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.NET for Android provides open-source bindings of the Android SDK for use with .NET managed languages such as C#

License: MIT License

Makefile 0.37% C# 88.86% Java 0.48% C 0.75% F# 0.02% Shell 0.21% C++ 8.65% XSLT 0.09% CMake 0.41% CSS 0.01% Groovy 0.05% Kotlin 0.04% Batchfile 0.04% PowerShell 0.03%

xamarin-android's Introduction

.NET Android

.NET Android provides open-source bindings of the Android SDK and tooling for use with .NET managed languages such as C#. This ships as an optional .NET workload for .NET 6+ that can be updated independently from .NET in order to respond to external dependency updates like new Android platform and tooling.

While .NET Android is an essential part of MAUI, it is still fully supported to be used independently for native Android development using .NET.

This repository is also home to the classic Xamarin.Android product.

Support

.NET Android is now part of .NET 6+ and follows the same support lifecycle as the MAUI Support Lifecycle.

Support for classic Xamarin.Android will end on May 1, 2024 as per the Xamarin Support Policy:

Xamarin support will end on May 1, 2024 for all classic Xamarin SDKs. Android 13 will be the final version classic Xamarin.Android will target.

Downloads

Current

.NET Android ships as a workload through the dotnet workload system in .NET 6+. See the workload documentation for installation commands.

Classic Xamarin.Android installers are available here:

Platform	Link
Commercial Xamarin.Android 13.2.2 (d17-8) for Windows+Visual Studio 2022	Download
Commercial Xamarin.Android 13.2.2 (d17-8) for VSMac 2022	Download

Previous Releases are also available for download.

Contributing

If you are interested in fixing issues and contributing directly to the code base, please see the following:

This project has adopted the code of conduct defined by the Contributor Covenant to clarify expected behavior in our community. For more information, see the .NET Foundation Code of Conduct.

Feedback

Ask a question on Stack Overflow or Microsoft Q&A.
Request a new feature or vote for popular feature requests on Microsoft Developer Community.
File an issue in GitHub Issues.
Discuss development and design on Discord.

License

xamarin-android's People

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xamarin-android's Issues

Merge LinkAssemblies and StripEmbeddedLibraries tasks

An idea: it might be possible to improve build time by implementing striping the embedded libraries as linker step. We already load all the assemblies in the linker, so we might just strip them at the same time as well.

Expected Behavior

Strip embedded libraries in the linker. Possibly faster build times.

Actual Behavior

Stripping of embedded libraries is done as a separate target/task.

Cannot change TimePicker format

Steps to Reproduce

Turn the "Use 24-hour format" device setting off on your test device
Create a TimePicker
Change the format sometime later on (e.g. when the user clicks a button)

Expected Behavior

TimePicker displays time in new format

Actual Behavior

TimePicker still displays time in original format

Version Information

Xamarin.Forms 2.5.0.91635

Proposed Fix

I can see the problem in Xamarin.Forms.Platform.Android.TimePickerRenderer. The format is cached in OnElementChanged then never gets updated. Presumably, the format just needs to be refreshed in OnElementPropertyChanged if FormatProperty has changed.

ResolveAssemblies task wrongly uses reference assemblies

Steps to Reproduce

Get and Build repro https://github.com/marcominerva/XamarinAndroidIssue

If you instead the build log you will see that

Using "ResolveAssemblies" task from assembly "/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Build.Tasks.dll".

has few ...ref/netstandard2.0/... references which is wrong as they should never be used as an input to linker or any post compilation processing

This issue is possibly related to #1154

Expected Behavior

No error during execution.

Actual Behavior

[Mono] Assembly Loader probing location: 'System.Memory'.
[monodroid-assembly] Could not load assembly 'System.Memory' during startup registration.

Version Information

Xamarin.Android
Version: 8.1.0.25 (Visual Studio Community)
Android SDK: /Users/marek/Library/Developer/Xamarin/android-sdk-macosx
Supported Android versions:
6.0 (API level 23)
7.1 (API level 25)

SDK Tools Version: 25.2.5
SDK Platform Tools Version: 25.0.5
SDK Build Tools Version: 25.0.3

Log File

/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(1500,2): warning : Ignoring /Users/marek/.nuget/packages/system.buffers/4.4.0/ref/netstandard2.0 as it is a Reference Assembly
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(1500,2): warning : Ignoring /Users/marek/.nuget/packages/system.memory/4.4.0-preview2-25405-01/ref/netstandard2.0 as it is a Reference Assembly
/Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(1500,2): warning : Ignoring /Users/marek/.nuget/packages/system.runtime.compilerservices.unsafe/4.4.0/ref/netstandard2.0 as it is a Reference Assembly

VS bug #585873

Add the linker analyzer tool to XA

Expected Behavior

Make the linkeranalyzer.exe and a helper script available in the XA installation.

Actual Behavior

linkeranalyzer.exe is not installed.

