- added SimpleListView.cs

- added StateButton.cs
- added SavedToggleShaderProperty.cs
- re-organized UIElements stuff into dedicated folder
- added HandleBarPartial.uxml to visualize handle bars for any SimpleListView.cs

Author: Doppelkeks

Editor/UIElements.meta

@@ -0,0 +1,107 @@
+using System;
+using UnityEditor;
+using UnityEngine;
+using UnityEngine.UIElements;
+
+namespace EditorUI {
+    /// <summary>
+    /// Helper class for managing a toggleable shader property with saved state.
+    /// </summary>
+    public class SavedToggleShaderProperty {
+        /// <summary>
+        /// Key in the EditorPrefs for storing the property state.
+        /// </summary>
+        private readonly string prefsKey;
+
+        /// <summary>
+        /// Name of the shader variable.
+        /// </summary>
+        private readonly string variableName;
+
+        /// <summary>
+        /// Display name of the toggle.
+        /// </summary>
+        private readonly string displayName;
+
+        /// <summary>
+        /// Default state of the property.
+        /// </summary>
+        private readonly bool defaultState;
+
+        /// <summary>
+        /// Flag indicating whether to negate the state of the property.
+        /// </summary>
+        private readonly bool negateState;
+
+        /// <summary>
+        /// Gets or sets the current state of the property.
+        /// </summary>
+        public bool IsPropertyActive {
+            get => EditorPrefs.GetBool(prefsKey, defaultState);
+            set => EditorPrefs.SetBool(prefsKey, value);
+        }
+
+        /// <summary>
+        /// Constructor for SavedToggleShaderProperty.
+        /// </summary>
+        /// <param name="baseKey">Base key for the EditorPrefs.</param>
+        /// <param name="variableName">Name of the shader variable.</param>
+        /// <param name="displayName">Display name of the toggle.</param>
+        /// <param name="defaultState">Default state of the property.</param>
+        /// <param name="negateState">Flag indicating whether to negate the state of the property.</param>
+        public SavedToggleShaderProperty(string baseKey, string variableName, string displayName, bool defaultState = true, bool negateState = false) {
+            prefsKey = baseKey + "." + variableName;
+            this.variableName = variableName;
+            this.displayName = displayName;
+            this.defaultState = defaultState;
+            this.negateState = negateState;
+        }
+
+        /// <summary>
+        /// Creates a GUI element for the toggle property.
+        /// </summary>
+        /// <param name="root">Root VisualElement to attach the toggle to.</param>
+        /// <param name="OnChange">Action to be invoked when the toggle value changes.</param>
+        public void CreateGUI(VisualElement root, Action OnChange) {
+            Toggle toggle = new Toggle(displayName) { value = IsPropertyActive };
+            toggle.RegisterValueChangedCallback((evt) => {
+                IsPropertyActive = evt.newValue;
+                OnChange?.Invoke();
+            });
+            root.Add(toggle);
+        }
+
+        /// <summary>
+        /// Draws the toggle property in an Editor window.
+        /// </summary>
+        /// <param name="rect">Position and size of the GUI element.</param>
+        /// <returns>True if the property value changed, false otherwise.</returns>
+        public bool Draw(Rect rect) {
+            EditorGUI.BeginChangeCheck();
+
+            bool newState = EditorGUI.Toggle(rect, displayName, IsPropertyActive);
+            if (Event.current.type == EventType.MouseUp && rect.Contains(Event.current.mousePosition)) {
+                newState = !IsPropertyActive;
+            }
+
+            if (EditorGUI.EndChangeCheck() || newState != IsPropertyActive) {
+                IsPropertyActive = newState;
+                return true;
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Sets the shader property in a MaterialPropertyBlock.
+        /// </summary>
+        /// <param name="propertyBlock">The MaterialPropertyBlock to set the property in.</param>
+        public void SetProperty(MaterialPropertyBlock propertyBlock) {
+            if (!negateState) {
+                propertyBlock.SetFloat(variableName, IsPropertyActive ? 1 : 0);
+            } else {
+                propertyBlock.SetFloat(variableName, IsPropertyActive ? 0 : 1);
+            }
+        }
+    }
+}

