AppCompat-v22 Tinting for MvvmCross

MvxAppCompatSpinner.cs

/// <summary>
/// Tint-aware version of MvxSpinner so that it's styled properly
/// with AppCompat V21
/// </summary>
public class MvxAppCompatSpinner : MvxSpinner, ITintableBackgroundView
{
    private static readonly int[] TintAttrs =
    {
        Android.Resource.Attribute.Background,
        Android.Resource.Attribute.PopupBackground
    };

    private TintInfo _backgroundTint;

    public MvxAppCompatSpinner(Context context)
        : this(context, null) {}

    public MvxAppCompatSpinner(Context context, IAttributeSet attributes)
        : base(context, attributes)
    {
        if (TintManager.ShouldBeUsed)
        {
            TintTypedArray a = TintTypedArray.ObtainStyledAttributes(context, attributes,
                TintAttrs, Android.Resource.Attribute.SpinnerStyle, 0);
            if (a.HasValue(0))
            {
                ColorStateList tint = a.TintManager.GetTintList(a.GetResourceId(0, -1));
                if (tint != null)
                {
                    SupportBackgroundTintList = tint;
                }
            }
            if (a.HasValue(1))
            {
                Drawable popupBackground = a.GetDrawable(1);
                if ((int)Build.VERSION.SdkInt >= 16)
                {
                    SetPopupBackgroundDrawable(popupBackground);
                }
                else if ((int)Build.VERSION.SdkInt >= 11)
                {
                    SetPopupBackgroundDrawableV11(this, popupBackground);
                }
            }
            a.Recycle();
        }
    }

    [TargetApi(Value = (int)BuildVersionCodes.Honeycomb)]
    private static void SetPopupBackgroundDrawableV11(Spinner view, Drawable background)
    {
        try
        {
            Field popupField = Class.FromType(typeof(Spinner)).GetDeclaredField("mPopup");
            popupField.Accessible = true;

            Object popup = popupField.Get(view);

            if (popup is ListPopupWindow)
            {
                ((ListPopupWindow)popup).SetBackgroundDrawable(background);
            }
        }
        catch (NoSuchFieldException e)
        {
            e.PrintStackTrace();
        }
        catch (IllegalAccessException e)
        {
            e.PrintStackTrace();
        }
    }

    public ColorStateList SupportBackgroundTintList
    {
        get { return _backgroundTint != null ? _backgroundTint.MTintList : null; }
        set
        {
            if (_backgroundTint == null)
            {
                _backgroundTint = new TintInfo();
            }
            _backgroundTint.MTintList = value;
            _backgroundTint.MHasTintList = true;

            ApplySupportBackgroundTint();
        }
    }


    public PorterDuff.Mode SupportBackgroundTintMode
    {
        get { return _backgroundTint != null ? _backgroundTint.MTintMode : null; }
        set
        {
            if (_backgroundTint == null)
            {
                _backgroundTint = new TintInfo();
            }
            _backgroundTint.MTintMode = value;
            _backgroundTint.MHasTintMode = true;

            ApplySupportBackgroundTint();
        }
    }

    protected override void DrawableStateChanged()
    {
        base.DrawableStateChanged();
        ApplySupportBackgroundTint();
    }

    private void ApplySupportBackgroundTint()
    {
        if (Background != null && _backgroundTint != null)
            TintManager.TintViewBackground(this, _backgroundTint);
    }
}

Setup.cs

public class Setup : MvxAndroidSetup
{
    public Setup(Context applicationContext) : base(applicationContext)
    {
    }

    protected override IMvxApplication CreateApp()
    {
        return new App();
    }

    protected override IMvxTrace CreateDebugTrace()
    {
        return new DebugTrace();
    }

    protected override IList<Assembly> AndroidViewAssemblies
    {
        get
        {
            var toReturn = base.AndroidViewAssemblies;

            // Add assemblies with other views we use.  When the XML is inflated
            // MvvmCross knows about the types and won't compain about them.  This
            // speeds up inflation noticeably.
            toReturn.Add(typeof(DrawerLayout).Assembly);
            toReturn.Add(typeof(SwitchCompat).Assembly);

            return toReturn;
        }
    }

    public class AppCompatViewFactory : MvxAndroidViewFactory
    {
        public override View CreateView(View parent, string name, Context context, IAttributeSet attrs)
        {
            if (Build.VERSION.SdkInt < BuildVersionCodes.Lollipop)
            {
                // If we're running pre-L, we need to 'inject' our tint aware Views in place of the
                // standard framework versions
                switch (name)
                {
                    case "EditText":
                            return new AppCompatEditText(context, attrs);
                    case "MvxSpinner": // Use our own tint-aware version of MvxSpinner
                        return new MvxAppCompatSpinner(context, attrs);
                    case "Spinner":
                        return new AppCompatSpinner(context, attrs);
                    case "CheckBox":
                        return new AppCompatCheckBox(context, attrs);
                    case "RadioButton":
                        return new AppCompatRadioButton(context, attrs);
                    case "CheckedTextView":
                        return new AppCompatCheckedTextView(context, attrs);
                    case "AutoCompleteTextView":
                        return new AppCompatAutoCompleteTextView(context, attrs);
                    case "MultiAutoCompleteTextView":
                        return new AppCompatMultiAutoCompleteTextView(context, attrs);
                    case "RatingBar":
                        return new AppCompatRatingBar(context, attrs);
                    case "Button":
                        return new AppCompatButton(context, attrs);
                }
            }
            return base.CreateView(parent, name, context, attrs);
        }
    }

    public class BindingBuilder : MvxAndroidBindingBuilder
    {
        protected override IMvxAndroidViewFactory CreateAndroidViewFactory()
        {
            return new AppCompatViewFactory();
        }
    }

    protected override MvxAndroidBindingBuilder CreateBindingBuilder()
    {
        return new BindingBuilder();
    }
}

Alternatively one can discriminate on the Context. This version is more forward compatible: for instance theme inheritance with v22.1 will work

private class AppCompat21ViewFactory : MvxAndroidViewFactory
{
            private static AppCompatDelegate GetDelegate(Context context)
            {
                // Special case this for when you know you have an AppCompatDelegate
                AppCompatActivity activity = context as AppCompatActivity;
                if (activity != null)
                {
                    return activity.Delegate;
                }

                return null;
            }

            public override View CreateView(View parent, string name, Context context, IAttributeSet attrs)
            {
                var @delegate = GetDelegate(context);
                if (@delegate != null)
                {
                    var view = @delegate.CreateView(parent, name, context, attrs);
                    if (view != null)
                        return view;

                    if (name == "MvxSpinner")
                    {
                        return new MvxAppCompatSpinner(context, attrs);
                    }
                }

                return base.CreateView(parent, name, context, attrs);
            }
        }