Implemented PageHandler proof of concept, fixed something with scrollviews

src/Explorer.csproj

@@ -240,6 +240,7 @@
     <Compile Include="UI\Main\Pages\SearchPage.cs" />
     <Compile Include="UI\Main\PanelDragger.cs" />
     <Compile Include="UI\InteractiveValue\InteractiveValue.cs" />
+    <Compile Include="UI\Shared\PageHandler.cs" />
     <Compile Include="UI\Shared\Syntax.cs" />
     <Compile Include="UI\UIManager.cs" />
     <Compile Include="Unstrip\ImageConversion\ImageConversionUnstrip.cs" />

src/UI/Main/MainMenu.cs

@@ -65,8 +65,12 @@ namespace ExplorerBeta.UI.Main
             if (m_activePage == page || page == null)
                 return;
 
+            m_activePage?.Content?.SetActive(false);
+
             m_activePage = page;
 
+            m_activePage.Content?.SetActive(true);
+
             var button = page.RefNavbarButton;
 
             var colors = button.colors;
@@ -87,16 +91,7 @@ namespace ExplorerBeta.UI.Main
 
         #region UI Interaction Callbacks
 
-        private void OnPressHide()
+        // ... none needed yet
-        {
-            ExplorerCore.ShowMenu = false;
-        }
-
-        private void OnNavButtonPressed(BaseMenuPage page)
-        {
-            ExplorerCore.Log($"Pressed '{page.Name}'");
-            SetPage(page);
-        }
 
         #endregion
 
@@ -159,7 +154,7 @@ namespace ExplorerBeta.UI.Main
             var hideBtnObj = UIFactory.CreateButton(titleBar);
 
             var hideBtn = hideBtnObj.GetComponent<Button>();
-            hideBtn.onClick.AddListener(new Action(OnPressHide));
+            hideBtn.onClick.AddListener(new Action(() => { ExplorerCore.ShowMenu = false; }));
             var colorBlock = hideBtn.colors;
             colorBlock.normalColor = new Color(65f/255f, 23f/255f, 23f/255f);
             colorBlock.pressedColor = new Color(35f/255f, 10f/255f, 10f/255f);
@@ -207,7 +202,7 @@ namespace ExplorerBeta.UI.Main
 
                 page.RefNavbarButton = btn;
 
-                btn.onClick.AddListener(new Action(() => { OnNavButtonPressed(page); }));
+                btn.onClick.AddListener(new Action(() => { SetPage(page); }));
 
                 var text = btnObj.GetComponentInChildren<Text>();
                 text.text = page.Name;

src/UI/Main/Pages/HomePage.cs

@@ -2,8 +2,10 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using ExplorerBeta;
 using ExplorerBeta.UI;
 using ExplorerBeta.UI.Main;
+using ExplorerBeta.UI.Shared;
 using UnityEngine;
 using UnityEngine.UI;
 
@@ -13,7 +15,7 @@ namespace Explorer.UI.Main.Pages
     {
         public override string Name => "Home";
 
-        private GameObject m_mainViewport;
+        private PageHandler m_sceneListPages;
 
         public override void Init()
         {
@@ -31,8 +33,8 @@ namespace Explorer.UI.Main.Pages
         {
             var parent = MainMenu.Instance.PageViewport;
 
-            m_mainViewport = UIFactory.CreateHorizontalGroup(parent);
+            Content = UIFactory.CreateHorizontalGroup(parent);
-            var mainGroup = m_mainViewport.GetComponent<HorizontalLayoutGroup>();
+            var mainGroup = Content.GetComponent<HorizontalLayoutGroup>();
             mainGroup.padding.left = 3;
             mainGroup.padding.right = 3;
             mainGroup.padding.top = 3;
@@ -43,7 +45,7 @@ namespace Explorer.UI.Main.Pages
             mainGroup.childControlHeight = true;
             mainGroup.childControlWidth = true;
 
-            var leftPaneObj = UIFactory.CreateVerticalGroup(m_mainViewport, new Color(72f / 255f, 72f / 255f, 72f / 255f));
+            var leftPaneObj = UIFactory.CreateVerticalGroup(Content, new Color(72f / 255f, 72f / 255f, 72f / 255f));
             var leftLayout = leftPaneObj.AddComponent<LayoutElement>();
             leftLayout.minWidth = 350;
             leftLayout.flexibleWidth = 0;
@@ -59,7 +61,7 @@ namespace Explorer.UI.Main.Pages
             leftGroup.childForceExpandWidth = false;
             leftGroup.childForceExpandHeight = true;
 