Editor/UIElements/SavedToggleShaderProperty.cs

@@ -0,0 +1,137 @@
+using System;
+using UnityEditor;
+using UnityEngine.UIElements;
+
+namespace EditorUI {
+    /// <summary>
+    /// Base class for a simple list view.
+    /// </summary>
+    public abstract class SimpleListView : ListView {
+        /// <summary>
+        /// Name of the item row container.
+        /// </summary>
+        private readonly string itemRowContainer = DEFAULT_ITEMROW_CONTAINER_NAME;
+
+        /// <summary>
+        /// Default name for the item row container.
+        /// </summary>
+        private const string DEFAULT_ITEMROW_CONTAINER_NAME = nameof(SimpleListView) + "_" + nameof(itemRowContainer);
+
+        /// <summary>
+        /// Constant value for the handle bars partial GUID.
+        /// </summary>
+        private const string HANDLE_BARS_PARTIAL_GUID = "cef02cc912d280d4cb3ea263d3012dc7";
+
+        /// <summary>
+        /// Partial to identifiy a list view in ui elements
+        /// </summary>
+        private const string LISTVIEW_IDENTIFIER_PARTIAL = "unity-list-view__";
+
+        /// <summary>
+        /// Event for when an item is added.
+        /// </summary>
+        public Action addClicked;
+
+        /// <summary>
+        /// Event for when an item is removed.
+        /// </summary>
+        public Action removeClicked;
+
+        /// <summary>
+        /// Event for creating a row in the list view.
+        /// </summary>
+        public Action<VisualElement> createRow;
+
+        /// <summary>
+        /// Static variable for the handle bars partial.
+        /// </summary>
+        private static VisualTreeAsset _handleBarsPartial = null;
+
+        /// <summary>
+        /// Property for accessing the handle bars partial.
+        /// </summary>
+        public static VisualTreeAsset HandleBarsPartial {
+            get {
+                if (_handleBarsPartial == null) {
+                    _handleBarsPartial = AssetDatabase.LoadAssetAtPath<VisualTreeAsset>(HANDLE_BARS_PARTIAL_GUID);
+                }
+                return _handleBarsPartial;
+            }
+        }
+
+        /// <summary>
+        /// Constructor for SimpleListView.
+        /// </summary>
+        /// <param name="reorderable">Flag to enable or disable reordering of items.</param>
+        /// <param name="showAddRemoveFooter">Flag to show or hide the add/remove footer.</param>
+        /// <param name="itemRowContainer">Name of the item row container.</param>
+        /// <param name="createRow">Action for creating a row in the list view.</param>
+        /// <param name="addClicked">Action for handling the add button click event.</param>
+        /// <param name="removeClicked">Action for handling the remove button click event.</param>
+        /// <param name="doDefaultMake">Flag to indicate whether to use the default make item behavior.</param>
+        public SimpleListView(bool reorderable = true, bool showAddRemoveFooter = true, string itemRowContainer = DEFAULT_ITEMROW_CONTAINER_NAME, Action<VisualElement> createRow = null, Action addClicked = null, Action removeClicked = null, bool doDefaultMake = false) {
+            // Set flags
+            this.reorderable = reorderable;
+            this.showAddRemoveFooter = showAddRemoveFooter;
+            this.itemRowContainer = itemRowContainer;
+
+            // Set up events
+            this.addClicked = addClicked;
+            this.removeClicked = removeClicked;
+            this.createRow = createRow;
+
+            showBorder = true;
+            if (!doDefaultMake) {
+                makeItem = MakeItem;
+            }
+            selectionType = SelectionType.Single;
+            reorderMode = ListViewReorderMode.Simple;
+            showBoundCollectionSize = false;
+
+            // Your ListView needs to take all the remaining space
+            style.flexGrow = 1;
+
+            // Overwrite default button behaviors due to bugs in ListView code
+            schedule.Execute(() => {
+                virtualizationMethod = CollectionVirtualizationMethod.DynamicHeight;
+                Button removeButton = this.Q<Button>(LISTVIEW_IDENTIFIER_PARTIAL+"remove-button");
+                removeButton.clickable = null;
+                removeButton.clicked += RemoveClicked;
+                Button addButton = this.Q<Button>(LISTVIEW_IDENTIFIER_PARTIAL+"add-button");
+                addButton.clickable = null;
+                addButton.clicked += AddClicked;
+            });
+        }
+
+        /// <summary>
+        /// Method for creating a new item in the list view.
+        /// </summary>
+        /// <returns>The created item as a VisualElement.</returns>
+        private VisualElement MakeItem() {
+            VisualElement rowItem = new VisualElement();
+            if (reorderable) {
+                // Add handlebars with hand symbol to imply dragging support
+                rowItem.Add(HandleBarsPartial.Instantiate()[0]);
+            }
+            rowItem.AddToClassList(itemRowContainer);
+            createRow?.Invoke(rowItem);
+            return rowItem;
+        }
+
+        /// <summary>
+        /// Method for handling the add button click event.
+        /// </summary>
+        protected virtual void AddClicked() {
+            addClicked?.Invoke();
+            ClearSelection();
+        }
+
+        /// <summary>
+        /// Method for handling the remove button click event.
+        /// </summary>
+        protected virtual void RemoveClicked() {
+            removeClicked?.Invoke();
+            ClearSelection();
+        }
+    }
+}