Setting Target Version to "Use Compile" Does not set targetSdkVersion in Manifest

Steps to Reproduce

In VS or VS for Mac set Target SDK Version to "Use Compile" this is the default
Look at current manifest (does not contain: targetSdkVersion)
Compile application
Look at output of AndroidManifest.xml that is generated in obj/android, still does not contain targetSdkVersion

Expected Behavior

The Value should be set correct for the targetSdkVersion in the AndroidManifest.xml. So if I compile against 25, it should show android:targetSdkVersion="25".

Failure to do this has some not so great side effects. Material design doesn't display correct, permissions don't work correctly, and a lot more.

Actual Behavior

Nothing is set in the AndroidManifest.xml

Encountering new path escaping issues when using multidex/proguard on Windows

I'm encountering new path escaping issues on Windows due when using proguard and/or multidex in certain projects. I see a recent and seemingly related change in this area in this commit 2c2d47c.

Steps to Reproduce

Attempt to build a project with multidex and or proguard enabled.
msbuild /t:SignAndroidPackage KitKat.csproj /p:Configuration=Release /p:AndroidEnableProguard=true
https://github.com/xamarin/monodroid-samples/tree/master/KitKat

Expected Behavior

Proguard and multidex tool invocations succeed without issue on Windows.

Actual Behavior

Various path escaping issues are preventing proguard and multidex from executing successfully:

 Environment Variables passed to tool: (TaskId:339)
    PROGUARD_HOME=C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\Xamarin\Android\proguard (TaskId:339)
    JAVA_TOOL_OPTIONS=-Dfile.encoding=UTF8 (TaskId:339)
  C:\Program Files\Java\jdk1.8.0_144\\bin\java.exe -jar "C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\Xamarin\Android\proguard\lib\proguard.jar" -include "C:\Program Files (x86)\Android\android-sdk\\tools\proguard\proguard-android.txt" -include "obj\Release\proguard\proguard_xamarin.cfg" -include "obj\Release\proguard\proguard_project_references.cfg" -include "obj\Release\proguard\proguard_project_primary.cfg" -injars "obj\Release\android\bin\classes\classes.zip(!META-INF/MANIFEST.MF)";"C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\ReferenceAssemblies\Microsoft\Framework\MonoAndroid\v8.0\mono.android.jar(!META-INF/MANIFEST.MF)" -libraryjars "C:\Program Files (x86)\Android\android-sdk\platforms\android-26\android.jar" -outjars obj\Release\proguard\__proguard_output__.jar -optimizations !code/allocation/variable  (TaskId:339)
PROGUARD : error : C:\Program Files (Access is denied) [C:\xqatmp\b1b545ee\KitKat\KitKat.csproj]
  Picked up JAVA_TOOL_OPTIONS: -Dfile.encoding=UTF8 (TaskId:339)
  The command exited with code 1. (TaskId:339)
Done executing task "Proguard" -- FAILED. (TaskId:339)

ToolPath: C:\Program Files\Java\jdk1.8.0_144\\bin (TaskId:1130)
    ProguardJarPath: C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\Xamarin\Android\proguard\lib\proguard.jar (TaskId:1130)
    ProguardInputJarFilter: (!META-INF/MANIFEST.MF) (TaskId:1130)
  C:\Program Files\Java\jdk1.8.0_144\\bin\java.exe -jar "C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\Xamarin\Android\proguard\lib\proguard.jar" -injars "C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\ReferenceAssemblies\Microsoft\Framework\MonoAndroid\v7.1\mono.android.jar(!META-INF/MANIFEST.MF)";"C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\Xamarin\Android\android-support-multidex.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\0\jl\formsviewgroup.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\10\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\11\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\12\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\13\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\14\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\15\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\16\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\17\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\18\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\19\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\20\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\21\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\27\jl\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\28\jl\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\29\jl\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\30\jl\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\31\jl\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\32\jl\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\33\jl\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\34\jl\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\35\jl\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\36\jl\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\37\jl\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\38\jl\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\6\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\8\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\lp\9\jl\bin\classes.jar(!META-INF/MANIFEST.MF)";"obj\Debug\android\bin\classes\classes.zip(!META-INF/MANIFEST.MF)" -dontwarn -forceprocessing -outjars C:\agent\_work\_temp\h24rcf4d.bej.jar -libraryjars "\"C:\Program Files (x86)\Android\android-sdk\build-tools\26.0.2\lib\shrinkedAndroid.jar\"" -dontoptimize -dontobfuscate -dontpreverify -include "C:\Program Files (x86)\Android\android-sdk\build-tools\26.0.2\mainDexClasses.rules"  (TaskId:1130)
CREATEMULTIDEXMAINDEXCLASSLIST : error : Expecting class path separator ';' before '\Microsoft' in argument number 2 [C:\xqatmp\Bug15162\Bug15162\Bug15162.csproj]
  The command exited with code 1. (TaskId:1130)
Done executing task "CreateMultiDexMainDexClassList" -- FAILED. (TaskId:1130)

Version Information

XA 8.0.0.2 (d15-6)

Log File

http://xqa.blob.core.windows.net/gist/log-7c8201b17c434ec9bee20eac7ddb8f93.txt
http://xqa.blob.core.windows.net/gist/log-33e409f0ca854d3c93c92f4a9849df57.txt

There is no longer an informative error message printed when building against a platform SDK version that is not installed

Steps to Reproduce

Ensure you don't have API 27 installed, or remove/rename $(AndroidSdk)/platforms/android-27.
msbuild *.csproj /p:TargetFrameworkVersion=v8.1

Expected Behavior

An informative and actionable error message is displayed when the platform SDK you are attempting to compile against does not exist on disk:

Build FAILED.

