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[Bug] Android - OnDisappearing gets invoked when the app/page disappears due to external events. #15208

Open wfahnestock opened 2 years ago

wfahnestock commented 2 years ago

Description

Documentation on OnDisappearing states that this shouldn't be the case, so I'm not sure if the documentation is wrong or if this is genuinely a bug.

Steps to Reproduce

  1. Override OnDisappearing on a Page
  2. Press the home button or navigate away from the Xamarin.Forms App

Expected Behavior

Documentation states "OnDisappearing() is called when the page disappears due to navigating away from the page within the app. It is not called when the app disappears due to an event external to the app (e.g. user navigates to the home screen or another app, a phone call is received, the device is locked, the device is turned off)."

Actual Behavior

OnDisappearing is actually called when an external event described above happens. I can confirm it gets called when the device receives a phone call as well.

Basic Information

Environment

Show/Hide Visual Studio info ``` Microsoft Visual Studio Community 2019 Version 16.11.8 VisualStudio.16.Release/16.11.8+32002.261 Microsoft .NET Framework Version 4.8.04084 Installed Version: Community .NET Core Debugging with WSL 1.0 .NET Core Debugging with WSL ASP.NET and Web Tools 2019 16.11.94.52318 ASP.NET and Web Tools 2019 ASP.NET Web Frameworks and Tools 2019 16.11.94.52318 For additional information, visit https://www.asp.net/ Azure App Service Tools v3.0.0 16.11.94.52318 Azure App Service Tools v3.0.0 Azure Functions and Web Jobs Tools 16.11.94.52318 Azure Functions and Web Jobs Tools C# Tools 3.11.0-4.21403.6+ae1fff344d46976624e68ae17164e0607ab68b10 C# components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used. Common Azure Tools 1.10 Provides common services for use by Azure Mobile Services and Microsoft Azure Tools. Extensibility Message Bus 1.2.6 (master@34d6af2) Provides common messaging-based MEF services for loosely coupled Visual Studio extension components communication and integration. IntelliCode Extension 1.0 IntelliCode Visual Studio Extension Detailed Info Microsoft Azure Tools for Visual Studio 2.9 Support for Azure Cloud Services projects Microsoft Continuous Delivery Tools for Visual Studio 0.4 Simplifying the configuration of Azure DevOps pipelines from within the Visual Studio IDE. Microsoft JVM Debugger 1.0 Provides support for connecting the Visual Studio debugger to JDWP compatible Java Virtual Machines Microsoft Library Manager 2.1.113+g422d40002e.RR Install client-side libraries easily to any web project Microsoft MI-Based Debugger 1.0 Provides support for connecting Visual Studio to MI compatible debuggers Microsoft Visual Studio Tools for Containers 1.2 Develop, run, validate your ASP.NET Core applications in the target environment. F5 your application directly into a container with debugging, or CTRL + F5 to edit & refresh your app without having to rebuild the container. Mono Debugging for Visual Studio 16.10.15 (552afdf) Support for debugging Mono processes with Visual Studio. NuGet Package Manager 5.11.0 NuGet Package Manager in Visual Studio. For more information about NuGet, visit https://docs.nuget.org/ ProjectServicesPackage Extension 1.0 ProjectServicesPackage Visual Studio Extension Detailed Info Razor (ASP.NET Core) 16.1.0.2122504+13c05c96ea6bdbe550bd88b0bf6cdddf8cde1725 Provides languages services for ASP.NET Core Razor. SQL Server Data Tools 16.0.62111.25150 Microsoft SQL Server Data Tools TypeScript Tools 16.0.30526.2002 TypeScript Tools for Microsoft Visual Studio Visual Basic Tools 3.11.0-4.21403.6+ae1fff344d46976624e68ae17164e0607ab68b10 Visual Basic components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used. Visual F# Tools 16.11.0-beta.21514.6+b6c2c4f53ea3a08fa603ea93d6d2f808a62a21d1 Microsoft Visual F# Tools Visual Studio Code Debug Adapter Host Package 1.0 Interop layer for hosting Visual Studio Code debug adapters in Visual Studio Visual Studio Container Tools Extensions 1.0 View, manage, and diagnose containers within Visual Studio. Visual Studio Tools for Containers 1.0 Visual Studio Tools for Containers VisualStudio.DeviceLog 1.0 Information about my package VisualStudio.Foo 1.0 Information about my package VisualStudio.Mac 1.0 Mac Extension for Visual Studio VSColorOutput 2.73 Color output for build and debug windows - https://mike-ward.net/vscoloroutput Xamarin 16.11.000.197 (d16-11@6934992) Visual Studio extension to enable development for Xamarin.iOS and Xamarin.Android. Xamarin Designer 16.11.0.47 (remotes/origin/d16-11@e0d612363) Visual Studio extension to enable Xamarin Designer tools in Visual Studio. Xamarin Templates 16.10.5 (355b57a) Templates for building iOS, Android, and Windows apps with Xamarin and Xamarin.Forms. Xamarin.Android SDK 12.0.0.3 (d16-11/f0e3c2d) Xamarin.Android Reference Assemblies and MSBuild support. Mono: c633fe9 Java.Interop: xamarin/java.interop/d16-11@476bb5b ProGuard: Guardsquare/proguard/v7.0.1@912d149 SQLite: xamarin/sqlite/3.35.4@85460d3 Xamarin.Android Tools: xamarin/xamarin-android-tools/d16-11@87af37b Xamarin.iOS and Xamarin.Mac SDK 15.2.0.17 (738fde344) Xamarin.iOS and Xamarin.Mac Reference Assemblies and MSBuild support. ```
jfversluis commented 2 years ago

Thanks for the report! Do you see this only on Android? Did you also test iOS or UWP?

wfahnestock commented 2 years ago

Thanks for the report! Do you see this only on Android? Did you also test iOS or UWP?

Only seeing this on Android at the moment. My dev environment for iOS is currently tied up on another project, so unfortunately I cannot test on iOS on this time. I am also not developing this application for UWP so I haven't tested that either, so far it is only Android that I've noticed this happening on.

petes05 commented 2 years ago

I experienced this issue as well. OnAppearing/OnDisappearing would be called when the device's screen was turned on/off.

I got around it by setting SendAppearingEventOnResume and SendDisappearingEventOnPause to false. https://docs.microsoft.com/en-us/xamarin/xamarin-forms/platform/android/page-lifecycle-events