Editor/UIElements/SavedToggleShaderProperty.cs.meta

@@ -0,0 +1,79 @@
+using System;
+using UnityEditor;
+using UnityEngine.UIElements;
+
+namespace EditorUI {
+    /// <summary>
+    /// Custom button with state functionality.
+    /// </summary>
+    public class StateButton : Button {
+        /// <summary>
+        /// Key for storing the state in the EditorPrefs.
+        /// </summary>
+        private string stateEditorPrefsKey;
+
+        /// <summary>
+        /// Current state of the button.
+        /// </summary>
+        private bool state;
+
+        /// <summary>
+        /// Action to be performed after the button is clicked.
+        /// </summary>
+        private Action afterClicked;
+
+        /// <summary>
+        /// CSS class to apply when the button is active.
+        /// </summary>
+        private string buttonActiveClass;
+
+        /// <summary>
+        /// Gets the current state of the button.
+        /// </summary>
+        public bool State => state;
+
+        /// <summary>
+        /// Constructor for the StateButton class.
+        /// </summary>
+        /// <param name="stateEditorPrefsKey">Key for storing the state in the EditorPrefs.</param>
+        /// <param name="buttonLabel">Label text of the button.</param>
+        /// <param name="buttonActiveClass">CSS class to apply when the button is active.</param>
+        /// <param name="afterClicked">Action to be performed after the button is clicked.</param>
+        /// <param name="defaultStateValue">Default state value of the button.</param>
+        public StateButton(string stateEditorPrefsKey, string buttonLabel, string buttonActiveClass, Action afterClicked = null, bool defaultStateValue = true) {
+            this.stateEditorPrefsKey = stateEditorPrefsKey;
+            this.afterClicked = afterClicked;
+            this.buttonActiveClass = buttonActiveClass;
+
+            text = buttonLabel;
+            clicked -= OnButtonClicked;
+            clicked += OnButtonClicked;
+
+            OnButtonClickedBase(EditorPrefs.GetBool(stateEditorPrefsKey, defaultStateValue));
+        }
+
+        /// <summary>
+        /// Event handler for button click event.
+        /// </summary>
+        private void OnButtonClicked() {
+            OnButtonClickedBase(!state);
+        }
+
+        /// <summary>
+        /// Sets the button state and updates its appearance.
+        /// </summary>
+        /// <param name="stateToSet">State value to set.</param>
+        private void OnButtonClickedBase(bool stateToSet) {
+            state = stateToSet;
+
+            if (state) {
+                AddToClassList(buttonActiveClass);
+            } else {
+                RemoveFromClassList(buttonActiveClass);
+            }
+
+            EditorPrefs.SetBool(stateEditorPrefsKey, state);
+            afterClicked?.Invoke();
+        }
+    }
+}