES AWAY and the Expected Results are shown. 

I tried an alternate layout as well with a StackLayout and no Grid and that does not reproduce the issue. It seems related to have the ListView in a Grid with a Grid.ColumnSpan value.
Comment 1 Ram Chandra 2014-12-22 04:22:30 UTC
I have checked this issue and with the help of attached sample and steps mentioned in bug description I am able to reproduce this issue.

When I deploy the sample project, everything works fine until the label at the top is not updated to "Boom..." but after 3 seconds when label is updated to "Boom..." and I scroll the list view up or down I observed that the cells in the list view do not render the content. but when I removed the Grid.ColumnSpan="2", I observed that I am not getting this behavior and application is working fine. 

Screencast: http://www.screencast.com/t/cbI157u9n

Environment Info:

Xamarin.Forms: 1.2.3.6257

=== Xamarin Studio ===

Version 5.7 (build 660)
Installation UUID: 6ea47b0d-1852-4aaf-808d-373ff0a5002b
Runtime:
	Mono 3.12.0 ((detached/c82a2e5)
	GTK+ 2.24.23 (Raleigh theme)

	Package version: 312000070

=== Apple Developer Tools ===

Xcode 6.1 (6604)
Build 6A1052d

=== Xamarin.iOS ===

Version: 8.6.0.41 (Trial Edition)
Hash: 2c57f4e
Branch: 
Build date: 2014-12-18 16:42:49-0500

=== Xamarin.Android ===

Version: 4.20.0.28 (Trial Edition)
Android SDK: /Users/jatin66/Desktop/Backup/android-sdk-macosx
	Supported Android versions:
		1.6    (API level 4)
		2.1    (API level 7)
		2.2    (API level 8)
		2.3    (API level 10)
		3.1    (API level 12)
		4.0    (API level 14)
		4.0.3  (API level 15)
		4.1    (API level 16)
		4.2    (API level 17)
		4.3    (API level 18)
		4.4    (API level 19)
		4.4.87 (API level 20)
		5.0    (API level 21)
Java SDK: /usr
java version "1.7.0_65"
Java(TM) SE Runtime Environment (build 1.7.0_65-b17)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)

=== Xamarin.Mac ===

Version: 1.10.0.18 (Starter Edition)

=== Build Information ===

Release ID: 507000660
Git revision: 6a74f9bdb90d9415b597064d815c9be38b401fee
Build date: 2014-12-18 00:38:00-05
Xamarin addins: 57be0f5e1433cb58b70ea9b52e9dc77ad791be40

=== Operating System ===

Mac OS X 10.10.0
Darwin Jatin66s-iMac.local 14.0.0 Darwin Kernel Version 14.0.0
    Fri Sep 19 00:26:44 PDT 2014
    root:xnu-2782.1.97~2/RELEASE_X86_64 x86_64
Comment 2 Jason Smith [MSFT] 2015-05-19 15:00:26 UTC
This behavior is expected