"/Users/petercollins/git/monodroid-samples/Button/DroidButton.csproj" (default target) (1) ->
(_ValidateAndroidPackageProperties target) -> 
  /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(582,2): error : Could not find android.jar for API Level 26. This means the Android SDK platform for API Level 26 is not installed. Either install it in the Android SDK Manager (Tools > Open Android SDK Manager...), or change your Xamarin.Android project to target an API version that is installed. (/Users/petercollins/Library/Developer/Xamarin/android-sdk-macosx/platforms/android-26/android.jar missing.) [/Users/petercollins/git/monodroid-samples/Button/DroidButton.csproj]

    0 Warning(s)
    1 Error(s)

Time Elapsed 00:00:01.18

Actual Behavior

An error code XA5207 is displayed with no error message. This is a regression from d15-5.

Build FAILED.

"/Users/xamarinqa/myagent/_work/r3/a/monodroid-samples/Button/DroidButton.csproj" (SignAndroidPackage target) (1) ->
(_ValidateAndroidPackageProperties target) -> 
  /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/Android/Xamarin.Android.Common.targets(591,2): error : XA5207 [/Users/xamarinqa/myagent/_work/r3/a/monodroid-samples/Button/DroidButton.csproj]

    0 Warning(s)
    1 Error(s)

Time Elapsed 00:00:01.27

Version Information

XA d15-6 (8.2.0.0)

Log File

http://xqa.blob.core.windows.net/gist/log-50a50d738cd544ed9e61ed3764e9b6f7.txt

Cannot serialize abstract class on Android

Copied from JamesNK/Newtonsoft.Json#1514 @skarllot

I getting in trouble to serialize abstract class that implements binary serialization on Android (NETStandard 1.3), but on desktop works as expected.

A minimum test project was created at: https://github.com/skarllot/JsonNetAbstractClass

Source/destination types

    [Serializable]
    public abstract class BaseClass : ISerializable
    {
        protected BaseClass()
        {
        }
        
        protected BaseClass(SerializationInfo info, StreamingContext context)
        {
        }
        
        void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)
        {
            if (info == null)
                throw new ArgumentNullException(nameof(info));

            InternalGetObjectData(info, context);
        }
        
        protected abstract void InternalGetObjectData(SerializationInfo info, StreamingContext context);
    }

    [Serializable]
    public sealed class Collection : BaseClass
    {
        private readonly List<BaseClass> children;

        public Collection()
        {
            children = new List<BaseClass>();
        }

        private Collection(SerializationInfo info, StreamingContext context)
            : base(info, context)
        {
            // omitted
        }

        public IEnumerable<BaseClass> Children => children;

        public int Count => children.Count;

        // omitted
    }

    [Serializable]
    public class Termination : BaseClass
    {
        public int Value { get; set; }
        // omitted
    }

Source/destination JSON

On desktop gets:

{
   "Children":{
      "$type":"JsonNetAbstractClass.BaseClass[], DesktopJsonNetAbstractClass",
      "$values":[
         {
            "$type":"JsonNetAbstractClass.Termination, DesktopJsonNetAbstractClass",
            "Value":10
         },
         {
            "$type":"JsonNetAbstractClass.Termination, DesktopJsonNetAbstractClass",
            "Value":20
         }
      ]
   }
}

Expected behavior

Serialize same type on both platforms.

Actual behavior

Throws InvalidOperationException: Can't compile a NewExpression with a constructor declared on an abstract class.

Trace writer output:

2017-11-21T21:33:50.088 Info Started serializing JsonNetAbstractClass.Collection. Path ''.
2017-11-21T21:33:50.128 Info Started serializing JsonNetAbstractClass.BaseClass[]. Path 'Children'.
2017-11-21T21:33:50.133 Verbose Writing type name 'JsonNetAbstractClass.BaseClass[], PortableJsonNetAbstractClass' for JsonNetAbstractClass.BaseClass[]. Path 'Children'.
2017-11-21T21:33:50.136 Error Error serializing JsonNetAbstractClass.Collection. Can't compile a NewExpression with a constructor declared on an abstract class. Path 'Children.$values'.
2017-11-21T21:35:33.760 Error Error trying to serialize object

Steps to reproduce

var stringWriter = new StringWriter();
var collection = new Collection();
collection.Add(new Termination(10));
collection.Add(new Termination(20));

var traceWriter = new MemoryTraceWriter();
var serializer = JsonSerializer.CreateDefault();
serializer.TypeNameHandling = TypeNameHandling.Auto;
serializer.TraceWriter = traceWriter;
serializer.Serialize(stringWriter, collection);

GREF logging is broken in multi-process apps

Scenario: Create a Xamarin.Android app, add a e.g. Service, and set ServiceAttribute.Process:

[Service(Process="example")]
public class MyService : Android.App.Service {
    // ...
}

The problem is that the debug.mono.log system property is read at process startup -- for both (all) processes, the "normal" one and the "example" one, and they don't know to cooperate with each other.

