Fix issue 504 #512
Fix issue 504 #512
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/azp run |
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Do we know why the Does this need to be |
From what I saw - generics. IIRC something in the form
No. It was parameter type erasure. |
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I don't think I understand how this will solve the reported issue. The user wants to override this method: public Intent createIntent(Context context, String input) { ... }The method this PR adds is not Additionally, even making this method Given that the existing method does not appear to work, I think we should look at fixing it instead of adding this additional overload. |
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I think the reported Java error is because the type was modified using Using |
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Testing looks good, so this is fine to commit now:
dotnet/java-interop#967 (comment)
Fixes: #967 Context: dotnet/android-libraries#504 Context: #424 Context: #586 Context: #918 Java generics continues to be a "difficulty" in creating bindings. Consider [`ActivityResultContracts.RequestPermission`][0]: // Java public abstract /* partial */ class ActivityResultContract<I, O> { public abstract Intent createIntent(Context context, I input); } public /* partial */ class /* ActivityResultContracts. */ RequestPermission extends ActivityResultContract<String, Boolean> { @OverRide public Intent createIntent(Context context, String input) {…} } The JNI Signature for `ActivityResultContracts.RequestPermission.createIntent()` is `(Landroid/content/Context;Ljava/lang/String;)Landroid/content/Intent;`, i.e. `class-parse` & `generator` believe that the `input` parameter is of type `String`, which we bind by default as `string`. Thus: // C# public abstract partial class ActivityResultContract { public abstract Intent CreateIntent (Context? context, Java.Lang.Object? input) => … } public partial class /* ActivityResultContracts. */ RequestPermission { public override Intent CreateIntent (Context? context, string? input) => … } This fails to compile with a [CS0115][1]: 'RequestPermission.CreateIntent(Context?, string?)': no suitable method found to override as the `input` parameter of `RequestPermission.CreateIntent()` changes from `Java.Lang.Object?` to `string?`. We can attempt to address this via Metadata: <attr path="/api/package[@name='androidx.activity.result.contract']/class[@name='ActivityResultContracts.RequestPermission']/method[@name='createIntent' and count(parameter)=2 and parameter[1][@type='android.content.Context'] and parameter[2][@type='java.lang.String']]" name="managedType" >Java.Lang.Object</attr> This fixes one error, as `generator` now emits: public partial class /* ActivityResultContracts. */ RequestPermission { [Register ("createIntent", "(Landroid/content/Context;Ljava/lang/String;)Landroid/content/Intent;", "")] public override unsafe global::Android.Content.Intent CreateIntent (global::Android.Content.Context context, global::Java.Lang.Object input) { const string __id = "createIntent.(Landroid/content/Context;Ljava/lang/String;)Landroid/content/Intent;"; IntPtr native_input = JNIEnv.NewString (input); try { JniArgumentValue* __args = stackalloc JniArgumentValue [2]; __args [0] = new JniArgumentValue ((context == null) ? IntPtr.Zero : ((global::Java.Lang.Object) context).Handle); __args [1] = new JniArgumentValue (native_input); var __rm = _members.InstanceMethods.InvokeAbstractObjectMethod (__id, this, __args); return global::Java.Lang.Object.GetObject<global::Android.Content.Intent> (__rm.Handle, JniHandleOwnership.TransferLocalRef); } finally { JNIEnv.DeleteLocalRef (native_input); global::System.GC.KeepAlive (context); global::System.GC.KeepAlive (input); } } } The `override` method declaration is correct. However, this introduces a [CS1503][2] error: IntPtr native_input = JNIEnv.NewString (input); // Error CS1503 Argument 1: cannot convert from 'Java.Lang.Object' to 'string?' The workaround is to remove `createIntent()` ~entirely, and manually bind it, as done in dotnet/android-libraries#512. Fix this issue by always emitting a cast to `(string)` as part of the `JNIEnv.NewString()` invocation, instead emitting: IntPtr native_input = JNIEnv.NewString ((string?) input); This works because `Java.Lang.Object` defines an [explicit conversion to `string?`][3], and if a `Java.Lang.String` instance is provided to the `input` parameter, it's equivalent to calling `.ToString()`. This fix allows the original suggested Metadata solution to work. [0]: https://developer.android.com/reference/androidx/activity/result/contract/ActivityResultContracts.RequestPermission [1]: https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/compiler-messages/cs0115 [2]: https://docs.microsoft.com/en-us/dotnet/csharp/misc/cs1503 [3]: https://github.com/xamarin/xamarin-android/blob/a58d4e9706455227eabb6e5b5103b25da716688b/src/Mono.Android/Java.Lang/Object.cs#L434-L439
Does this change any of the generated binding API's?
Yes. Adds overloaded
CreateIntentmethod withstringparameter.Fix for #504
Describe your contribution
CreateIntent parameter fix
remove-node