虚拟列表增加动态ScrollBarWenScrollable

Editor/RecyclerView/RecyclerViewEditor.cs

@@ -57,6 +57,7 @@ namespace AlicizaX.UI.Editor
 
         private SerializedProperty _templates;
         private SerializedProperty _showScrollBar;
+        private SerializedProperty _showScrollBarOnlyWhenScrollable;
         private SerializedProperty _scrollbar;
 
         #endregion
@@ -120,6 +121,7 @@ namespace AlicizaX.UI.Editor
         {
             _templates = serializedObject.FindProperty("templates");
             _showScrollBar = serializedObject.FindProperty("showScrollBar");
+            _showScrollBarOnlyWhenScrollable = serializedObject.FindProperty("showScrollBarOnlyWhenScrollable");
             _scrollbar = serializedObject.FindProperty("scrollbar");
         }
 
@@ -303,6 +305,13 @@ namespace AlicizaX.UI.Editor
                 {
                     HandleScrollBarToggle();
                 }
+
+                if (_showScrollBar.boolValue)
+                {
+                    EditorGUILayout.PropertyField(
+                        _showScrollBarOnlyWhenScrollable,
+                        new GUIContent("Only When Scrollable", "Hide the scrollbar and disable list scrolling when content does not overflow the viewport."));
+                }
             }
         }
 

Runtime/RecyclerView/RecyclerView.cs

@@ -38,6 +38,7 @@ namespace AlicizaX.UI
         [HideInInspector] [SerializeField] private ViewHolder[] templates;
         [HideInInspector] [SerializeField] private RectTransform content;
         [HideInInspector] [SerializeField] private bool showScrollBar;
+        [HideInInspector] [SerializeField] private bool showScrollBarOnlyWhenScrollable;
         [HideInInspector] [SerializeField] private Scrollbar scrollbar;
 
         #endregion
@@ -200,6 +201,20 @@ namespace AlicizaX.UI
             }
         }
 
+        /// <summary>
+        /// 是否仅在内容超出可视区域时显示滚动条并允许滚动
+        /// </summary>
+        public bool ShowScrollBarOnlyWhenScrollable
+        {
+            get => showScrollBarOnlyWhenScrollable;
+            set
+            {
+                if (showScrollBarOnlyWhenScrollable == value) return;
+                showScrollBarOnlyWhenScrollable = value;
+                RequestLayout();
+            }
+        }
+
         #endregion
 
 
@@ -333,13 +348,13 @@ namespace AlicizaX.UI
             scroller.Snap = snap;
             scroller.OnValueChanged.AddListener(OnScrollChanged);
             scroller.OnMoveStoped.AddListener(OnMoveStoped);
+            UpdateScrollerState();
         }
 
         private void ConfigureScrollbar()
         {
             if (!showScrollBar || scrollbar == null) return;
 
-            scrollbar.gameObject.SetActive(scroll);
             scrollbar.onValueChanged.AddListener(OnScrollbarChanged);
 
             var scrollbarEx = scrollbar.gameObject.GetComponent<ScrollbarEx>();
@@ -349,6 +364,7 @@ namespace AlicizaX.UI
             }
 
             scrollbarEx.OnDragEnd = OnScrollbarDragEnd;
+            UpdateScrollbarVisibility();
         }
 
         #endregion
@@ -428,15 +444,28 @@ namespace AlicizaX.UI
         /// </summary>
         public void RequestLayout()
         {
+            if (layoutManager == null)
+            {
+                UpdateScrollbarVisibility();
+                return;
+            }
+
             layoutManager.SetContentSize();
 
-            if (scroller == null) return;
+            if (scroller == null)
+            {
+                UpdateScrollbarVisibility();
+                return;
+            }
 
             scroller.Direction = direction;
             scroller.ViewSize = layoutManager.ViewportSize;
             scroller.ContentSize = layoutManager.ContentSize;
+            scroller.Position = Mathf.Clamp(scroller.Position, 0, scroller.MaxPosition);
 
+            UpdateScrollerState();
             UpdateScrollbarVisibility();
+            UpdateScrollbarValue(scroller.Position);
         }
 
         #endregion
@@ -661,11 +690,14 @@ namespace AlicizaX.UI
 
         private void UpdateScrollbarVisibility()
         {
-            if (scrollbar == null || scroller == null || layoutManager.ContentSize == Vector2.zero)
+            if (scrollbar == null)
+            {
                 return;
+            }
 
             bool shouldShow = ShouldShowScrollbar();
             scrollbar.gameObject.SetActive(shouldShow);
+            scrollbar.interactable = shouldShow;
 
             if (shouldShow)
             {
@@ -676,16 +708,22 @@ namespace AlicizaX.UI
 
         private bool ShouldShowScrollbar()
         {
-            if (direction == Direction.Custom) return false;
+            if (!showScrollBar || !scroll || scrollbar == null || scroller == null || layoutManager == null || !SupportsOverflowCheck())
+            {
+                return false;
+            }
 
-            if (direction == Direction.Vertical)
+            if (!HasValidScrollMetrics())
             {
-                return layoutManager.ContentSize.y > layoutManager.ViewportSize.y;
+                return false;
             }
-            else // Horizontal
+
+            if (!ShouldLimitScrollToOverflow())
             {
-                return layoutManager.ContentSize.x > layoutManager.ViewportSize.x;
+                return true;
             }
+
+            return HasScrollableContent();
         }
 
         private void ConfigureScrollbarDirection()
@@ -707,6 +745,61 @@ namespace AlicizaX.UI
             }
         }
 
+        private void UpdateScrollerState()
+        {
+            if (scroller == null)
+            {
+                return;
+            }
+
+            scroller.enabled = scroll && (!ShouldLimitScrollToOverflow() || HasScrollableContent());
+        }
+
+        private bool ShouldLimitScrollToOverflow()
+        {
+            return showScrollBar && showScrollBarOnlyWhenScrollable && SupportsOverflowCheck();
+        }
+
+        private bool HasScrollableContent()
+        {
+            if (layoutManager == null)
+            {
+                return false;
+            }
+
+            if (direction == Direction.Vertical)
+            {
+                return layoutManager.ContentSize.y > layoutManager.ViewportSize.y;
+            }
+
+            if (direction == Direction.Horizontal)
+            {
+                return layoutManager.ContentSize.x > layoutManager.ViewportSize.x;
+            }
+
+            return false;
+        }
+
+        private bool SupportsOverflowCheck()
+        {
+            return direction == Direction.Vertical || direction == Direction.Horizontal;
+        }
+
+        private bool HasValidScrollMetrics()
+        {
+            if (direction == Direction.Vertical)
+            {
+                return layoutManager.ContentSize.y > 0f && layoutManager.ViewportSize.y > 0f;
+            }
+
+            if (direction == Direction.Horizontal)
+            {
+                return layoutManager.ContentSize.x > 0f && layoutManager.ViewportSize.x > 0f;
+            }
+
+            return false;
+        }
+
         private void SnapToNearestItem()
         {
             int index = layoutManager.PositionToIndex(GetScrollPosition());