The result is that they each write to grefs.txt, corrupting the contents.

Xamarin Android - JsonSerializationException: Error getting value from '[FIELD]' on '[METHOD]'

Copied from JamesNK/Newtonsoft.Json#1537 @lorisgiglio

Environment

Visual Studio 2015
Xamarin 4.8.0.754
Xamarin Android 8.1.0.13
Xamarin Android SDK 8.1.1.1
Newtonsoft.Json 10.0.3

Source/destination types

    public class c1
    {
        public string field1 { get; set; }
    }

Expected behavior

It has to serialize the simple object

Actual behavior

12-13 10:49:28.412 9122 9122 I MonoDroid: UNHANDLED EXCEPTION:
12-13 10:49:28.419 9122 9122 I MonoDroid: Newtonsoft.Json.JsonSerializationException: Error getting value from 'field1' on 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'. ---> System.MissingMethodException: Method 'System.Reflection.Emit.DynamicMethod.set_ProfileAPICheck' not found.
12-13 10:49:28.419 9122 9122 I MonoDroid: at System.Linq.Expressions.Compiler.LambdaCompiler.Compile (System.Linq.Expressions.LambdaExpression lambda, System.Runtime.CompilerServices.DebugInfoGenerator debugInfoGenerator) [0x0000f] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at System.Linq.Expressions.LambdaExpression.Compile () [0x00000] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.Utilities.ExpressionReflectionDelegateFactory.CreateGet[T] (System.Reflection.PropertyInfo propertyInfo) [0x0007c] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.Utilities.ReflectionDelegateFactory.CreateGet[T] (System.Reflection.MemberInfo memberInfo) [0x0000a] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.Serialization.ExpressionValueProvider.GetValue (System.Object target) [0x0000e] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: --- End of inner exception stack trace ---
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.Serialization.ExpressionValueProvider.GetValue (System.Object target) [0x00054] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.CalculatePropertyValues (Newtonsoft.Json.JsonWriter writer, System.Object value, Newtonsoft.Json.Serialization.JsonContainerContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonProperty property, Newtonsoft.Json.Serialization.JsonContract& memberContract, System.Object& memberValue) [0x00066] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject (Newtonsoft.Json.JsonWriter writer, System.Object value, Newtonsoft.Json.Serialization.JsonObjectContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract collectionContract, Newtonsoft.Json.Serialization.JsonProperty containerProperty) [0x0008d] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue (Newtonsoft.Json.JsonWriter writer, System.Object value, Newtonsoft.Json.Serialization.JsonContract valueContract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerProperty) [0x000b0] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize (Newtonsoft.Json.JsonWriter jsonWriter, System.Object value, System.Type objectType) [0x00079] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.JsonSerializer.SerializeInternal (Newtonsoft.Json.JsonWriter jsonWriter, System.Object value, System.Type objectType) [0x00253] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.JsonSerializer.Serialize (Newtonsoft.Json.JsonWriter jsonWriter, System.Object value, System.Type objectType) [0x00000] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.JsonConvert.SerializeObjectInternal (System.Object value, System.Type type, Newtonsoft.Json.JsonSerializer jsonSerializer) [0x00028] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.JsonConvert.SerializeObject (System.Object value, System.Type type, Newtonsoft.Json.JsonSerializerSettings settings) [0x00007] in :0
12-13 10:49:28.419 9122 9122 I MonoDroid: at Newtonsoft.Json.JsonConvert.SerializeObject (System.Object value, Newtonsoft.Json.JsonSerializerSettings settings) [0x00000] in :0

Steps to reproduce

    public static string GetData(string s1)
    {
       if (string.IsNullOrWhiteSpace(s1)) return null;

        c1 c = new c1();

        c1.field1 = s1;

        string res = JsonConvert.SerializeObject(c1);
        
        return res;
   }

FormsAppCompatActivity.OnDestroy occasionally throws "No view found for id" exception for Android N devices

Steps to Reproduce

I could not reproduce this from our development environment. We've received infrequent and non-critical reports from our bug reporting.

