Bug 38292 - JavaProxyThrowable: System.NullReferenceException triggered by GestureDetector
Summary: JavaProxyThrowable: System.NullReferenceException triggered by GestureDetector
Status: RESOLVED NORESPONSE
Alias: None
Product: Forms
Classification: Xamarin
Component: Forms ()
Version: unspecified
Hardware: Other Mac OS
: --- normal
Target Milestone: ---
Assignee: Paul DiPietro [MSFT]
URL:
Depends on:
Blocks:
 
Reported: 2016-02-02 10:10 UTC by Kasper
Modified: 2017-06-19 17:40 UTC (History)
6 users (show)

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

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Status:
RESOLVED NORESPONSE

Description Kasper 2016-02-02 10:10:34 UTC
Seen in XF 2.1.0-pre3 on Nexus 5X running Android 6.0.1.

Happens occasionally, when moving up and down the page stack. It seems to be a race condition of some sort.

Here is a transcript from adb logcat:

02-02 10:58:57.471 18080 18080 I mono-stdout: RootDomain
02-02 10:58:57.472 18080 18080 I mono-stdout: System.UnhandledExceptionEventArgs
02-02 10:58:57.493 18080 18080 E AndroidRuntime: FATAL EXCEPTION: main
02-02 10:58:57.493 18080 18080 E AndroidRuntime: Process: XamarinPoC.Android, PID: 18080
02-02 10:58:57.493 18080 18080 E AndroidRuntime: java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
02-02 10:58:57.493 18080 18080 E AndroidRuntime: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
02-02 10:58:57.493 18080 18080 E AndroidRuntime: Caused by: java.lang.reflect.InvocationTargetException
02-02 10:58:57.493 18080 18080 E AndroidRuntime: 	at java.lang.reflect.Method.invoke(Native Method)
02-02 10:58:57.493 18080 18080 E AndroidRuntime: 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
02-02 10:58:57.493 18080 18080 E AndroidRuntime: 	... 1 more
02-02 10:58:57.493 18080 18080 E AndroidRuntime: Caused by: md52ce486a14f4bcd95899665e9d932190b.JavaProxyThrowable: System.NullReferenceException: Object reference not set to an instance of an object
02-02 10:58:57.493 18080 18080 E AndroidRuntime:   at Xamarin.Forms.Platform.Android.InnerGestureListener.Android.Views.GestureDetector.IOnGestureListener.OnScroll (Android.Views.MotionEvent e1, Android.Views.MotionEvent e2, Single distanceX, Single distanceY) <0xcb192cb8 + 0x000a8> in <filename unknown>:0 
02-02 10:58:57.493 18080 18080 E AndroidRuntime:   at Android.Views.GestureDetector+IOnGestureListenerInvoker.n_OnScroll_Landroid_view_MotionEvent_Landroid_view_MotionEvent_FF (IntPtr jnienv, IntPtr native__this, IntPtr native_e1, IntPtr native_e2, Single distanceX, Single distanceY) <0xcb192bb0 + 0x000db> in <filename unknown>:0 
02-02 10:58:57.493 18080 18080 E AndroidRuntime:   at (wrapper dynamic-method) System.Object:4a9d572a-911a-4b10-8625-5bf8a42f7359 (intptr,intptr,intptr,intptr,single,single)
02-02 10:58:57.493 18080 18080 E AndroidRuntime: --- End of stack trace from previous location where exception was thrown ---
02-02 10:58:57.493 18080 18080 E AndroidRuntime:   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () <0xcec18090 + 0x00024> in <filename unknown>:0 
02-02 10:58:57.493 18080 18080 E AndroidRuntime:   at Android.Runtime.JNIEnv.CallBooleanMethod (IntPtr jobject, IntPtr jmethod, Android.Runtime.JValue* parms) <0xd68865c8 + 0x000c3> in <filename unknown>:0 
02-02 10:58:57.493 18080 18080 E AndroidRuntime:   at Android.Views.GestureDetector.OnTouchEvent (Android.Views.MotionEvent ev) <0xcdab6800 + 0x0019f> in <filename unknown>:0 
02-02 10:58:57.493 18080 18080 E AndroidRuntime:   at Xamarin.Forms.Platform.Android.VisualElementRenderer`1[TElement].Android.Views.View.IOnTouchListener.OnTouch (Android.Views.View v, Android.Views.MotionEvent e) <0xcdab43a0 + 0x0016b> in <filename unknown>:0 
02-02 10:58:57.493 18080 18080 E AndroidRuntime:   at Android.Views.View+IOnTouchListenerInvoker.n_OnTouch_Landroid_view_View_Landroid_view_MotionEvent_ (IntPtr jnienv, IntPtr native__this, IntPtr native_v, IntPtr native_e) <0xcb1a0540 + 0x000a3> in <filename unknown>:0 
02-02 10:58:57.493 18080 18080 E AndroidRuntime:   at (wrapper dynamic-method) System.Object:b280fb76-7b19-44f3-822f-0e68cf967c15 (intptr,intptr,intptr,intptr)
02-02 10:58:57.493 18080 18080 E AndroidRuntime: --- End of stack trace from previous location where exception was thrown ---
Comment 1 Paul DiPietro [MSFT] 2016-02-02 14:14:59 UTC
Do you have a reproduction project which you can provide to help investigate the issue?
Comment 2 Chris King 2017-06-19 17:21:44 UTC
Assigned to you as you were last to request additional info.
Comment 3 Paul DiPietro [MSFT] 2017-06-19 17:40:33 UTC
Because we have not received a reply to our request for more information we are closing this issue. If you are still encountering this issue, please reopen the ticket and attach a project that demonstrates the issue.

Thanks!