-            var rightPaneObj = UIFactory.CreateVerticalGroup(m_mainViewport, new Color(72f / 255f, 72f / 255f, 72f / 255f));
+            var rightPaneObj = UIFactory.CreateVerticalGroup(Content, new Color(72f / 255f, 72f / 255f, 72f / 255f));
             var rightLayout = rightPaneObj.AddComponent<LayoutElement>();
             rightLayout.flexibleWidth = 999999;
 
@@ -68,6 +70,28 @@ namespace Explorer.UI.Main.Pages
             rightGroup.childForceExpandWidth = true;
             rightGroup.childControlHeight = true;
             rightGroup.childControlWidth = true;
+
+            ConstructScenePane(leftPaneObj);
+        }
+
+        private void ConstructScenePane(GameObject leftPane)
+        {
+            m_sceneListPages = new PageHandler(100);
+            m_sceneListPages.ConstructUI(leftPane);
+            m_sceneListPages.OnPageChanged += RefreshSceneObjectList;
+
+            var scrollTest = UIFactory.CreateScrollView(leftPane, out GameObject content);
+            for (int i = 0; i < 50; i++)
+            {
+                var obj = UIFactory.CreateLabel(content, TextAnchor.MiddleCenter);
+                var text = obj.GetComponent<Text>();
+                text.text = "Hello world " + i;
+            }
+        }
+
+        private void RefreshSceneObjectList()
+        {
+            ExplorerCore.Log("Would update scene list here");
         }
 