Expected Behavior

App gracefully closes

Actual Behavior

App crashes with the below exception

Version Information

Affected Form versions:
2.4.0.38779
2.5.0.91635

Affected Device Platforms:
Android N (7.x)

Affected Devices:
Galaxy S7, S7 Edge, S8, S8+
Galaxy Note 5
LG Aristo, G6, Stylo 3

https://forums.xamarin.com/discussion/104160/issue-with-forms-2-4-0-280-on-an-android-no-view-found-for-id-0x1-unknown-for-fragment (our app only initializes during FormsAppCompatActivity.OnCreate)

Stacktrace

Java.Interop.JniEnvironment No view found for id 0x1 (unknown) for fragment FragmentContainer{460ecc1 #1 id=0x1}
Raw
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()<b5f2483a551b45a99f04c68f14fc2c14>:0
Java.Interop.JniEnvironment.InstanceMethods.CallNonvirtualVoidMethod(JniObjectReference instance, JniObjectReference type, JniMethodInfo method, JniArgumentValue* args)<eba4edc4e27949518f7bf237cb1196cc>:0
Java.Interop.JniPeerMembers.JniInstanceMethods.InvokeVirtualVoidMethod(string encodedMember, IJavaPeerable self, JniArgumentValue* parameters)<eba4edc4e27949518f7bf237cb1196cc>:0
Android.App.Activity.OnDestroy()<bec3773976364d6f966ebdab5e7a8df3>:0
Xamarin.Forms.Platform.Android.FormsAppCompatActivity.OnDestroy()<8d6936257ac5419f8be9df07a9bb5129>:0
iSurvey.Android.MainActivity.OnDestroy()<8d9b18b497204292ba1e24a705032810>:0
Android.App.Activity.n_OnDestroy(IntPtr jnienv, IntPtr native__this)<bec3773976364d6f966ebdab5e7a8df3>:0
at (wrapper dynamic-method) System.Object:ee7a2513-7ba6-47d4-b295-16c9cfe08d94 (intptr,intptr)
--- End of managed Java.Lang.IllegalArgumentException stack trace ---
java.lang.IllegalArgumentException: No view found for id 0x1 (unknown) for fragment FragmentContainer{460ecc1 #1 id=0x1}
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1334)
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1569)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1636)
at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:758)
at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2415)
at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2201)
at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2155)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2064)
at android.support.v4.app.FragmentManagerImpl.dispatchDestroy(FragmentManager.java:3026)
at android.support.v4.app.FragmentController.dispatchDestroy(FragmentController.java:262)
at android.support.v4.app.FragmentActivity.onDestroy(FragmentActivity.java:390)
at android.support.v7.app.AppCompatActivity.onDestroy(AppCompatActivity.java:209)
iSurvey.Android.MainActivity.n_onDestroy(Native Method)
at iSurvey.Android.MainActivity.onDestroy(MainActivity.java:114)
at android.app.Activity.performDestroy(Activity.java:6959)
at android.app.Instrumentation.callActivityOnDestroy(Instrumentation.java:1154)
at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:4289)
at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:4320)
at android.app.ActivityThread.-wrap6(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6310)
java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:872)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:762)

Thread.CurrentPrincipal not flowing via Task.Run but does flow with Task.Factory.StartNew long running

Steps to Reproduce

Within an Xamarin.Android application, on the Main Thread, Set Thread.CurrentPrincipal to a custom Principle which is serializable.
await a Task.Run()
Inside the Task, if it executes on the same thread then Thread.CurrentPrincipal is still set correctly.
Inside the Task, if it is executing on a different thread from the main thread, it's Thread.CurrentPrincipal value is lost (it's a GenericPrincipal again).

If you do the same, but use Task.Factory.StartNew with TaskCreationOptions.LongRunning, instead of Task.Run, then the Custom Principal does flow to the new thread.

Is this a bug?

Logged stack overflow here: https://stackoverflow.com/questions/47926132/xamarin-android-task-run-vs-task-factory-startnew-and-thread-currentprincipal

               // on main thread.
                var threadId = Thread.CurrentThread.ManagedThreadId; // == 1              
                var principle = Thread.CurrentPrincipal; // == Custom Principle set earlier via login screen.

                await Task.Run(() =>
                {

                    var afterThreadId = Thread.CurrentThread.ManagedThreadId; // != 1 (i.e different thread.)
                    var afterPriniple = Thread.CurrentPrincipal; // == != Custom Principle has not flowed.
                  
                });

This is different from the behaviour exhibited by .NET 4.7 (haven't tried other .NET framework versions).

