[mac] Manually handle disclosure arrows

This is largely required to get control over the left most column for
coloring and icon use.

Xamarin.PropertyEditing.Mac/Controls/EditorContainer.cs

@@ -43,6 +43,34 @@ namespace Xamarin.PropertyEditing.Mac
 			set { this.label.StringValue = value; }
 		}
 
+		public NSView LeftEdgeView
+		{
+			get { return this.leftEdgeView; }
+			set
+			{
+				if (this.leftEdgeView != null) {
+					this.leftEdgeView.RemoveFromSuperview ();
+					RemoveConstraints (new[] { this.leftEdgeLeftConstraint, this.leftEdgeVCenterConstraint });
+					this.leftEdgeLeftConstraint.Dispose ();
+					this.leftEdgeLeftConstraint = null;
+					this.leftEdgeVCenterConstraint.Dispose ();
+					this.leftEdgeVCenterConstraint = null;
+				}
+
+				this.leftEdgeView = value;
+
+				if (value != null) {
+					AddSubview (value);
+
+					value.TranslatesAutoresizingMaskIntoConstraints = false;
+					this.leftEdgeLeftConstraint = NSLayoutConstraint.Create (this.leftEdgeView, NSLayoutAttribute.Left, NSLayoutRelation.Equal, this, NSLayoutAttribute.Left, 1, 4);
+					this.leftEdgeVCenterConstraint = NSLayoutConstraint.Create (this.leftEdgeView, NSLayoutAttribute.CenterY, NSLayoutRelation.Equal, this, NSLayoutAttribute.CenterY, 1, 0);
+
+					AddConstraints (new[] { this.leftEdgeLeftConstraint, this.leftEdgeVCenterConstraint });
+				}
+			}
+		}
+
 		public override void ViewWillMoveToSuperview (NSView newSuperview)
 		{
 			if (newSuperview == null && EditorView != null)
@@ -61,5 +89,8 @@ namespace Xamarin.PropertyEditing.Mac
 			set { this.label.TextColor = value; }
 		}
 #endif
+
+		private NSView leftEdgeView;
+		private NSLayoutConstraint leftEdgeLeftConstraint, leftEdgeVCenterConstraint;
 	}
 }

Xamarin.PropertyEditing.Mac/PropertyEditorPanel.cs

@@ -175,6 +175,7 @@ namespace Xamarin.PropertyEditing.Mac
 			((NSView)this.header.ContentView).AddSubview (this.tabStack);
 
 			this.propertyTable = new FirstResponderOutlineView {
+				IndentationPerLevel = 0,
 				RefusesFirstResponder = true,
 				SelectionHighlightStyle = NSTableViewSelectionHighlightStyle.None,
 				HeaderView = null,
@@ -184,9 +185,6 @@ namespace Xamarin.PropertyEditing.Mac
 			var propertyEditors = new NSTableColumn (PropertyEditorColId);
 			this.propertyTable.AddColumn (propertyEditors);
 
-			// Set OutlineTableColumn or the arrows showing children/expansion or they will not be drawn
-			this.propertyTable.OutlineTableColumn = propertyEditors;
-
 			var tableContainer = new NSScrollView {
 				TranslatesAutoresizingMaskIntoConstraints = false,
 			};
@@ -279,18 +277,6 @@ namespace Xamarin.PropertyEditing.Mac
 			{
 				return true;
 			}
-
-			public override CGRect GetCellFrame (nint column, nint row)
-			{
-				var super = base.GetCellFrame (column, row);
-				if (column == 0) {
-					var obj = (NSObjectFacade)ItemAtRow (row);
-					if (obj.Target is PropertyGroupViewModel)
-						return new CGRect (0, super.Top, super.Right - (super.Left / 2), super.Height);
-				}
-
-				return super;
-			}
 		}
 	}
 }

Xamarin.PropertyEditing.Mac/PropertyTableDelegate.cs

@@ -53,14 +53,30 @@ namespace Xamarin.PropertyEditing.Mac
 			GetVMGroupCellItendifiterFromFacade (item, out evm, out group, out cellIdentifier);
 
