SwipePanel.Run () - System.NullReferenceException: Object reference not set to an instance of an object

[Frozengnu]

We are seeing a sudden uptick in a crash coming from sfCalendar when navigating back 1 month (user reports going aug -> jul) and selecting a date. Android (8/9?) only.

Here's an example copy and pasted from App Center:

Android: 9 Android Build: HUAWEIPOT-LX1 Manufacturer: HUAWEI Model: POT-LX1 CrashReporter Key: b4cc5a85-bcc6-43fa-9bbd-cb31f09e063b Date: undefined Xamarin Exception Stack: System.NullReferenceException: Object reference not set to an instance of an object at Com.Syncfusion.Calendar.SwipePanel.Run () [0x00081] in <f8a7a9a2e43e4c41a1b2d9a2ed69cfba>:0 at System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0 (System.Object state) [0x00000] in <0a951c0b4607490bb24b709cc58587b4>:0 at Android.App.SyncContext+<>c__DisplayClass2_0.<Post>b__0 () [0x00000] in <518144de650e47a38ddec3f79172b312>:0 at Java.Lang.Thread+RunnableImplementor.Run () [0x00008] in <518144de650e47a38ddec3f79172b312>:0 at Java.Lang.IRunnableInvoker.n_Run (System.IntPtr jnienv, System.IntPtr native__this) [0x00009] in <518144de650e47a38ddec3f79172b312>:0 at (wrapper dynamic-method) Android.Runtime.DynamicMethodNameCounter.49(intptr,intptr)

[Frozengnu]

Our customers tells us, that if you tap the month name in the top left corner, and select the new month that way instead of swiping to it, then there is no crash.

[Subburaj Pandian Veluchamy]

Hi Frozengnu, 

  

Thank you for contacting Syncfusion support. 

 

Based on the provided information we have checked the mentioned exception “Swipe the calendar and select the date with MVVMCross” and we can able to replicate the mentioned exception from our end. We have logged the bug report for the same. We will fix and include the issue fix in our upcoming Volume 2 SP1 release, which is expected to roll out by mid of August 2019. We appreciate your patience until then.  

 

You can track the status of the report by the following feedback link,
  

https://www.syncfusion.com/feedback/8135/exception-was-thrown-when-swipe-the-calendar-with-mvvmcross 

Note: The provided feedback link is private, and you need to login to view this feedback. 

 

Regards,
Subburaj Pandian V  

[Padmini Ramamurthy]

From: Tim Ahrentlov 
Sent: Friday, August 9, 2019 9:21 AM
To: Syncfusion Support <[email protected]>
Subject: Re: Syncfusion support community forum 146559, SwipePanel.Run () - System.NullReferenceException: Object reference not set to an instance of an object, has been updated. 

  

Brilliant. Thanks! 

[Padmini Ramamurthy]

Hi Tim, 

  

You are welcome and we will let you know once Volume 2 SP 1 is rolled out. 

  

Regards, 

Padmini 

[Indumathi Ravichandran]

Hi Frozengnu, 

 

We are glad to announce that our Essential Studio 2019 Volume 2 SP1 Release version 17.2.0.46 is rolled out with the mentioned issue fix “Swipe the calendar and select the date with MVVMCross” and is available for download under the following link.  

 

https://www.syncfusion.com/forums/146832/essential-studio-2019-volume-2-service-pack-release-v17-2-0-46-available-for-download  

 

We thank you for your support and appreciate your patience in waiting for this release. Please get in touch with us if you would require any further assistance.  

 

Regards, 

Indumathi R 

[Frozengnu]

Sounds good.

Is the mentioning of MVVMCross in the fix a typo ? : 

• #244641 – [Android] The NullReferenceException will no longer thrown while swipe the calendar in MVVMCross framework.

  
  

[Subburaj Pandian Veluchamy]

Hi Frozengnu,  

 

Thank you for the update. 

 

No, this mentioned issue occurred only in MVVM cross. As mentioned, we have included the issue fix in our latest Volume 2 SP1 Release update version 17.2.0.46.  

 

Please upgrade to this latest update and let us know, whether the issue resolved at your end. 

 

Regards, 

Subburaj Pandian V  

[Frozengnu]

I'm using forms. Hence this thread in the forms subforum. I got the impression that the MVVMCross variant was fixed long ago.