Here is a unit test that passes under .NET 4.7 and fails under Xamarin.Android

        [Fact]
        public async Task LoginService_WhenUserLogsIn_PrincipalFlowsToAsyncTask()
        {    

            var mockIdentity = new MockIdentity(true);
            var mockPrincipal = new MockPrincipal(mockIdentity);          
            Thread.CurrentPrincipal = mockPrincipal ;          

            await Task.Factory.StartNew(async () =>
            {
                var newThreadId = Thread.CurrentThread.ManagedThreadId; // on different thread.
                Assert.True(Thread.CurrentPrincipal.Identity.IsAuthenticated);
                Assert.Equal(mockPrincipal, Thread.CurrentPrincipal);
               
                await Task.Factory.StartNew(() =>
                {
                     // still works even when nesting..
                    newThreadId = Thread.CurrentThread.ManagedThreadId;
                    Assert.True(Thread.CurrentPrincipal.Identity.IsAuthenticated);
                    Assert.Equal(mockPrincipal, Thread.CurrentPrincipal);

                }, TaskCreationOptions.LongRunning);

            }, TaskCreationOptions.LongRunning);

            await Task.Run(() =>
            {
               // Following works on NET4.7 and fails under Xamarin.Android.
                var newThreadId = Thread.CurrentThread.ManagedThreadId;
                Assert.True(Thread.CurrentPrincipal.Identity.IsAuthenticated);
                Assert.Equal(mockPrincipal, Thread.CurrentPrincipal);

            });

        }

Expected Behavior

Custom CurrentPrincipal should flow via Execution Context

Actual Behavior

Custom CurrentPrincipal isn't flowing..

Version Information

Microsoft Visual Studio Professional 2017
Version 15.5.2
VisualStudio.15.Release/15.5.2+27130.2010
Microsoft .NET Framework
Version 4.7.02556

Installed Version: Professional

Visual Basic 2017 00369-60000-00001-AA768
Microsoft Visual Basic 2017

Visual C# 2017 00369-60000-00001-AA768
Microsoft Visual C# 2017

Visual C++ 2017 00369-60000-00001-AA768
Microsoft Visual C++ 2017

Visual F# 4.1 00369-60000-00001-AA768
Microsoft Visual F# 4.1

.NET Portability Analyzer 1.1.10808.0
Evaluates portability of assemblies across .NET platforms.

Application Insights Tools for Visual Studio Package 8.10.01106.1
Application Insights Tools for Visual Studio

ASP.NET and Web Tools 2017 15.0.31125.0
ASP.NET and Web Tools 2017

ASP.NET Core Razor Language Services 1.0
Provides languages services for ASP.NET Core Razor.

ASP.NET Web Frameworks and Tools 2017 5.2.51007.0
For additional information, visit https://www.asp.net/

Azure App Service Tools v3.0.0 15.0.31106.0
Azure App Service Tools v3.0.0

Common Azure Tools 1.10
Provides common services for use by Azure Mobile Services and Microsoft Azure Tools.

JavaScript Language Service 2.0
JavaScript Language Service

JavaScript Project System 2.0
JavaScript Project System

JavaScript UWP Project System 2.0
JavaScript UWP Project System

Merq 1.1.17-rc (cba4571)
Command Bus, Event Stream and Async Manager for Visual Studio extensions.

Microsoft Azure Tools 2.9
Microsoft Azure Tools for Microsoft Visual Studio 2017 - v2.9.51120.3

Microsoft Continuous Delivery Tools for Visual Studio 0.3
Simplifying the configuration of continuous build integration and continuous build delivery 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 MI-Based Debugger 1.0
Provides support for connecting Visual Studio to MI compatible debuggers

Microsoft Visual C++ Wizards 1.0
Microsoft Visual C++ Wizards

Microsoft Visual Studio Tools for Containers 1.1
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.

Microsoft Visual Studio VC Package 1.0
Microsoft Visual Studio VC Package

Mono Debugging for Visual Studio 4.8.4-pre (3fe64e3)
Support for debugging Mono processes with Visual Studio.

NuGet Package Manager 4.5.0
NuGet Package Manager in Visual Studio. For more information about NuGet, visit http://docs.nuget.org/.

SettingsWindow Extension 1.0
SettingsWindow Visual Studio Extension Detailed Info

SQL Server Data Tools 15.1.61710.120
Microsoft SQL Server Data Tools

TypeScript Tools 15.5.11025.1
TypeScript Tools for Microsoft Visual Studio

Visual Studio Code Debug Adapter Host Package 1.0
Interop layer for hosting Visual Studio Code debug adapters in Visual Studio

Visual Studio Tools for CMake 1.0
Visual Studio Tools for CMake

Visual Studio Tools for Universal Windows Apps 15.0.27128.01
The Visual Studio Tools for Universal Windows apps allow you to build a single universal app experience that can reach every device running Windows 10: phone, tablet, PC, and more. It includes the Microsoft Windows 10 Software Development Kit.

VisualStudio.Mac 1.0
Mac Extension for Visual Studio

Xamarin 4.8.0.753 (6575bd113)
Visual Studio extension to enable development for Xamarin.iOS and Xamarin.Android.

Xamarin Designer 4.8.188 (c5813fa34)
Visual Studio extension to enable Xamarin Designer tools in Visual Studio.

Xamarin.Android SDK 8.1.0.25 (HEAD/d8c6e504f)
Xamarin.Android Reference Assemblies and MSBuild support.

Xamarin.iOS and Xamarin.Mac SDK 11.6.1.2 (6857dfc)
Xamarin.iOS and Xamarin.Mac Reference Assemblies and MSBuild support.

