Pixiview/Pixiview.iOS/Renderers/AppShellRenderer.cs

using System.Diagnostics.CodeAnalysis;
using System.Threading.Tasks;
using Pixiview.iOS.Renderers;
using Pixiview.iOS.Renderers.AppShellSection;
using Pixiview.Utils;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

[assembly: ExportRenderer(typeof(Shell), typeof(AppShellRenderer))]
namespace Pixiview.iOS.Renderers
{
    public class AppShellRenderer : ShellRenderer
    {
        public override bool PrefersHomeIndicatorAutoHidden => Screen.GetHomeIndicatorAutoHidden(Element);

        protected override IShellSectionRenderer CreateShellSectionRenderer(ShellSection shellSection)
        {
            var renderer = new AppShellSectionRenderer(this);
            if (renderer is ShellSectionRenderer sr && Element is AppShell shell)
            {
                shell.SetNavigationBarHeight(
                    sr.NavigationBar.Frame.Height,
                    UIApplication.SharedApplication.StatusBarFrame.Height);
            }
            return renderer;
        }

        [SuppressMessage("Code Notifications", "XI0002:Notifies you from using newer Apple APIs when targeting an older OS version", Justification = "<Pending>")]
        protected override IShellItemRenderer CreateShellItemRenderer(ShellItem item)
        {
            var renderer = base.CreateShellItemRenderer(item);
            if (UIDevice.CurrentDevice.CheckSystemVersion(13, 0))
            {
                if (renderer.ViewController is UITabBarController controller)
                {
                    var tabBar = controller.TabBar;
                    tabBar.TintColor = UIColor.LabelColor;
                    tabBar.UnselectedItemTintColor = UIColor.SecondaryLabelColor;
                }
            }
            return renderer;
        }

        protected override IShellItemTransition CreateShellItemTransition()
        {
            return new AppShellItemTransition();
        }

        protected override IShellTabBarAppearanceTracker CreateTabBarAppearanceTracker()
        {
            return new AppShellTabBarAppearanceTracker();
        }
    }

    public class AppShellItemTransition : IShellItemTransition
    {
        [SuppressMessage("Code Notifications", "XI0001:Notifies you with advices on how to use Apple APIs", Justification = "<Pending>")]
        public Task Transition(IShellItemRenderer oldRenderer, IShellItemRenderer newRenderer)
        {
            var task = new TaskCompletionSource<bool>();
            var oldView = oldRenderer.ViewController.View;
            var newView = newRenderer.ViewController.View;
            newView.Alpha = 0;

            newView.Superview.InsertSubviewAbove(newView, oldView);

            UIView.Animate(0.2, 0, UIViewAnimationOptions.BeginFromCurrentState, () => newView.Alpha = 1, () => task.TrySetResult(true));

            return task.Task;
        }
    }

    public class AppShellTabBarAppearanceTracker : IShellTabBarAppearanceTracker
    {
        UIColor _defaultBarTint;
        UIColor _defaultTint;
        UIColor _defaultUnselectedTint;

        public void Dispose()
        {
        }

        public void ResetAppearance(UITabBarController controller)
        {
            if (_defaultTint == null)
                return;

            var tabBar = controller.TabBar;
            tabBar.BarTintColor = _defaultBarTint;
            tabBar.TintColor = _defaultTint;
            tabBar.UnselectedItemTintColor = _defaultUnselectedTint;
        }

        public void SetAppearance(UITabBarController controller, ShellAppearance appearance)
        {
            IShellAppearanceElement appearanceElement = appearance;
            //var backgroundColor = appearanceElement.EffectiveTabBarBackgroundColor;
            var unselectedColor = appearanceElement.EffectiveTabBarUnselectedColor;
            var titleColor = appearanceElement.EffectiveTabBarTitleColor;

            var tabBar = controller.TabBar;
            //bool operatingSystemSupportsUnselectedTint = Forms.IsiOS10OrNewer;

            if (_defaultTint == null)
            {
                _defaultBarTint = tabBar.BarTintColor;
                _defaultTint = tabBar.TintColor;

                //if (operatingSystemSupportsUnselectedTint)
                {
                    _defaultUnselectedTint = tabBar.UnselectedItemTintColor;
                }
            }

            //if (!backgroundColor.IsDefault)
            //    tabBar.BarTintColor = backgroundColor.ToUIColor();
            if (!UIDevice.CurrentDevice.CheckSystemVersion(13, 0))
            {
                if (!titleColor.IsDefault)
                    tabBar.TintColor = titleColor.ToUIColor();

                //if (operatingSystemSupportsUnselectedTint)
                {
                    if (!unselectedColor.IsDefault)
                        tabBar.UnselectedItemTintColor = unselectedColor.ToUIColor();
                }
            }
        }

        public void UpdateLayout(UITabBarController controller)
        {
        }
    }

    public class AppShellSectionRenderer : ShellSectionRenderer
    {
        public AppShellSectionRenderer(IShellContext context) : base(context)
        {
        }

        protected override IShellSectionRootRenderer CreateShellSectionRootRenderer(ShellSection shellSection, IShellContext shellContext)
        {
            return new AppShellSectionRootRenderer(shellSection, shellContext);
        }
    }

    public class AppShellSectionRootRenderer : ShellSectionRootRenderer
    {
        public AppShellSectionRootRenderer(ShellSection shellSection, IShellContext shellContext) : base(shellSection, shellContext)
        {
        }

        protected override IShellSectionRootHeader CreateShellSectionRootHeader(IShellContext shellContext)
        {
            return new AppShellSectionRootHeader(shellContext);
        }
    }
}