Xamarin.forms: System.NullReferenceException: in Platform.LayoutRootPage

[mfeingol]

Description

Crash in Xamarin Forms navigating from one page to another via hamburger menu. Not sure how actionable this is, unfortunately.

Here's the crash report stack trace from AppCenter:

Platform.LayoutRootPage (Xamarin.Forms.Page page, System.Int32 width, System.Int32 height)
System.NullReferenceException: Object reference not set to an instance of an object

Platform.LayoutRootPage (Xamarin.Forms.Page page, System.Int32 width, System.Int32 height)
IPlatformLayout.OnLayout (System.Boolean changed, System.Int32 l, System.Int32 t, System.Int32 r, System.Int32 b)
PlatformRenderer.OnLayout (System.Boolean changed, System.Int32 l, System.Int32 t, System.Int32 r, System.Int32 b)
ViewGroup.n_OnLayout_ZIIII (System.IntPtr jnienv, System.IntPtr native__this, System.Boolean changed, System.Int32 l, System.Int32 t, System.Int32 r, System.Int32 b)
(wrapper dynamic-method) System.Object.35(intptr,intptr,bool,int,int,int,int)

Steps to Reproduce

Navigating from one page to another in my app. Not reproducible with all pages. Reproduced several times (but not always) navigating from a settings page containing a tableview to a page with pivots containing listviews.

Expected Behavior

Actual Behavior

Basic Information

• Version with issue: 3.2.0.839982
• Last known good version: Unclear
• IDE: VS 2017 15.8.6
• Platform Target Frameworks:
  
  
  
  • Android: 8.1
  
  
• Android Support Library Version: 27.0.2.1
• Nuget Packages:
• Affected Devices: LG V30 w/ Android 8.0

Screenshots

Reproduction Link

[kingces95]

C# void LayoutRootPage(Page page, int width, int height) { var activity = (FormsAppCompatActivity)_context; page.Layout(new Rectangle(0, 0, activity.FromPixels(width), activity.FromPixels(height))); }

[kingces95]

Gonna approve this even tho there's no reproduction. If nothing else, we could throw argument null exceptions to discover if it's the page or activity that's null.

[milanio]

We are hitting exactly the same problem. No more information that the stack trace above. The worst thing is that it happens only sometimes and it's very hard to reproduce. However it happens often enough to annoy the users of the app.

[zekeinferno]

My team and I are also encountering an NRE while navigating about the app using Prism navigation. We are still investigating the issue however one thing we have been able to determine is that it started from version 3.1.0.697729 and onwards. Issue #4051 may be the same issue as this one.

[zekeinferno]

I have created Issue #4403 with a reproduction project related to my previous comment. Keeping these issues linked in case they're the same issue.

[samhouts]

@mfeingol @milanio @zekeinferno Are you still experiencing this issue? Thanks!

[milanio]

@samhouts No, I haven't seen this one for a while.