* [DevCom 788217](https://developercommunity.visualstudio.com/content/problem/788217/xamarin-android-resource-ids-mismatch-1.html):

A crash on startup could be encountered when the `MainLauncher` activity is implemented in a Xamarin.Android class library.

for (size_t i = 0; i < assemblies.get_length (); ++i) {

void SetTargetFrameworkAndManifest(XamarinAndroidApplicationProject proj, Builder builder)

{

string apiLevel;

proj.TargetFrameworkVersion = builder.LatestTargetFrameworkVersion (out apiLevel);

proj.AndroidManifest = $@"<?xml version=""1.0"" encoding=""utf-8""?>

}

SetTargetFrameworkAndManifest (proj, b);

[Test]

public void ClassLibraryMainLauncherRuns ()

{

if (!HasDevices) {

Assert.Ignore ("Test needs a device attached.");

return;

}

var path = Path.Combine ("temp", TestName);

var app = new XamarinAndroidApplicationProject {

ProjectName = "MyApp",

};

if (!CommercialBuildAvailable) {

var abis = new string [] { "armeabi-v7a", "x86" };

app.SetProperty (KnownProperties.AndroidSupportedAbis, string.Join (";", abis));

}

app.SetDefaultTargetDevice ();

var lib = new XamarinAndroidLibraryProject {

ProjectName = "MyLibrary"

};

lib.Sources.Add (new BuildItem.Source ("MainActivity.cs") {

TextContent = () => lib.ProcessSourceTemplate (app.DefaultMainActivity).Replace ("${JAVA_PACKAGENAME}", app.JavaPackageName),

});

lib.AndroidResources.Clear ();

foreach (var resource in app.AndroidResources) {

lib.AndroidResources.Add (resource);

}

var reference = $"..\\{lib.ProjectName}\\{lib.ProjectName}.csproj";

app.References.Add (new BuildItem.ProjectReference (reference, lib.ProjectName, lib.ProjectGuid));

// Remove the default MainActivity.cs & AndroidResources

app.AndroidResources.Clear ();

app.AndroidResources.Add (new AndroidItem.AndroidResource ("Resources\\layout\\foo.xml") {

TextContent = () => "<?xml version=\"1.0\" encoding=\"utf-8\" ?><LinearLayout xmlns:android=\"http://schemas.android.com/apk/res/android\" />"

});

app.Sources.Remove (app.GetItem ("MainActivity.cs"));

using (var libBuilder = CreateDllBuilder (Path.Combine (path, lib.ProjectName)))

using (var appBuilder = CreateApkBuilder (Path.Combine (path, app.ProjectName))) {

SetTargetFrameworkAndManifest (app, appBuilder);

Assert.IsTrue (libBuilder.Build (lib), "library build should have succeeded.");

Assert.True (appBuilder.Install (app), "app should have installed.");

ClearAdbLogcat ();

if (CommercialBuildAvailable)

Assert.True (appBuilder.RunTarget (app, "_Run"), "Project should have run.");

else

AdbStartActivity ($"{app.PackageName}/{app.JavaPackageName}.MainActivity");

Assert.True (WaitForActivityToStart (app.PackageName, "MainActivity",

Path.Combine (Root, appBuilder.ProjectDirectory, "logcat.log"), 30), "Activity should have started.");

}

}

SetTargetFrameworkAndManifest (proj, b);

SetTargetFrameworkAndManifest (proj, b);