[BetterSceneLoader] Dropdown filter

src/BetterSceneLoader.Core/BetterSceneLoader.Core.projitems

@@ -14,6 +14,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)ImageGrid.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)BetterSceneLoader.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)DropdownAutoScroll.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)DropdownFilter.cs" />
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Resources\loadicon" />

src/BetterSceneLoader.Core/DropdownFilter.cs

@@ -0,0 +1,227 @@
+using System.Collections.Generic;
+using System.Text.RegularExpressions;
+using UILib;
+using UnityEngine;
+using UnityEngine.UI;
+
+namespace BetterSceneLoader
+{
+    internal class DropdownFilter : MonoBehaviour
+    {
+        [SerializeField] private RectTransform _filterRect;
+        [SerializeField] private InputField _filterField;
+        [SerializeField] private RectTransform _content;
+        [SerializeField] private RectTransform _clearButtonRect;
+        [SerializeField] private string _persistentKeyword;
+
+        private static readonly Dictionary<string, string> _persistentFilterMap = new Dictionary<string, string>();
+        private static readonly float _clearButtonAnchorX = 0.16f;
+
+        private float _itemStride = 20f;
+
+        /// <summary>
+        /// Add filter UI to dropdown
+        /// </summary>
+        /// <param name="target">Target dropdown</param>
+        /// <param name="persistentKeyword">Name for persistent filter. A persisted filter will continue to hold the filter after it is closed.</param>
+        public static void AddFilterUI(Dropdown target, string persistentKeyword = null)
+        {
+            var menuTemplate = target.transform.Find("Template");
+
+            if(menuTemplate == null)
+                return;
+
+            var filter = menuTemplate.GetComponent<DropdownFilter>();
+
+            if(filter != null)
+                return;
+
+            filter = menuTemplate.gameObject.AddComponent<DropdownFilter>();
+            filter._persistentKeyword = persistentKeyword;
+
+            var filterField = UIUtility.CreateInputField("Filter", menuTemplate.transform, "Filter");
+            filter._filterField = filterField;
+
+            float uiMargin = 2f;
+            float filterUIHeight = GetItemSize(target) + uiMargin;
+
+            var templateRect = (RectTransform)menuTemplate.transform;
+            templateRect.anchoredPosition = new Vector2(0, -filterUIHeight + uiMargin + uiMargin);
+
+            var filterRect = (RectTransform)filterField.transform;
+            filter._filterRect = filterRect;
+
+            filterRect.anchorMin = new Vector2(_clearButtonAnchorX, 0f);
+            filterRect.anchorMax = new Vector2(1f, 0f);
+            filterRect.offsetMin = new Vector2(0, -filterUIHeight);
+            filterRect.offsetMax = new Vector2(0, 0);
+            filterRect.sizeDelta = new Vector2(0, filterUIHeight);
+
+            var clearButton = UIUtility.CreateButton("ClearFilter", menuTemplate.transform, "Clear");
+            var clearButtonRect = (RectTransform)clearButton.transform;
+            filter._clearButtonRect = clearButtonRect;
+            clearButtonRect.anchorMin = new Vector2(0f, 0);
+            clearButtonRect.anchorMax = new Vector2(_clearButtonAnchorX, 0);
+            clearButtonRect.offsetMin = new Vector2(0, -filterUIHeight);
+            clearButtonRect.offsetMax = new Vector2(0, 0);
+            clearButtonRect.sizeDelta = new Vector2(0, filterUIHeight);
+
+            var content = (RectTransform)target.transform.Find("Template/Viewport/Content");
+            filter._content = content;
+
+            //Add layout groups/element so that items are automatically aligned
+            var contentLayoutGroup = content.gameObject.AddComponent<VerticalLayoutGroup>();
+
+            contentLayoutGroup.childForceExpandWidth = true;
+            contentLayoutGroup.childForceExpandHeight = false;
+            contentLayoutGroup.childControlWidth = true;
+            contentLayoutGroup.childControlHeight = false;
+
+            content.Find("Item").gameObject.AddComponent<LayoutElement>();
+        }
+
+        private void Start()
+        {
+            if(_filterRect == null)
+                return;
+
+            SetUIPosition();
+
+            _filterField.onValueChanged.AddListener(OnChangeFilter);
+            _filterField.onEndEdit.AddListener(OnEndEditFilter);
+
+            if(_content.childCount >= 3)
+            {
+                var item1 = (RectTransform)_content.GetChild(1);
+                var item2 = (RectTransform)_content.GetChild(2);
+                _itemStride = Mathf.Abs(item1.offsetMin.y - item2.offsetMin.y);
+            }
+            else
+            {
+                _itemStride = 20f;
+            }
+
+            _clearButtonRect.GetComponent<Button>().onClick.AddListener(ClearFilter);
+            RestoreFilter();
+        }
+
+        private void SaveFilter()
+        {
+            if(string.IsNullOrEmpty(_persistentKeyword))