 			if (group != null) {
-				var labelContainer = (UnfocusableTextField)outlineView.MakeView (LabelIdentifier, this);
+				var labelContainer = (NSView)outlineView.MakeView (CategoryIdentifier, this);
 				if (labelContainer == null) {
-					labelContainer = new UnfocusableTextField {
-						Identifier = LabelIdentifier,
+					labelContainer = new NSView {
+						Identifier = CategoryIdentifier,
 					};
+
+					var disclosure = outlineView.MakeView ("NSOutlineViewDisclosureButtonKey", outlineView);
+					disclosure.TranslatesAutoresizingMaskIntoConstraints = false;
+					labelContainer.AddSubview (disclosure);
+
+					var label = new UnfocusableTextField {
+						TranslatesAutoresizingMaskIntoConstraints = false
+					};
+					labelContainer.AddSubview (label);
+
+					labelContainer.AddConstraints (new[] {
+						NSLayoutConstraint.Create (disclosure, NSLayoutAttribute.CenterY, NSLayoutRelation.Equal, labelContainer, NSLayoutAttribute.CenterY, 1, 0),
+						NSLayoutConstraint.Create (disclosure, NSLayoutAttribute.Left, NSLayoutRelation.Equal, labelContainer, NSLayoutAttribute.Left, 1, 4),
+						NSLayoutConstraint.Create (label, NSLayoutAttribute.Left, NSLayoutRelation.Equal, disclosure, NSLayoutAttribute.Right, 1, 0),
+						NSLayoutConstraint.Create (label, NSLayoutAttribute.Height, NSLayoutRelation.Equal, labelContainer, NSLayoutAttribute.Height, 1, 0),
+					});
 				}
 
-				labelContainer.StringValue = group.Category;
+				((UnfocusableTextField)labelContainer.Subviews[1]).StringValue = group.Category;
 
 				if (this.dataSource.DataContext.GetIsExpanded (group.Category)) {
 					SynchronizationContext.Current.Post (s => {
@@ -92,7 +108,17 @@ namespace Xamarin.PropertyEditing.Mac
 			if (editor != null) {
 				editor.ViewModel = evm;
 
-				bool openObjectRow = evm is ObjectPropertyViewModel && outlineView.IsItemExpanded (item);
+				var ovm = evm as ObjectPropertyViewModel;
+				if (ovm != null && editorOrContainer is EditorContainer container) {
+					if (container.LeftEdgeView == null) {
+						if (ovm.CanDelve)
+							container.LeftEdgeView = outlineView.MakeView ("NSOutlineViewDisclosureButtonKey", outlineView);
+					} else if (!ovm.CanDelve) {
+						container.LeftEdgeView = null;
+					}
+				}
+
+				bool openObjectRow = ovm != null && outlineView.IsItemExpanded (item);
 				if (!openObjectRow) {
 					var parent = outlineView.GetParent (item);
 					openObjectRow = (parent != null && ((NSObjectFacade)parent).Target is ObjectPropertyViewModel);
@@ -119,13 +145,18 @@ namespace Xamarin.PropertyEditing.Mac
 
 		public override void ItemDidExpand (NSNotification notification)
 		{
-			if (this.isExpanding)
-				return;
-
 			NSObjectFacade facade = notification.UserInfo.Values[0] as NSObjectFacade;
 			var outline = (NSOutlineView)notification.Object;
 			nint row = outline.RowForItem (facade);
 
+			if (this.isExpanding) {
+				NSView view = outline.GetView (0, row, makeIfNecessary: true);
+				if (view.Subviews[0] is NSButton expander)
+					expander.State = NSCellStateValue.On;
+
+				return;
+			}
+
 			if (facade.Target is PanelGroupViewModel group)
 				this.dataSource.DataContext.SetIsExpanded (group.Category, isExpanded: true);
 			else if (facade.Target is ObjectPropertyViewModel ovm) {
@@ -136,13 +167,18 @@ namespace Xamarin.PropertyEditing.Mac
 
 		public override void ItemDidCollapse (NSNotification notification)
 		{
-			if (this.isExpanding)
-				return;
-
 			NSObjectFacade facade = notification.UserInfo.Values[0] as NSObjectFacade;
 			var outline = (NSOutlineView)notification.Object;
 			nint row = outline.RowForItem (facade);
 
+			if (this.isExpanding) {
+				NSView view = outline.GetView (0, row, makeIfNecessary: true);
+				if (view.Subviews[0] is NSButton expander)
+					expander.State = NSCellStateValue.Off;
+
+				return;
+			}
+
 			if (facade.Target is PanelGroupViewModel group)
 				this.dataSource.DataContext.SetIsExpanded (group.Category, isExpanded: false);
 			else if (facade.Target is ObjectPropertyViewModel ovm) {
@@ -203,7 +239,7 @@ namespace Xamarin.PropertyEditing.Mac
 			}
 		}
 
-		public const string LabelIdentifier = "label";
+		public const string CategoryIdentifier = "label";
 
 		private PropertyTableDataSource dataSource;
 		private bool isExpanding;