         #endregion

src/UI/Shared/PageHandler.cs

@@ -0,0 +1,155 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using UnityEngine;
+using UnityEngine.UI;
+using ExplorerBeta.Config;
+
+namespace ExplorerBeta.UI.Shared
+{
+    public enum Turn
+    {
+        Left,
+        Right
+    }
+
+    public class PageHandler
+    {
+        public PageHandler(int listCount)
+        {
+            ListCount = listCount;
+            m_itemsPerPage = ModConfig.Instance?.Default_Page_Limit ?? 20;
+        }
+
+        // callback for when the page is turned
+        public event Action OnPageChanged;
+
+        // set and maintained by owner of list
+        public int ListCount { get; set; }
+
+        // For now this is just set when the PageHandler is created, based on config.
+        // At some point I might make it possible to change this after creation again.
+        private readonly int m_itemsPerPage;
+
+        private int m_currentPage;
+
+        // the last page index (not using "index" to avoid confusion with next property)
+        public int LastPage => (int)Math.Ceiling(ListCount / (decimal)m_itemsPerPage) - 1;
+
+        // The index of the first element of the current page
+        public int IndexOffset
+        {
+            get
+            {
+                int offset = m_currentPage * m_itemsPerPage;
+
+                if (offset >= ListCount)
+                {
+                    offset = 0;
+                    m_currentPage = 0;
+                }
+
+                return offset;
+            }
+        }
+
+        public void TurnPage(Turn direction)
+        {
+            if (direction == Turn.Left)
+            {
+                if (m_currentPage > 0)
+                {
+                    m_currentPage--;
+                    OnPageChanged?.Invoke();
+                    RefreshUI();
+                }
+            }
+            else
+            {
+                if (m_currentPage < LastPage)
+                {
+                    m_currentPage++;
+                    OnPageChanged?.Invoke();
+                    RefreshUI();
+                }
+            }
+        }
+
+        #region UI
+
+        // TODO
+
+        private GameObject m_pageUIHolder;
+        private Text m_currentPageLabel;
+
+        public void Show() => m_pageUIHolder?.SetActive(true);
+
+        public void Hide() => m_pageUIHolder?.SetActive(false);
+
+        public void ConstructUI(GameObject parent)
+        {
+            m_pageUIHolder = UIFactory.CreateHorizontalGroup(parent);
+
+            var image = m_pageUIHolder.GetComponent<Image>();
+            image.color = new Color(0f, 0f, 0f, 0f);
+
+            var parentGroup = m_pageUIHolder.GetComponent<HorizontalLayoutGroup>();
+            parentGroup.childForceExpandHeight = true;
+            parentGroup.childForceExpandWidth = false;
+            parentGroup.childControlWidth = true;
+            parentGroup.childControlHeight = true;
+
+            var parentLayout = m_pageUIHolder.AddComponent<LayoutElement>();
+            parentLayout.minHeight = 45;
+            parentLayout.preferredHeight = 45;
+            parentLayout.flexibleHeight = 3;
+            parentLayout.minWidth = 300;
+            parentLayout.preferredWidth = 300;
+            parentLayout.flexibleWidth = 0;
+
+            var leftBtnObj = UIFactory.CreateButton(m_pageUIHolder);
+            var leftBtn = leftBtnObj.GetComponent<Button>();
+            leftBtn.onClick.AddListener(new Action(() => { TurnPage(Turn.Left); }));
+            var leftBtnText = leftBtnObj.GetComponentInChildren<Text>();
+            leftBtnText.text = "<";
+            var leftBtnLayout = leftBtnObj.AddComponent<LayoutElement>();
+            leftBtnLayout.flexibleHeight = 0;
+            leftBtnLayout.flexibleWidth = 0;
+            leftBtnLayout.minWidth = 30;
+            leftBtnLayout.preferredWidth = 30;
+            leftBtnLayout.minHeight = 30;
+            leftBtnLayout.preferredHeight = 30;
+
+            var labelObj = UIFactory.CreateLabel(m_pageUIHolder, TextAnchor.MiddleCenter);
+            m_currentPageLabel = labelObj.GetComponent<Text>();
+            m_currentPageLabel.text = "Page 1 / TODO";
+            var textLayout = labelObj.AddComponent<LayoutElement>();
+            textLayout.flexibleWidth = 1.5f;
+            textLayout.preferredWidth = 200;
+
+            var rightBtnObj = UIFactory.CreateButton(m_pageUIHolder);
+            var rightBtn = rightBtnObj.GetComponent<Button>();
+            rightBtn.onClick.AddListener(new Action(() => { TurnPage(Turn.Right); }));
+            var rightBtnText = rightBtnObj.GetComponentInChildren<Text>();
+            rightBtnText.text = ">";
+            var rightBtnLayout = rightBtnObj.AddComponent<LayoutElement>();
+            rightBtnLayout.flexibleHeight = 0;
+            rightBtnLayout.flexibleWidth = 0;
+            rightBtnLayout.preferredWidth = 30;
+            rightBtnLayout.minWidth = 30;
+            rightBtnLayout.minHeight = 30;
+            rightBtnLayout.preferredHeight = 30;
+
+            RefreshUI();
+        }
+
+        public void RefreshUI()
+        {
+            m_currentPageLabel.text = $"Page {m_currentPage + 1} / {LastPage + 1}";
+        }
+
+        #endregion
+    }
+}

src/UI/UIFactory.cs

@@ -55,9 +55,11 @@ namespace ExplorerBeta.UI
 		private static void SetDefaultColorTransitionValues(Selectable slider)
 		{
 			ColorBlock colors = slider.colors;
-			colors.highlightedColor = new Color(0.4f, 0.4f, 0.4f);
+			colors.normalColor = new Color(0.3f, 0.3f, 0.3f);
-			colors.pressedColor = new Color(0.05f, 0.05f, 0.05f);
+			colors.highlightedColor = new Color(0.45f, 0.45f, 0.45f);
+			colors.pressedColor = new Color(0.1f, 0.1f, 0.1f);
 			colors.disabledColor = new Color(0.7f, 0.7f, 0.7f);
+			slider.colors = colors;
 		}
 
 		private static void SetParentAndAlign(GameObject child, GameObject parent)
@@ -530,6 +532,12 @@ namespace ExplorerBeta.UI
 		{
 			GameObject scrollObj = CreateUIObject("Scroll View", parent);
 
+			var mainLayout = scrollObj.AddComponent<LayoutElement>();
+			mainLayout.flexibleWidth = 999;
+			mainLayout.flexibleHeight = 999;
+			mainLayout.preferredHeight = 200;
+			mainLayout.preferredWidth = 200;
+
 			GameObject viewportObj = CreateUIObject("Viewport", scrollObj);
 
 			var viewportGroup = viewportObj.AddComponent<VerticalLayoutGroup>();