+                return;
+
+            _persistentFilterMap[_persistentKeyword] = _filterField.text;
+        }
+
+        private void RestoreFilter()
+        {
+            if(string.IsNullOrEmpty(_persistentKeyword) || !_persistentFilterMap.ContainsKey(_persistentKeyword))
+                return;
+
+            var filter = _persistentFilterMap[_persistentKeyword];
+            _filterField.text = filter;
+        }
+
+        private void ClearFilter()
+        {
+            _filterField.text = "";
+            SaveFilter();
+        }
+
+        private void OnEndEditFilter(string filter)
+        {
+            SaveFilter();
+        }
+
+        private void OnChangeFilter(string filter)
+        {
+            if(string.IsNullOrEmpty(filter))
+                filter = "*";
+
+            var regex = new Regex(Regex.Escape(filter).Replace("\\*", ".*").Replace("\\?", "."), RegexOptions.IgnoreCase);
+            int activeItems = 0;
+
+            foreach(Transform item in _content)
+            {
+                var name = item.name;
+
+                if(name.EndsWith(": Reset"))
+                {
+                    ++activeItems;
+                    continue;
+                }                    
+
+                int colon = name.IndexOf(":");
+                if(colon < 0)
+                    continue;                    
+
+                bool isShown = regex.IsMatch(name.Substring(colon + 1).Trim());
+                item.gameObject.SetActive(isShown);
+                if(isShown)
+                    ++activeItems;
+            }
+
+            var sizeDelta = _content.sizeDelta;
+            sizeDelta.y = _itemStride * activeItems + 8f;
+            _content.sizeDelta = sizeDelta;
+
+            var scrollbar = GetComponentInChildren<Scrollbar>();
+            if(scrollbar != null)
+            {
+                scrollbar.value = 1f;
+                scrollbar.Rebuild(CanvasUpdate.Prelayout);
+            }   
+        }
+
+        /// <summary>
+        /// Set the position of the filter UI.
+        /// The drop-down UI is displayed either up or down depending on position. 
+        /// Change the position of the filter UI accordingly.
+        /// </summary>
+        private void SetUIPosition()
+        {
+            float height = _filterRect.sizeDelta.y;
+            float offset = 2f;
+            var dropdownRect = (RectTransform)transform;
+
+            if(dropdownRect.offsetMax.y > 0)
+            {
+                _filterRect.anchorMin = new Vector2(_clearButtonAnchorX, 0f);
+                _filterRect.anchorMax = new Vector2(1f, 0f);
+                _filterRect.offsetMin = new Vector2(0, -height + offset);
+                _filterRect.offsetMax = new Vector2(0, offset);
+
+                _clearButtonRect.anchorMin = new Vector2(0f, 0f);
+                _clearButtonRect.anchorMax = new Vector2(_clearButtonAnchorX, 0f);
+                _clearButtonRect.offsetMin = new Vector2(0, -height + offset);
+                _clearButtonRect.offsetMax = new Vector2(0, offset);
+            }
+            else
+            {
+                _filterRect.anchorMin = new Vector2(_clearButtonAnchorX, 1f);
+                _filterRect.anchorMax = new Vector2(1f, 1f);
+                _filterRect.offsetMin = new Vector2(0, -offset);
+                _filterRect.offsetMax = new Vector2(0, height - offset);
+
+                _clearButtonRect.anchorMin = new Vector2(0, 1f);
+                _clearButtonRect.anchorMax = new Vector2(_clearButtonAnchorX, 1f);
+                _clearButtonRect.offsetMin = new Vector2(0, -offset);
+                _clearButtonRect.offsetMax = new Vector2(0, height - offset);
+            }
+        }
+
+        private static float GetItemSize(Dropdown dropdown)
+        {
+            if(dropdown.itemText != null)
+            {
+                return dropdown.itemText.rectTransform.rect.height;
+            }
+            else if(dropdown.itemImage != null)
+            {
+                return dropdown.itemImage.rectTransform.rect.height;
+            }
+
+            return 20f;
+        }
+    }
+}

src/BetterSceneLoader.Core/ImageGrid.cs

@@ -64,7 +64,7 @@ public void ShowWindow(bool flag)
         {
             UISystem.gameObject.SetActive(flag);
             toolbarToggle?.SetValue(flag);
-            category?.template.SetRect(0f, 1f, 0f, 0f, 0f, 0f, dropdownWidth, mainPanel.rectTransform.rect.height / 2);
+            category?.template.SetRect(0f, 1f, 0f, 0f, 0f, headerSize - marginSize, dropdownWidth, mainPanel.rectTransform.rect.height / 2);
         }
 
         public void UpdateWindow()
@@ -141,6 +141,7 @@ public void CreateUI(string name, int sortingOrder, string titleText)
                 PopulateGrid();
             });
             DropdownAutoScroll.Setup(category);
+            DropdownFilter.AddFilterUI(category, "BetterSceneLoaderDropdown");
 
             var refresh = UIUtility.CreateButton("RefreshButton", drag.transform, "Refresh");
             refresh.transform.SetRect(0f, 0f, 0f, 1f, curPos, 0f, curPos+=80f);