Android app crashes on startup

[AzuxirenLeadGuy]

I am building the avalonia.xplat application for android. When I run it on the Debug configuration in Visual Studio, It runs fine. However, if I close the debugging session and run the app again on the android emulator, it crashes on startup. Similarly, if I build and deploy it on the Release configuration, the app is deployed but it crashes on startup.

EDIT:

This video shows what I see while I run it:

Thanks to @timunie , The exception message is known. It is as shown

System.InvalidOperationException: Invalid size returned for Measure.
   at Avalonia.Layout.Layoutable.Measure(Size availableSize)
   at Avalonia.Layout.Layoutable.MeasureOverride(Size availableSize)
   at Avalonia.Layout.Layoutable.MeasureCore(Size availableSize)
   at Avalonia.Layout.Layoutable.Measure(Size availableSize)
   at Avalonia.Layout.Layoutable.MeasureOverride(Size availableSize)
   at Avalonia.Controls.Embedding.EmbeddableControlRoot.MeasureOverride(Size availableSize)
   at Avalonia.Layout.Layoutable.MeasureCore(Size availableSize)
   at Avalonia.Layout.Layoutable.Measure(Size availableSize)
   at Avalonia.Layout.LayoutManager.Measure(ILayoutable control)
   at Avalonia.Layout.LayoutManager.Measure(ILayoutable control)
   at Avalonia.Layout.LayoutManager.Measure(ILayoutable control)
   at Avalonia.Layout.LayoutManager.Measure(ILayoutable control)
   at Avalonia.Layout.LayoutManager.Measure(ILayoutable control)
   at Avalonia.Layout.LayoutManager.ExecuteMeasurePass()
   at Avalonia.Layout.LayoutManager.InnerLayoutPass()
   at Avalonia.Layout.LayoutManager.ExecuteLayoutPass()
   at Avalonia.Controls.TopLevel.HandleResized(Size clientSize, PlatformResizeReason reason)
   at Avalonia.Android.Platform.SkiaPlatform.TopLevelImpl.OnResized(Size size)
   at Avalonia.Android.AvaloniaView.ViewImpl.OnResized(Size size)
   at Avalonia.Android.Platform.SkiaPlatform.TopLevelImpl.ViewImpl.Android.Views.ISurfaceHolderCallback.SurfaceChanged(ISurfaceHolder holder, Format format, Int32 width, Int32 height)
   at Android.Views.ISurfaceHolderCallbackInvoker.n_SurfaceChanged_Landroid_view_SurfaceHolder_III(IntPtr jnienv, IntPtr native__this, IntPtr native_holder, Int32 native_format, Int32 width, Int32 height)

Please let me know how to solve this. Thanks in advance.

[timunie]

Hi

Without an error message it's not really possible to help you here. I think you can understand that. But I think you also don't see an error, instead your App just crashes.

But I have good news, you can log unhandled exceptions and write them to a log file for example. https://docs.avaloniaui.net/docs/getting-started/unhandledexceptions

I hope this helps.

Happy coding
Tim

[timunie]

Can you show me how you are trying to catch the exception and write it to the log file?
https://docs.avaloniaui.net/docs/getting-started/unhandledexceptions#the-global-try-catch

[AzuxirenLeadGuy]

Can you show me how you are trying to catch the exception and write it to the log file?

I did read the link you showed me, and I initially tried putting the contents CustomizeAppBuilder() inside a try-catch block and writing the exception message to a file, but the error was not thrown there, so I didn't get anything from that step. I couldn't understand how to edit the program from the link you showed me, since I could not figure out a single method (like the usual Main() function) which contained the entire execution and then put it in a try-catch block.

I changed the MainActivity class which originally contained

    public class MainActivity : AvaloniaActivity<App>
    {
        protected override AppBuilder CustomizeAppBuilder(AppBuilder builder)
        {
            return base.CustomizeAppBuilder(builder);
        }
    }

I noticed that in the Avalonia.Desktop program, the LogToTrace() method was called to store all log information, so I figured that it would be good if I could write the log information to a file. So I changed it to this

    public class MainActivity : AvaloniaActivity<App>
    {
        protected override AppBuilder CustomizeAppBuilder(AppBuilder builder)
        {
            string filename = GetExternalFilesDir(string.Empty) + "/tracelog.txt";
            System.Diagnostics.Trace.Listeners.Add
                (
                new System.Diagnostics.TextWriterTraceListener(filename) 
                { 
                    Filter = new System.Diagnostics.EventTypeFilter(System.Diagnostics.SourceLevels.All),
                    TraceOutputOptions = (System.Diagnostics.TraceOptions)63
                }
                );
            System.Diagnostics.Trace.Listeners.Remove("Default");
            return base.CustomizeAppBuilder(builder).LogToTrace(Avalonia.Logging.LogEventLevel.Debug);
        }
    }

I am using the LogToTrace() method which logs all information to the sink in System.Diagnostics. I then added a TraceListener to write all the log output to a file. I followed this guide

Do let me know if I'm making a silly mistake anywhere.

[timunie]

Good point. It's just available for Desktop and also for iOS but seems like it's not for Android. Now I have no other idea. Sorry.

[timunie]

Maybe you can have a look how Xamarin does it https://stackoverflow.com/questions/48499328/how-to-catch-all-exceptions-in-try-catch-block-in-xamarin-android

Disclaimer: I am not a member of Avalonia, so someone of the core team still may have a solution.

[AzuxirenLeadGuy]

Alright. I'll try this out.

Thanks for your responses BTW. I really appreciate it.

EDIT: This was very helpful. I am finally able to view the exception message. I have updated the title. Thank you for your help.

[danwalmsley]

@AzuxirenLeadGuy something in your ui isnt measuring correctly... you have some embedded native controls?