Set $(SupportedOSPlatformVersion)=24 in Android template
#9517
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Fixes: #9517 Context: #9527 Context: dotnet/java-interop@1f27ab5 Context: dotnet/android-libraries#767 Context: dotnet/android-libraries#767 (comment) [Desugaring][0] is an Android SDK build step which rewrites Java bytecode so that some Java 8+ language constructs can be used on older Android versions, containing a Dalvik VM that doesn't natively support those constructs. The primary examples are interface static methods and interface default methods, which *moves* methods from the declaring type to a *different* `$-CC`-suffixed type. For example, consider [`ImageAnalysis.Analyzer.getDefaultTargetResolution()`][1], which is an interface default method: // Java /* partial */ class ImageAnalysis { /* partial */ interface Analyzer { default Size getDefaultTargetResolution() {…} } } Our bindings for `androidx.camera.core` expect the `getDefaultTargetResolution()` method to be on `Analyzer`: // C# [Register("androidx/camera/core/ImageAnalysis$Analyzer", "", "AndroidX.Camera.Core.ImageAnalysis/IAnalyzerInvoker")] public partial interface IAnalyzer : IJavaObject, IDisposable, IJavaPeerable { unsafe Size? DefaultTargetResolution { [Register("getDefaultTargetResolution", "()Landroid/util/Size;", "GetGetDefaultTargetResolutionHandler:AndroidX.Camera.Core.ImageAnalysis/IAnalyzer, Xamarin.AndroidX.Camera.Core")] get { return Java.Lang.Object.GetObject<Size>(_members.InstanceMethods.InvokeVirtualObjectMethod("getDefaultTargetResolution.()Landroid/util/Size;", this, null).Handle, JniHandleOwnership.TransferLocalRef); } } } When desugaring is used, the `Analyzer` interface is changed, moving the default interface method body to a separate type: /* partial */ interface Analyzer { Size getDefaultTargetResolution(); // interface declaration } /* partial */ class Analyzer$-CC { Size getDefaultTargetResolution() {…} // default implementation } The movement of methods across types breaks our JNI-based bindings, which don't have easy support for such movements. The movement of `getDefaultTargetResolution()` causes C# apps attempting to invoke the `ImageAnalysis.IAnalyzer.DefaultTargetResolution` property *crash*: JNI DETECTED ERROR IN APPLICATION: JNI CallObjectMethodA called with pending exception java.lang.AbstractMethodError: abstract method "android.util.Size androidx.camera.core.ImageAnalysis$Analyzer.getDefaultTargetResolution()" The workaround is to *not desugar* the app, which can be done by setting `$(SupportedOSPlatformVersion)`=24, which sets the minimum supported Android version to Android 7.0, released 2016-Aug-22. We could fix this, but the fix is only needed for apps which need to run on Android 6.0 API-23 and earlier devices. As these devices are so old, we'd rather focus on more important issues. Attempt to improve things by updating the `dotnet new android` template in .NET 10 so that the default `$(SupportedOSPlatformVersion)` value is 24, up from 21. This will avoid the entire desugaring problem for new apps (until they set `$(SupportedOSPlatformVersion)` to 23 or lower…). Note that Android 5.0 / API-21 will still be the supported minimum for those that need it, however this will keep most users who do not need to support devices that old from having desugaring issues. [0]: https://developer.android.com/studio/write/java8-support [1]: https://developer.android.com/reference/androidx/camera/core/ImageAnalysis.Analyzer#getDefaultTargetResolution()
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Context: dotnet/android-libraries#767
Context: dotnet/android-libraries#767 (comment)
For .NET 10, we should update the
dotnet new androidtemplate so that$(SupportedOSPlatformVersion)is 24, bumping from the current default of 21.The reason for this is that "desugaring" "moves" Java methods to locations that we don't expect, which can result in
AbstractMethodErrors at runtime. Setting the minimum SDK version to >= 24 avoids this desugaring step, preventing the Java methods from being moved in a manner we don't expect, and thus avoiding theAbstractMethodError.Note that 21 will still be the supported minimum for those that need it, however this will keep most users who do not need to support devices that old from having desugaring issues.
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