Log File

The above command doesn't work on Windows using VS.

Random NullReference and InvalidCast crashes in mono class libraries

Steps to Reproduce

We have a big game that communicates with server via HTTP.

<AndroidLinkMode>SdkOnly</AndroidLinkMode>
<AotAssemblies>True</AotAssemblies>
<EnableLLVM>True</EnableLLVM>
<AndroidEnableSGenConcurrent>false</AndroidEnableSGenConcurrent>

GCBridge - default, it is tarjan in this XA version.

Actual Behavior

Most of the crashes come from SSL/TLS stack, but List.Add, Dictionary.Add also crash for some users, but 50 times less often.

Crashes on Androids:

Xamarin caused by: android.runtime.JavaProxyThrowable: System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper remoting-invoke-with-check) Mono.Security.Protocol.Tls.SslStreamBase:set_CheckCertRevocationStatus (bool)

Xamarin caused by: android.runtime.JavaProxyThrowable: System.NullReferenceException: Object reference not set to an instance of an object
  at Mono.Security.Protocol.Tls.SslClientStream.add_ServerCertValidation2 (Mono.Security.Protocol.Tls.CertificateValidationCallback2 value) <0x9d0ee038 + 0x0005c> in <cdde401f4fc64c87a9a513ce5f60d5ad>:0 
  at (wrapper remoting-invoke-with-check) Mono.Security.Protocol.Tls.SslClientStream:add_ServerCertValidation2 (Mono.Security.Protocol.Tls.CertificateValidationCallback2)

Xamarin caused by: android.runtime.JavaProxyThrowable: System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'SslStream'.
System.Net.Security.SslStream.get_Impl()
System.Net.Security.SslStream.get_Impl()(wrapper remoting-invoke-with-check)

Xamarin caused by: android.runtime.JavaProxyThrowable: System.NullReferenceException: Object reference not set to an instance of an object
System.Net.HttpWebRequest.get_ClientCertificates()
System.Net.HttpWebRequest.get_ClientCertificates()(wrapper remoting-invoke-with-check)

Xamarin caused by: android.runtime.JavaProxyThrowable: System.NullReferenceException: Object reference not set to an instance of an object
System.Net.HttpWebRequest.get_ServerCertValidationCallback()
System.Net.HttpWebRequest.get_ServerCertValidationCallback()(wrapper remoting-invoke-with-check)

Xamarin caused by: android.runtime.JavaProxyThrowable: System.NullReferenceException: Object reference not set to an instance of an object
Mono.Security.Protocol.Tls.TlsStream.ToArray()
Mono.Security.Protocol.Tls.TlsStream.ToArray()(wrapper remoting-invoke-with-check)

Xamarin caused by: android.runtime.JavaProxyThrowable: System.NullReferenceException: Object reference not set to an instance of an object
System.Collections.Generic.List<T>.Add(T item)

Xamarin caused by: android.runtime.JavaProxyThrowable: System.NullReferenceException: Object reference not set to an instance of an object
  at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].UnsafeOnCompleted (System.Action continuation) <0x9c1fa264 + 0x00014> in <162b154355a14010abd9ab37698d0a10>:0 
  at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[TResult].AwaitUnsafeOnCompleted[TAwaiter,TStateMachine] (TAwaiter& awaiter, TStateMachine& stateMachine) [0x0004c] in <162b154355a14010abd9ab37698d0a10>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_1 (System.Object state) <0x9c1f9ba0 + 0x00058> in <162b154355a14010abd9ab37698d0a10>:0 
  at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context (System.Object state) <0x9c151b64 + 0x0004f> in <162b154355a14010abd9ab37698d0a10>:0 
  at System.Threading.ExecutionContext.RunInternal (System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, System.Object state, System.Boolean preserveSyncCtx) <0x9c14ba74 + 0x001bb> in <162b154355a14010abd9ab37698d0a10>:0 
  at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem () <0x9c151afc + 0x0003b> in <162b154355a14010abd9ab37698d0a10>:0 
  at System.Threading.ThreadPoolWorkQueue.Dispatch () [0x00074] in <162b154355a14010abd9ab37698d0a10>:0 
  at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback () <0x9c15199c + 0x00007> in <162b154355a14010abd9ab37698d0a10>:0

Xamarin caused by: android.runtime.JavaProxyThrowable: System.NullReferenceException: Object reference not set to an instance of an object
System.Runtime.CompilerServices.TaskAwaiter.OnCompletedInternal(Task task, Action continuation, bool continueOnCapturedContext, bool flowExecutionContext)
System.Runtime.CompilerServices.TaskAwaiter<TResult>.UnsafeOnCompleted(Action continuation)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder<TResult>.AwaitUnsafeOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine)<162b154355a14010abd9ab37698d0a10>:0
System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(object state)
System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, object state, bool preserveSyncCtx)
System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
System.Threading.ThreadPoolWorkQueue.Dispatch()<162b154355a14010abd9ab37698d0a10>:0
System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()

An so on.

