Remove status bar underlay view in Android AppCompat (#892)

* Remove status bar underlay and handle status bar color with theme colors

* Fix layout gap when SoftInputMode is set to resize

* Restore linker settings

3 files changed, 16 insertions, 111 deletions

diff --git a/Xamarin.Forms.Platform.Android/AppCompat/FormsAppCompatActivity.cs b/Xamarin.Forms.Platform.Android/AppCompat/FormsAppCompatActivity.cs
index 8bba063b..e0bac30e 100644
--- a/Xamarin.Forms.Platform.Android/AppCompat/FormsAppCompatActivity.cs
+++ b/Xamarin.Forms.Platform.Android/AppCompat/FormsAppCompatActivity.cs
@@ -45,8 +45,6 @@ namespace Xamarin.Forms.Platform.Android
 		AndroidApplicationLifecycleState _previousState;
 
 		bool _renderersAdded, _isFullScreen;
-		int _statusBarHeight = -1;
-		global::Android.Views.View _statusBarUnderlay;
 
 		// Override this if you want to handle the default Android behavior of restoring fragments on an application restart
 		protected virtual bool AllowFragmentRestore => false;
@@ -105,7 +103,10 @@ namespace Xamarin.Forms.Platform.Android
 
 		public void SetStatusBarColor(AColor color)
 		{
-			_statusBarUnderlay.SetBackgroundColor(color);
+			if (Forms.IsLollipopOrNewer)
+			{
+				Window.SetStatusBarColor(color);
+			}
 		}
 
 		protected void LoadApplication(Application application)
@@ -171,7 +172,7 @@ namespace Xamarin.Forms.Platform.Android
 			}
 			else
 				bar = new AToolbar(this);
-
+			
 			SetSupportActionBar(bar);
 
 			_layout = new ARelativeLayout(BaseContext);
@@ -184,7 +185,11 @@ namespace Xamarin.Forms.Platform.Android
 
 			OnStateChanged();
 
-			AddStatusBarUnderlay();
+			if (Forms.IsLollipopOrNewer)
+			{
+				// Allow for the status bar color to be changed
+				Window.AddFlags(WindowManagerFlags.DrawsSystemBarBackgrounds);
+			}
 		}
 
 		protected override void OnDestroy()
@@ -280,45 +285,6 @@ namespace Xamarin.Forms.Platform.Android
 			OnStateChanged();
 		}
 
-		internal int GetStatusBarHeight()
-		{
-			if (_statusBarHeight >= 0)
-				return _statusBarHeight;
-
-			var result = 0;
-			int resourceId = Resources.GetIdentifier("status_bar_height", "dimen", "android");
-			if (resourceId > 0)
-				result = Resources.GetDimensionPixelSize(resourceId);
-			return _statusBarHeight = result;
-		}
-
-		void AddStatusBarUnderlay()
-		{
-			_statusBarUnderlay = new global::Android.Views.View(this);
-
-			var layoutParameters = new ARelativeLayout.LayoutParams(ViewGroup.LayoutParams.MatchParent, GetStatusBarHeight()) { AlignWithParent = true };
-			layoutParameters.AddRule(LayoutRules.AlignTop);
-			_statusBarUnderlay.LayoutParameters = layoutParameters;
-			_layout.AddView(_statusBarUnderlay);
-
-			if (Forms.IsLollipopOrNewer)
-			{
-				Window.AddFlags(WindowManagerFlags.DrawsSystemBarBackgrounds);
-				Window.SetStatusBarColor(AColor.Transparent);
-
-				int primaryColorDark = GetColorPrimaryDark();
-
-				if (primaryColorDark != 0)
-				{
-					int r = AColor.GetRedComponent(primaryColorDark);
-					int g = AColor.GetGreenComponent(primaryColorDark);
-					int b = AColor.GetBlueComponent(primaryColorDark);
-					int a = AColor.GetAlphaComponent(primaryColorDark);
-					SetStatusBarColor(AColor.Argb(a, r, g, b));
-				}
-			}
-		}
-
 		void AppOnPropertyChanged(object sender, PropertyChangedEventArgs args)
 		{
 			if (args.PropertyName == "MainPage")
@@ -338,32 +304,6 @@ namespace Xamarin.Forms.Platform.Android
 			_application?.SendOnAppLinkRequestReceived(link);
 		}
 
-		int GetColorPrimaryDark()
-		{
-			FormsAppCompatActivity context = this;
-			int id = global::Android.Resource.Attribute.ColorPrimaryDark;
-			using (var value = new TypedValue())
-			{
-				try
-				{
-					Resources.Theme theme = context.Theme;
-					if (theme != null && theme.ResolveAttribute(id, value, true))
-					{
-						if (value.Type >= DataType.FirstInt && value.Type <= DataType.LastInt)
-							return value.Data;
-						if (value.Type == DataType.String)
-							return ContextCompat.GetColor(context, value.ResourceId);
-					}
-				}
-				catch (Exception ex)
-				{
-					Internals.Log.Warning("Xamarin.Forms.Platform.Android.FormsAppCompatActivity", "Error retrieving color resource: {0}", ex);
-				}
-
-				return -1;
-			}
-		}
-
 		void InternalSetPage(Page page)
 		{
 			if (!Forms.IsInitialized)
@@ -477,7 +417,6 @@ namespace Xamarin.Forms.Platform.Android
 			}
 
 			Window.SetSoftInputMode(adjust);
-			SetStatusBarVisibility(adjust);
 		}
 
 		public override void OnWindowAttributesChanged(WindowManagerLayoutParams @params)
@@ -512,21 +451,6 @@ namespace Xamarin.Forms.Platform.Android
 			AppCompat.Platform.LayoutRootPage(this, Xamarin.Forms.Application.Current.MainPage, width, height);
 		}
 
