Allows ListView trigger the Enter and Leave events. (#1508)

* Allows ListView trigger the Enter and Leave events.

* Added unit test for Enter and Leave events to all views.

Terminal.Gui/Views/Button.cs

@@ -256,7 +256,7 @@ namespace Terminal.Gui {
 		///<inheritdoc/>
 		public override void PositionCursor ()
 		{
-			if (HotKey == Key.Unknown) {
+			if (HotKey == Key.Unknown && text != "") {
 				for (int i = 0; i < base.Text.RuneCount; i++) {
 					if (base.Text [i] == text [0]) {
 						Move (i, 0);

Terminal.Gui/Views/ComboBox.cs

@@ -238,7 +238,7 @@ namespace Terminal.Gui {
 
 			search.CursorPosition = search.Text.RuneCount;
 
-			return true;
+			return base.OnEnter (view);
 		}
 
 		///<inheritdoc/>
@@ -251,7 +251,7 @@ namespace Terminal.Gui {
 				listview.TabStop = false;
 			}
 
-			return true;
+			return base.OnLeave (view);
 		}
 
 		/// <summary>

Terminal.Gui/Views/ListView.cs

@@ -673,7 +673,6 @@ namespace Terminal.Gui {
 			if (lastSelectedItem == -1) {
 				EnsuresVisibilitySelectedItem ();
 				OnSelectedChanged ();
-				return true;
 			}
 
 			return base.OnEnter (view);
@@ -684,10 +683,9 @@ namespace Terminal.Gui {
 		{
 			if (lastSelectedItem > -1) {
 				lastSelectedItem = -1;
-				return true;
 			}
 
-			return false;
+			return base.OnLeave (view);
 		}
 
 		void EnsuresVisibilitySelectedItem ()

Terminal.Gui/Views/TabView.cs

@@ -174,7 +174,7 @@ namespace Terminal.Gui {
 				int startAtY = Math.Max (0, GetTabHeight (true) - 1);
 
 				DrawFrame (new Rect (0, startAtY, bounds.Width,
-			       bounds.Height - spaceAtBottom - startAtY), 0, true);
+			       Math.Max (bounds.Height - spaceAtBottom - startAtY, 0)), 0, true);
 			}
 
 			if (Tabs.Any ()) {

Terminal.Gui/Views/TextValidateField.cs

@@ -454,7 +454,7 @@ namespace Terminal.Gui {
 			// Fixed = true, is for inputs thar have fixed width, like masked ones.
 			// Fixed = false, is for normal input.
 			// When it's right-aligned and it's a normal input, the cursor behaves differently.
-			if (provider.Fixed == false && TextAlignment == TextAlignment.Right) {
+			if (provider?.Fixed == false && TextAlignment == TextAlignment.Right) {
 				Move (cursorPosition + left - 1, 0);
 			} else {
 				Move (cursorPosition + left, 0);
@@ -591,7 +591,7 @@ namespace Terminal.Gui {
 		public override bool ProcessKey (KeyEvent kb)
 		{
 			if (provider == null) {
-				return true;
+				return false;
 			}
 
 			switch (kb.Key) {

UnitTests/AllViewsTests.cs

@@ -22,51 +22,65 @@ namespace Terminal.Gui.Views {
 		public bool Constructors_FullTest (Type type)
 		{
 			foreach (var ctor in type.GetConstructors ()) {
-				if (type.IsGenericType && type.IsTypeDefinition) {
-					List<Type> gTypes = new List<Type> ();
+				var view = GetTypeInitializer (type, ctor);
+				if (view != null) {
+					Assert.True (type.FullName == view.GetType ().FullName);
+				}
+			}
 
-					foreach (var args in type.GetGenericArguments ()) {
-						gTypes.Add (typeof (object));
-					}
-					type = type.MakeGenericType (gTypes.ToArray ());
+			return true;
+		}
 
-					Assert.IsType (type, (View)Activator.CreateInstance (type));
+		private static View GetTypeInitializer (Type type, ConstructorInfo ctor)
+		{
+			View viewType = null;
 