Version Information

Microsoft Visual Studio Professional 2017
Version 15.5.2
VisualStudio.15.Release/15.5.2+27130.2010
Microsoft .NET Framework
Version 4.7.02053

Installed Version: Professional

Xamarin 4.8.0.753 (6575bd113)
Visual Studio extension to enable development for Xamarin.iOS and Xamarin.Android.

Xamarin.Android SDK 8.1.0.25 (HEAD/d8c6e504f)
Xamarin.Android Reference Assemblies and MSBuild support.

Other

My naive assumptions is that this is a bug in GC, we'll definitely try SGEN in next release to check that.
Will try new GC bridge as well

RecyclerView.Adapter successor native peer members are disposed (only the android instance - Java.Lang.Object.Handle becomes 0x0) while adapter is still alive

Short Description of the issue

All members of my adapter class, that inherits the RecyclerView.Adapter, are being disposed in OnLoadFinished callback method
in my activity (responsible for displaying the loaded messages in RecyclerView) that inherits Android.Support.V4.App.LoaderManager.ILoaderCallbacks.

Short environment details:
Xamarin.Android Visual Studio project on Windows 10.

Steps to Reproduce

Run FindMe application (FindMe is the name of my application).
Press the gray square of the main activity (It will start the second activity, which displays a list with the SMS/MMS messages of the phone).
Press the back button of the phone to return back to the main activity.
Repeat step 2 and 3 several times (In most cases the bug will be reproduced within less than 10 times, but I reproduced it also from the 18 - 20 time).

Expected Behavior

I expect while the CMessagesAdapter (inherites RecyclerView.Adapter) is alive, all of its members to be also alive. Otherwise my application crashes when I try to call one of these members.

Actual Behavior

My successor class of RecyclerView.Adapter (CMessagesAdapter, see attached VS project) has a Java.Lang.String instance member, which Handle suddenly becomes 0x0.
Native peer objects of all of the members of theCMessagesAdapter suddenly are deleted (at least Handle becomes 0x0).
This happens in the OnLoadFinished callback method (my activity, CMessagingActivity, that has the RecyclerView, inherites Android.Support.V4.App.LoaderManager.ILoaderCallbacks).
After the loader loads the messages from the data base and returns back to the activity to display them, the the java instances of the adapter members are disposed.
This does not reproduce always, but very often. I managed to reproduced it at the 2nd and 3rd time, but also often at 6th and 9th time. I also reproduced it at 18th time,
so please check it at least 30 times to be sure that you will get to the problem.
When I say here "time" I mean: press the square button and wait the messages to load (OnLoadFinished is called). This is a single time. Then press the back button to return back and repeat the same steps one more time. This is a second time. So for example 9th time means that calling the OnLoadFInished for the 9th time.
I reproduced the problem both on release and debug.
I managed to reproduce it more easily (less steps) when I enabled gref and gc in the log
from the command line:
adb shell setprop debug.mono.log gref,gc

I managed to reproduces it only on my phone - LGE LG-H525n (this is LG G4c).
I couldn't reproduce this bug on an emulator.

Reproduced device info:

LGE LG-H525n (this is LG G4c)
Android: 6.0, API 23
Android security patch level: 2016-07-01
Kernel version: 3.10.49
Software Version: V20d-EUR-XX

My Environment:

See the MyEnvironment.txt file in the archive.

Version Information

Visual Studio Version Info file VisualStudioVersionInfo.txt is in the archive with the Visual Studio project and the rest files.

Log File

See the grefLog.txt file in the archive with the Visual Studio project and the rest files.

Source code and Visual Studio project

See the FindMe.7z

AndroidInstanceBugReportInBugzilla.zip

Early <AndroidAsset> caching results in differences w.r.t. other platforms, use case limits.

Steps to Reproduce

Extract the attached workspace, load the top-level solution.
For each of the four client projects (under Clients solution folder), build and run.
Observe the on-screen text (Android, iOS, UWP) or command line output (CLI).

BuildArtifacts.zip

Expected Behavior

In all cases, "This is actual content for asset A." is indicated.

Actual Behavior

For all of { CLI, iOS, UWP }, "This is actual content for asset A." is indicated.
For { Android }, "This is a placeholder for asset A." is indicated.

(Further commentary to follow.)

Version Information

Microsoft Visual Studio Community 2017
Version 15.5.2
VisualStudio.15.Release/15.5.2+27130.2010
Microsoft .NET Framework
Version 4.7.02556

Installed Version: Community

Visual Basic 2017 00369-60000-00001-AA028
Microsoft Visual Basic 2017

Visual C# 2017 00369-60000-00001-AA028
Microsoft Visual C# 2017

Visual C++ 2017 00369-60000-00001-AA028
Microsoft Visual C++ 2017

Visual F# 4.1 00369-60000-00001-AA028
Microsoft Visual F# 4.1