Bug 20812 - Inheriting from ArrayAdapter<__numeric_type-(int, long, short)__> fails to compile
Summary: Inheriting from ArrayAdapter<__numeric_type-(int, long, short)__> fails to co...
Alias: None
Product: Android
Classification: Xamarin
Component: Bindings ()
Version: 4.14.0
Hardware: PC Windows
: Normal normal
Target Milestone: ---
Assignee: Atsushi Eno
Depends on:
Reported: 2014-06-23 08:45 UTC by Dimitar Dobrev
Modified: 2014-06-25 05:53 UTC (History)
2 users (show)

Is this bug a regression?: ---
Last known good build:

The generated Java code that fails to compile (6.00 KB, text/x-java)
2014-06-23 08:45 UTC, Dimitar Dobrev

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Description Dimitar Dobrev 2014-06-23 08:45:14 UTC
Created attachment 7152 [details]
The generated Java code that fails to compile

private class DurationAdapter : ArrayAdapter<int>
            public DurationAdapter(Context context, int textViewResourceId, int[] objects) : base(context, textViewResourceId, objects)

fails with:

Error	43	 cannot find symbol
symbol  : constructor ArrayAdapter(android.content.Context,int,int[])
location: class android.widget.ArrayAdapter
		super (p0, p1, p2);
...\SettingsActivity_DurationAdapter.java	66	3

The whole SettingsActivity_DurationAdapter.java is attached.
Comment 1 Udham Singh 2014-06-23 11:44:10 UTC
I have checked this issue and  observed the same behavior mentioned in bug description. To reproduce this issue I have created a simple android application and implemented the code provided in bug description.

Screencast : http://www.screencast.com/t/UQW4GyWEkWO

Environment Info :

Windows 8.1
Xamarin.Android : 4.12.5 and 4.12.4
VS 2013
Comment 2 Dimitar Dobrev 2014-06-23 13:40:13 UTC
Can be worked around by replacing int[] with IList<int>.
Comment 3 Atsushi Eno 2014-06-25 05:53:34 UTC
So far it is due to Java Generics related limitation (last one at http://developer.xamarin.com/guides/android/advanced_topics/limitations/ )

Android.Widget.ArrayAdapter<T> is not really a true binding for android.widget.ArrayAdapter<T>. The true binding is Android.Widget.ArrayAdapter, and it basically maps T to Java.Lang.Object. ArrayAdapter<T> is just a workaround to bring some generic ease of use. By its nature, this T has to be either Java.Lang.Object (so that it can be mapped to java.lang.Object as ArrayAdapter's ACW [*1] is defined so) or some special things like collections. Primitive Java types cannot be directly converted to java.lang.Object, hence that Java compiler error is expected.)

Apart from using IList<int>, the more valid-looking way is to use Java.Lang.Integer instead of int.

[*1] http://developer.xamarin.com/guides/android/advanced_topics/java_integration_overview/android_callable_wrappers/

We may visit this issue later on, but that could bring breaking API changes and we may need to wait for not near future versions.