-				} else {
-					ParameterInfo [] paramsInfo = ctor.GetParameters ();
-					Type paramType;
-					List<object> pTypes = new List<object> ();
-
-					if (type.IsGenericType) {
-						foreach (var args in type.GetGenericArguments ()) {
-							paramType = args.GetType ();
-							if (args.Name == "T") {
-								pTypes.Add (typeof (object));
-							} else {
-								AddArguments (paramType, pTypes);
-							}
-						}
-					}
+			if (type.IsGenericType && type.IsTypeDefinition) {
+				List<Type> gTypes = new List<Type> ();
 
-					foreach (var p in paramsInfo) {
-						paramType = p.ParameterType;
-						if (p.HasDefaultValue) {
-							pTypes.Add (p.DefaultValue);
+				foreach (var args in type.GetGenericArguments ()) {
+					gTypes.Add (typeof (object));
+				}
+				type = type.MakeGenericType (gTypes.ToArray ());
+
+				Assert.IsType (type, (View)Activator.CreateInstance (type));
+
+			} else {
+				ParameterInfo [] paramsInfo = ctor.GetParameters ();
+				Type paramType;
+				List<object> pTypes = new List<object> ();
+
+				if (type.IsGenericType) {
+					foreach (var args in type.GetGenericArguments ()) {
+						paramType = args.GetType ();
+						if (args.Name == "T") {
+							pTypes.Add (typeof (object));
 						} else {
 							AddArguments (paramType, pTypes);
 						}
-
 					}
+				}
 
-					if (type.IsGenericType && !type.IsTypeDefinition) {
-						Assert.IsType (type, (View)Activator.CreateInstance (type));
+				foreach (var p in paramsInfo) {
+					paramType = p.ParameterType;
+					if (p.HasDefaultValue) {
+						pTypes.Add (p.DefaultValue);
 					} else {
-						Assert.IsType (type, ctor.Invoke (pTypes.ToArray ()));
+						AddArguments (paramType, pTypes);
 					}
+
+				}
+
+				if (type.IsGenericType && !type.IsTypeDefinition) {
+					viewType = (View)Activator.CreateInstance (type);
+					Assert.IsType (type, viewType);
+				} else {
+					viewType = (View)ctor.Invoke (pTypes.ToArray ());
+					Assert.IsType (type, viewType);
 				}
 			}
 
-			return true;
+			return viewType;
 		}
 
 		private static void AddArguments (Type paramType, List<object> pTypes)
@@ -108,5 +122,63 @@ namespace Terminal.Gui.Views {
 			}
 			return types;
 		}
+
+		[Fact]
+		public void AllViews_Enter_Leave_Events ()
+		{
+			foreach (var type in GetAllViewClassesCollection ()) {
+				Application.Init (new FakeDriver (), new FakeMainLoop (() => FakeConsole.ReadKey (true)));
+
+				var top = Application.Top;
+				var vType = GetTypeInitializer (type, type.GetConstructor (Array.Empty<Type> ()));
+				if (vType == null) {
+					Application.Shutdown ();
+					continue;
+				}
+				vType.X = 0;
+				vType.Y = 0;
+				vType.Width = 10;
+				vType.Height = 1;
+
+				var view = new View () {
+					X = 0,
+					Y = 1,
+					Width = 10,
+					Height = 1,
+					CanFocus = true
+				};
+				var vTypeEnter = 0;
+				var vTypeLeave = 0;
+				var viewEnter = 0;
+				var viewLeave = 0;
+
+				vType.Enter += _ => vTypeEnter++;
+				vType.Leave += _ => vTypeLeave++;
+				view.Enter += _ => viewEnter++;
+				view.Leave += _ => viewLeave++;
+
+				top.Add (vType, view);
+				Application.Begin (top);
+
+				if (!vType.CanFocus || (vType is Toplevel && ((Toplevel)vType).Modal)) {
+					Application.Shutdown ();
+					continue;
+				}
+
+				if (vType is TextView) {
+					top.ProcessKey (new KeyEvent (Key.Tab | Key.CtrlMask, new KeyModifiers ()));
+				} else {
+					top.ProcessKey (new KeyEvent (Key.Tab, new KeyModifiers ()));
+				}
+				top.ProcessKey (new KeyEvent (Key.Tab, new KeyModifiers ()));
+
+				Assert.Equal (2, vTypeEnter);
+				Assert.Equal (1, vTypeLeave);
+				Assert.Equal (1, viewEnter);
+				Assert.Equal (1, viewLeave);
+
+				Application.Shutdown ();
+			}
+		}
 	}
 }