-		void SetStatusBarVisibility(SoftInput mode)
-		{
-			if (!Forms.IsLollipopOrNewer)
-				return;
-
-			if (mode == SoftInput.AdjustResize)
-			{
-				Window.DecorView.SystemUiVisibility = (StatusBarVisibility)(SystemUiFlags.Immersive);
-			}
-			else
-				Window.DecorView.SystemUiVisibility = (StatusBarVisibility)(SystemUiFlags.LayoutFullscreen | SystemUiFlags.LayoutStable);
-
-			_layout?.Invalidate();
-		}
-
 		void UpdateProgressBarVisibility(bool isBusy)
 		{
 			if (!Forms.SupportsProgress)
diff --git a/Xamarin.Forms.Platform.Android/AppCompat/MasterDetailPageRenderer.cs b/Xamarin.Forms.Platform.Android/AppCompat/MasterDetailPageRenderer.cs
index a1c4092e..5104800d 100644
--- a/Xamarin.Forms.Platform.Android/AppCompat/MasterDetailPageRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/AppCompat/MasterDetailPageRenderer.cs
@@ -113,23 +113,17 @@ namespace Xamarin.Forms.Platform.Android.AppCompat
 				oldElement.Disappearing -= MasterDetailPageDisappearing;
 			}
 
-			var statusBarHeight = 0;
-			if (Forms.IsLollipopOrNewer)
-				statusBarHeight = ((FormsAppCompatActivity)Context).GetStatusBarHeight();
-
 			if (newElement != null)
 			{
 				if (_detailLayout == null)
 				{
 					_detailLayout = new MasterDetailContainer(newElement, false, Context)
 					{
-						TopPadding = HasAncestorNavigationPage(Element) ? 0 : statusBarHeight,
 						LayoutParameters = new LayoutParams(ViewGroup.LayoutParams.WrapContent, ViewGroup.LayoutParams.WrapContent)
 					};
 
 					_masterLayout = new MasterDetailContainer(newElement, true, Context)
 					{
-						TopPadding = ((IMasterDetailPageController)newElement).ShouldShowSplitMode ? statusBarHeight : 0,
 						LayoutParameters = new LayoutParams(ViewGroup.LayoutParams.WrapContent, ViewGroup.LayoutParams.WrapContent) { Gravity = (int)GravityFlags.Start }
 					};
 
diff --git a/Xamarin.Forms.Platform.Android/AppCompat/Platform.cs b/Xamarin.Forms.Platform.Android/AppCompat/Platform.cs
index 872bac77..be54ea0a 100644
--- a/Xamarin.Forms.Platform.Android/AppCompat/Platform.cs
+++ b/Xamarin.Forms.Platform.Android/AppCompat/Platform.cs
@@ -8,7 +8,6 @@ using Android.Views;
 using Android.Views.Animations;
 using ARelativeLayout = Android.Widget.RelativeLayout;
 using Xamarin.Forms.Internals;
-using Debug = System.Diagnostics.Debug;
 
 namespace Xamarin.Forms.Platform.Android.AppCompat
 {
@@ -196,7 +195,9 @@ namespace Xamarin.Forms.Platform.Android.AppCompat
 		void IPlatformLayout.OnLayout(bool changed, int l, int t, int r, int b)
 		{
 			if (changed)
+			{
 				LayoutRootPage((FormsAppCompatActivity)_context, Page, r - l, b - t);
+			}
 
 			Android.Platform.GetRenderer(Page).UpdateLayout();
 
@@ -286,15 +287,7 @@ namespace Xamarin.Forms.Platform.Android.AppCompat
 
 		internal static void LayoutRootPage(FormsAppCompatActivity activity, Page page, int width, int height)
 		{
-			int statusBarHeight = Forms.IsLollipopOrNewer ? activity.GetStatusBarHeight() : 0;
-			statusBarHeight = activity.Window.Attributes.Flags.HasFlag(WindowManagerFlags.Fullscreen) || Forms.TitleBarVisibility == AndroidTitleBarVisibility.Never ? 0 : statusBarHeight;
-
-			if (page is MasterDetailPage)
-				page.Layout(new Rectangle(0, 0, activity.FromPixels(width), activity.FromPixels(height)));
-			else
-			{
-				page.Layout(new Rectangle(0, activity.FromPixels(statusBarHeight), activity.FromPixels(width), activity.FromPixels(height - statusBarHeight)));
-			}
+			page.Layout(new Rectangle(0, 0, activity.FromPixels(width), activity.FromPixels(height)));
 		}
 
 		Task PresentModal(Page modal, bool animated)
@@ -381,18 +374,12 @@ namespace Xamarin.Forms.Platform.Android.AppCompat
 
 			protected override void OnLayout(bool changed, int l, int t, int r, int b)
 			{
-				var activity = (FormsAppCompatActivity)Context;
-				int statusBarHeight = Forms.IsLollipopOrNewer ? activity.GetStatusBarHeight() : 0;
 				if (changed)
 				{
-					if (_modal is MasterDetailPage)
-						_modal.Layout(new Rectangle(0, 0, activity.FromPixels(r - l), activity.FromPixels(b - t)));
-					else
-					{
-						_modal.Layout(new Rectangle(0, activity.FromPixels(statusBarHeight), activity.FromPixels(r - l), activity.FromPixels(b - t - statusBarHeight)));
-					}
+					var activity = (FormsAppCompatActivity)Context;
 
-					_backgroundView.Layout(0, statusBarHeight, r - l, b - t);
+					_modal.Layout(new Rectangle(0, 0, activity.FromPixels(r - l), activity.FromPixels(b - t)));
+					_backgroundView.Layout(0, 0, r - l, b - t);
 				}
 
 				_renderer.UpdateLayout();