adjust UI

Gallery.iOS/Renderers/AppShellRenderer.cs

@@ -0,0 +1,93 @@
+using System.Diagnostics.CodeAnalysis;
+using System.Threading.Tasks;
+using Gallery.iOS.Renderers;
+using Gallery.iOS.Renderers.AppShellSection;
+using Gallery.Services;
+using UIKit;
+using Xamarin.Forms;
+using Xamarin.Forms.Platform.iOS;
+
+[assembly: ExportRenderer(typeof(Shell), typeof(AppShellRenderer))]
+namespace Gallery.iOS.Renderers
+{
+    public class AppShellRenderer : ShellRenderer
+    {
+
+        public override bool PrefersHomeIndicatorAutoHidden => Screen.GetHomeIndicatorAutoHidden(Element);
+
+        protected override IShellSectionRenderer CreateShellSectionRenderer(ShellSection shellSection)
+        {
+            var renderer = base.CreateShellSectionRenderer(shellSection);   // new AppShellSectionRenderer(this);
+            if (renderer is ShellSectionRenderer sr && Element is AppShell shell)
+            {
+                shell.SetNavigationBarHeight(sr.NavigationBar.Frame.Height);
+                shell.SetStatusBarHeight(
+                    sr.NavigationBar.Frame.Height,
+                    UIApplication.SharedApplication.StatusBarFrame.Height);
+            }
+            return renderer;
+        }
+
+        protected override IShellItemTransition CreateShellItemTransition()
+        {
+            return new AppShellItemTransition();
+        }
+
+        protected override IShellTabBarAppearanceTracker CreateTabBarAppearanceTracker()
+        {
+            return new AppShellTabBarAppearanceTracker();
+        }
+
+        protected override IShellNavBarAppearanceTracker CreateNavBarAppearanceTracker()
+        {
+            return new AppShellNavBarAppearanceTracker();
+        }
+
+        protected override void UpdateBackgroundColor()
+        {
+            NativeView.BackgroundColor = Color.Transparent.ToUIColor();
+        }
+    }
+
+    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 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);
+        }
+    }
+}