Hi I have been getting random null reference exceptions in my app when running on lower end devices (galaxy ace in this case), but not on a desire s or emulators. They mostly seem to be in and around my data access to sqlite (using sqlite-net) although I haven't been able to pin point them to any one bit of code. Generally it will crash with the only stacktrace being that there was a null reference exception and nothing to indicate where and so I have been using logging to try to get an idea of the source of the issues but it seems to shift around. Then today the debugger actually caught one of these occurences but when checking out the variables in scope 'this' was null (I have a screen shot if you would like it as in theory this isn't possible). 'this' being a singleton instance of a class which was running some data updates on a background thread (started from my activity using ThreadPool.QueueUserWorkItem(state => _dp.CheckCacheAge()); ). At this point there is not a lot going on in the current activity which is simply waiting on the updates and has some event handlers attached to update the ui with progress. This particular crash happened at a point where there is not a great deal loaded into memory.
stacktrace: System.NullReferenceException: Object reference not set to an instance of an object at (wrapper stelemref) object:virt_stelemref_class (intptr,object) at MyDevon.DataProvider.PopulateConfiguration () [0x0001b] in /Projects/NVG/Around Me Android/branches/My Devon/Around Me/DataAccess/DataProvider.cs:225 The log from another occurence (included last reference to garbage collection): 06-25 11:22:09.119: D/Mono ( 3076): GC_MINOR: pause 37.06ms, bridge 0.00ms promoted 912K major 5008K los 7416K ..... 06-25 11:22:09.659: D/SQLite(3076): ExecuteNonQuery 06-25 11:22:09.659: D/SQLite(3076): ExecuteNonQuery 06-25 11:22:09.659: D/SQLite(3076): ExecuteNonQuery 06-25 11:22:09.669: D/MD-DataProvider(3076): started insert 06-25 11:22:09.669: D/SQLite(3076): ExecuteNonQuery 06-25 11:22:09.669: I/mono(3076): Stacktrace: 06-25 11:22:09.679: E/mono(3076): [0x7f5420:] EXCEPTION handling: System.NullReferenceException: Object reference not set to an instance of an object These crashes are intermitent as in they do not occur in the same place each time and only occur roughly 1 in every 3 runs of the full update routine. There doesn't seem to be any correlation with timings of the GC either, but it does feel like something external is killing off my static instance of this class. Any advice of where to look on this one would be very helpful as I'm completely at a loss. thanks Keith -- View this message in context: http://mono-for-android.1047100.n5.nabble.com/this-is-null-null-reference-exception-tp5710505.html Sent from the Mono for Android mailing list archive at Nabble.com. _______________________________________________ Monodroid mailing list Monodroid@lists.ximian.com UNSUBSCRIBE INFORMATION: http://lists.ximian.com/mailman/listinfo/monodroid
