feat: Generates group views dynamically

Assets/Cryville.Common/Unity/UI/RecyclerView.cs

@@ -0,0 +1,160 @@
+using System;
+using System.Collections.Generic;
+using UnityEngine;
+using UnityEngine.EventSystems;
+using UnityEngine.UI;
+
+namespace Cryville.Common.Unity.UI {
+	public delegate void LoadItemHandler(int index, GameObject gameObject);
+	[RequireComponent(typeof(RectTransform))]
+	public class RecyclerView : UIBehaviour {
+		[SerializeField]
+		private GameObject m_itemTemplate;
+		public GameObject ItemTemplate {
+			get { return m_itemTemplate; }
+			set { m_itemTemplate = value; /*OnTemplateUpdate();*/ }
+		}
+		public LoadItemHandler LoadItem { private get; set; }
+
+		public enum Axis {
+			Horizontal = 0,
+			Vertical = 1,
+		}
+		[SerializeField]
+		private Axis m_direction;
+		public Axis Direction {
+			get { return m_direction; }
+			set { m_direction = value; /*OnFrameUpdate();*/ }
+		}
+
+		[SerializeField]
+		RectOffset m_padding;
+		public RectOffset Padding {
+			get => m_padding;
+			set => m_padding = value;
+		}
+
+		[SerializeField]
+		float m_spacing;
+		public float Spacing {
+			get => m_spacing;
+			set => m_spacing = value;
+		}
+
+		[SerializeField]
+		private int m_itemCount = 3;
+		public int ItemCount {
+			get { return m_itemCount; }
+			set { m_itemCount = value; /*OnRefresh();*/ }
+		}
+
+		RectTransform _rectTransform;
+		protected override void Awake() {
+			_rectTransform = GetComponent<RectTransform>();
+		}
+
+		const float _placeholderLength = 100;
+		int _firstIndex, _lastIndex;
+		readonly Stack<GameObject> _pool = new();
+		void Update() {
+			int axis = (int)m_direction;
+			int sign = m_direction == 0 ? 1 : -1;
+			float padding = axis == 0 ? m_padding.left : m_padding.top;
+			if (_rectTransform.parent is not RectTransform parentTransform)
+				throw new InvalidOperationException("Parent transform is not RectTransform");
+
+			Vector2 apos = _rectTransform.anchoredPosition;
+			float pos = apos[axis] + padding;
+			float childPos = _firstIndex * _placeholderLength + padding;
+			float visibleLength = parentTransform.rect.size[axis];
+
+			//// Add preceding
+			//while (_firstIndex > 0 && childPos > pos) {
+			//	var child = Rent();
+			//	child.transform.SetAsFirstSibling();
+			//	LoadItem(--_firstIndex, child);
+			//	pos += GetLength(axis, child.transform) - _placeholderLength;
+			//	childPos -= _placeholderLength;
+			//}
+
+			//// Remove preceding
+			//while (_firstIndex < _lastIndex) {
+			//	var child = transform.GetChild(0);
+			//	float len = GetLength(axis, child.transform);
+			//	if (childPos + len > pos) break;
+			//	Return(child.gameObject);
+			//	_firstIndex++;
+			//	pos += _placeholderLength - len;
+			//	childPos += _placeholderLength;
+			//}
+
+			//apos[axis] = pos;
+			//_rectTransform.anchoredPosition = apos;
+
+			// Layout existing
+			int index = _firstIndex;
+			float layoutToPos = pos + visibleLength;
+			for (; index < _lastIndex && childPos < layoutToPos; index++) {
+				var child = (RectTransform)transform.GetChild(index - _firstIndex);
+				LayoutChild(axis, sign, ref childPos, child);
+			}
+
+			// Remove following
+			for (; _lastIndex > index; --_lastIndex) {
+				var child = (RectTransform)transform.GetChild(index - _firstIndex);
+				Return(child.gameObject);
+			}
+
+			// Add following (and layout)
+			while (_lastIndex < m_itemCount && childPos < layoutToPos) {
+				var child = Rent();
+				if (child.transform is not RectTransform childTransform)
+					throw new InvalidOperationException("Child transform is not RectTransform");
+				childTransform.SetSiblingIndex(_lastIndex - _firstIndex);
+				LoadItem(_lastIndex++, child);
+				LayoutChild(axis, sign, ref childPos, childTransform);
+			}
+
+			Vector2 gsize = _rectTransform.sizeDelta;
+			gsize[axis] = childPos + (m_itemCount - _lastIndex) * _placeholderLength + (axis == 0 ? m_padding.horizontal : m_padding.vertical);
+			_rectTransform.sizeDelta = gsize;
+		}
+		static float GetLength(int axis, Transform child) {
+			if (child is not RectTransform childTransform)
+				throw new InvalidOperationException("Child transform is not RectTransform");
+			return LayoutUtility.GetPreferredSize(childTransform, axis);
+		}
+		void LayoutChild(int axis, int sign, ref float childPos, RectTransform childTransform) {
+			Vector2 cpos = childTransform.anchoredPosition;
+			cpos[axis] = childPos * sign;
+			cpos[axis ^ 1] = axis == 1 ? m_padding.left : m_padding.top;
+			childTransform.anchoredPosition = cpos;
+
+			Vector2 size = childTransform.sizeDelta;
+			size[axis ^ 1] = _rectTransform.rect.size[axis ^ 1] - (axis == 1 ? m_padding.horizontal : m_padding.vertical);
+			childTransform.sizeDelta = size;
+
+			childPos += GetLength(axis, childTransform) + m_spacing;
+		}
+
+		GameObject Rent() {
+			if (_pool.TryPop(out var ret)) {
+				ret.SetActive(true);
+				return ret;
+			}
+			return Instantiate(m_itemTemplate, transform, false);
+		}
+		void Return(GameObject child) {
+			child.transform.SetAsLastSibling();
+			child.SetActive(false);
+			_pool.Push(child);
+		}
+
+		public void InvalidateAll() {
+			for (; _lastIndex > _firstIndex; --_lastIndex) {
+				var child = (RectTransform)transform.GetChild(0);
+				Return(child.gameObject);
+			}
+		}
+	}
+}

Assets/Cryville.Common/Unity/UI/RecyclerView.cs.meta

@@ -0,0 +1,11 @@
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+guid: 1257c1f4490f1d64bb8fc52a9abed1ae
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
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