[Subburaj Pandian Veluchamy]

Hi Frozengnu,  

   

No, the mentioned issue “Exception thrown when Swipe the calendar and select the date with MVVMCross” in Xamarin.Forms was fixed only in this latest Volume 2 SP1 release update version 17.2.0.46.

If you have any other query, please elaborate in detail. We will happy to assist you. 

 

Regards,
Subburaj Pandian V   

[Frozengnu]

Seems like this fix created a new bug that crashes the app.

Java.Lang.ClassNotFoundException: Didn't find class "md5a5ef2baa6ee16f32e6a8325e10f58559.SwipePanel" on path: DexPathList[[zip file "/data/app/com.timegnu-fajxVcT5d8fn_ioRcGaJ3g==/base.apk"],nativeLibraryDirectories=[/data/app/com.timegnu-fajxVcT5d8fn_ioRcGaJ3g==/lib/arm64, /data/app/com.timegnu-fajxVcT5d8fn_ioRcGaJ3g==/base.apk!/lib/arm64-v8a, /system/lib64, /vendor/lib64, /product/lib64]]

I've attached the crash log. Seems to happen on an Huawei Mate 10 with Android 8. Simply selecting a date now crashes the app. Same code base as before the fix where this operation worked fine.

Attachment: calender_crash_d072fc5f.zip

[Frozengnu]

I will test rolling back the new r8/d8 android feature in Xamarin.Android. I suspect that the SyncFusion nuggets are not ready for this.

[Frozengnu]

Syncfusion needs to support r8.

Rolling back r8 (keeping d8) removed the ava.Lang.ClassNotFoundException: Didn't find class "md5a5ef2baa6ee16f32e6a8325e10f58559.SwipePanel" on path: DexPathList[[zip file "/data/app/com.timegnu-fajxVcT5d8fn_ioRcGaJ3g==/base.apk"],nativeLibraryDirectories=[/data/app/com.timegnu-fajxVcT5d8fn_ioRcGaJ3g==/lib/arm64, /data/app/com.timegnu-fajxVcT5d8fn_ioRcGaJ3g==/base.apk!/lib/arm64-v8a, /system/lib64, /vendor/lib64, /product/lib64]]

[Subburaj Pandian Veluchamy]

Hi Jens, 

  

Thank you for the update. 

  

Based on the provided information, we have checked mentioned issue “Calendar crashes when selecting the date when applying the d8 DexTool” in Xamarin Android and we are unable to replicate the crash from our side. We have checked the same by adding d8/r8 DexTool in the Android project with the simple MVVMCross sample and calendar works as expected without any issue.  

 

We have attached the sample for your reference, please find the sample from following link. 

  

Samplelink:https://www.syncfusion.com/downloads/support/forum/146559/ze/MvxForms_(2)_(2)247279858.zip 

  

Please check the sample and let us know if you still facing the same issue? If not, please modify the sample based on your scenario and revert us with more details, it will helpful for us to analyze and provide you solution at the earliest. 

  

Regards,
Subburaj Pandian V  

[Frozengnu]

Sure. d8 works for me to. 

I wrote it was r8 that crashed a lot of Huawei Mate 10 devices with Android 8.

[Subburaj Pandian Veluchamy]

Hi Frozengnu, 

  

Thank you for the update. 

  

We have checked in r8 as well in both Xamarin.Android and with provided Xamarin.Forms sample. We have tested <AndroidLinkTool>r8</AndroidLinkTool> tool in simple Android and MVVMCross sample and it works fine as expected from our end.  

 

We have tested Xamarin.Android sample with our available Huawei LLD-AL20 device with Target Version as 8.0 and MVVMCross sample with 9.0 version and unable to replicate the mentioned crash from our side.  

 

We have attached the sample (Xamarin.Android) for your reference, please find the sample from following link. Use Xamarin.Forms sample from the last update. 

  

SampleLink:https://www.syncfusion.com/downloads/support/forum/146559/ze/SelectionChangedAndroid-2087022480.zip 

  

Please check the provided sample and let us know if you still facing the same issue? If not, please modify the sample based on your scenario and revert us with more details whether issue occurs only in Huawei Mate 10 device or other devices well. It will helpful for us to analyze on it and provide you the solution. 

  

Regards,
Subburaj Pandian V