Pixiview/Gallery.Android/Renderers/AppShellSection/AppShellBottomNavViewAppearanceTracker.cs

using Android.Content.Res;
using Android.Graphics.Drawables;
#if __ANDROID_29__
using AndroidX.Core.Widget;
using Google.Android.Material.BottomNavigation;
#else
using Android.Support.Design.Internal;
using Android.Support.Design.Widget;
#endif
using System;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;
using AColor = Android.Graphics.Color;
using R = Android.Resource;

namespace Gallery.Droid.Renderers.AppShellSection
{
    public class AppShellBottomNavViewAppearanceTracker : IShellBottomNavViewAppearanceTracker
    {
        [System.Diagnostics.CodeAnalysis.SuppressMessage("CodeQuality", "IDE0052:Remove unread private members", Justification = "<Pending>")]
        IShellContext _shellContext;
        ShellItem _shellItem;
        ColorStateList _defaultList;
        bool _disposed;
        ColorStateList _colorStateList;

        public AppShellBottomNavViewAppearanceTracker(IShellContext shellContext, ShellItem shellItem)
        {
            _shellItem = shellItem;
            _shellContext = shellContext;
        }

        public virtual void ResetAppearance(BottomNavigationView bottomView)
        {
            if (_defaultList != null)
            {
                bottomView.ItemTextColor = _defaultList;
                bottomView.ItemIconTintList = _defaultList;
            }

            SetBackgroundColor(bottomView, Color.White);
        }

        public virtual void SetAppearance(BottomNavigationView bottomView, IShellAppearanceElement appearance)
        {
            IShellAppearanceElement controller = appearance;
            var backgroundColor = controller.EffectiveTabBarBackgroundColor;
            var foregroundColor = controller.EffectiveTabBarForegroundColor;
            var disabledColor = controller.EffectiveTabBarDisabledColor;
            var unselectedColor = controller.EffectiveTabBarUnselectedColor; // currently unused
            var titleColor = controller.EffectiveTabBarTitleColor;

            if (_defaultList == null)
            {
#if __ANDROID_28__
                _defaultList = bottomView.ItemTextColor ?? bottomView.ItemIconTintList
                    ?? MakeColorStateList(titleColor.ToAndroid().ToArgb(), disabledColor.ToAndroid().ToArgb(), foregroundColor.ToAndroid().ToArgb());
#else
                _defaultList = bottomView.ItemTextColor ?? bottomView.ItemIconTintList;
#endif
            }

            _colorStateList = MakeColorStateList(titleColor, disabledColor, foregroundColor);
            bottomView.ItemTextColor = _colorStateList;
            bottomView.ItemIconTintList = _colorStateList;

            var menu = bottomView.Menu;
            if (menu != null && menu.HasVisibleItems && menu.Size() == 4)
            {
                var itemUser = menu.GetItem(0);
                itemUser.SetIcon(itemUser.IsChecked ?
                    Resource.Drawable.ic_user :
                    Resource.Drawable.ic_user_regular);
                var itemRecommend = menu.GetItem(1);
                itemRecommend.SetIcon(itemRecommend.IsChecked ?
                    Resource.Drawable.ic_sparkles :
                    Resource.Drawable.ic_sparkles_regular);
                var itemRank = menu.GetItem(2);
                itemRank.SetIcon(itemRank.IsChecked ?
                    Resource.Drawable.ic_rank :
                    Resource.Drawable.ic_rank_regular);
                var itemFavorite = menu.GetItem(3);
                itemFavorite.SetIcon(itemFavorite.IsChecked ?
                    Resource.Drawable.ic_bookmark :
                    Resource.Drawable.ic_bookmark_regular);
            }

            SetBackgroundColor(bottomView, backgroundColor);
        }

        protected virtual void SetBackgroundColor(BottomNavigationView bottomView, Color color)
        {
            var oldBackground = bottomView.Background;
            var colorDrawable = oldBackground as ColorDrawable;
            var colorChangeRevealDrawable = oldBackground as AppColorChangeRevealDrawable;
            AColor lastColor = colorChangeRevealDrawable?.EndColor ?? colorDrawable?.Color ?? Color.Default.ToAndroid();
            AColor newColor;

            if (color == Color.Default)
                newColor = Color.White.ToAndroid();
            else
                newColor = color.ToAndroid();

            if (!(bottomView.GetChildAt(0) is BottomNavigationMenuView menuView))
            {
                if (colorDrawable != null && lastColor == newColor)
                    return;

                if (lastColor != newColor || colorDrawable == null)
                {
                    bottomView.SetBackground(new ColorDrawable(newColor));
                }
            }
            else
            {
                if (colorChangeRevealDrawable != null && lastColor == newColor)
                    return;

                var index = ((IShellItemController)_shellItem).GetItems().IndexOf(_shellItem.CurrentItem);
                var menu = bottomView.Menu;
                index = Math.Min(index, menu.Size() - 1);

                var child = menuView.GetChildAt(index);
                if (child == null)
                    return;

                var touchPoint = new Android.Graphics.Point(child.Left + (child.Right - child.Left) / 2, child.Top + (child.Bottom - child.Top) / 2);

                bottomView.SetBackground(new AppColorChangeRevealDrawable(lastColor, newColor, touchPoint));
            }
        }

        ColorStateList MakeColorStateList(Color titleColor, Color disabledColor, Color unselectedColor)
        {
            var disabledInt = disabledColor.IsDefault ?
                _defaultList.GetColorForState(new[] { -R.Attribute.StateEnabled }, AColor.Gray) :
                disabledColor.ToAndroid().ToArgb();

            var checkedInt = titleColor.IsDefault ?
                _defaultList.GetColorForState(new[] { R.Attribute.StateChecked }, AColor.Black) :
                titleColor.ToAndroid().ToArgb();

            var defaultColor = unselectedColor.IsDefault ?
                _defaultList.DefaultColor :
                unselectedColor.ToAndroid().ToArgb();

            return MakeColorStateList(checkedInt, disabledInt, defaultColor);
        }

        ColorStateList MakeColorStateList(int titleColorInt, int disabledColorInt, int defaultColor)
        {
            var states = new int[][] {
                new int[] { -R.Attribute.StateEnabled },
                new int[] {R.Attribute.StateChecked },
                new int[] { }
            };

            var colors = new[] { disabledColorInt, titleColorInt, defaultColor };

            return new ColorStateList(states, colors);
        }

        #region IDisposable

        public void Dispose()
        {
            Dispose(true);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (_disposed)
                return;

            _disposed = true;

            if (disposing)
            {
                _defaultList?.Dispose();
                _colorStateList?.Dispose();

                _shellItem = null;
                _shellContext = null;
                _defaultList = null;
                _colorStateList = null;
            }
        }

        #endregion IDisposable
    }
}