using System;
using System.Collections.Generic;
using UnityEditor;
using UnityEditorInternal;
using UnityEngine;
using UnityEngine.UIElements;
namespace UnityEditor.ShaderGraph.Drawing
{
internal class ReorderableListView<T> : VisualElement
{
// generic control to display and allow the user to directly reorder/add/remove from a list of T
// the List we are editing
List<T> m_DataList;
// this is how we get the string to display for each item
Func<T, string> m_GetDisplayTextFunc;
readonly bool m_AllowReorder;
ReorderableList m_ReorderableList;
List<string> m_TextList = new List<string>();
IMGUIContainer m_Container;
GUIStyle m_LabelStyle;
int m_SelectedIndex = -1;
string m_HeaderLabel;
// list of options for the drop down menu when the user clicks the add button
public delegate List<string> GetAddMenuOptionsDelegate();
public GetAddMenuOptionsDelegate GetAddMenuOptions;
// callback when the user clicks on an item from the AddMenu
public delegate void OnAddMenuItemDelegate(List<T> targetList, int addMenuOptionIndex, string addMenuOption);
public OnAddMenuItemDelegate OnAddMenuItemCallback;
// callback to override how an item is removed from the list
internal delegate void RemoveItemDelegate(List<T> list, int itemIndex);
public RemoveItemDelegate RemoveItemCallback;
// callback when the list is reordered
internal delegate void ListReorderedDelegate(List<T> reorderedList);
public ListReorderedDelegate OnListReorderedCallback;
internal ReorderableListView(
List<T> dataList,
string header = "Reorder data:",
bool allowReorder = true,
Func<T, string> getDisplayText = null)
{
m_DataList = dataList;
m_HeaderLabel = header;
m_AllowReorder = allowReorder;
// setup GetDisplayTextFunc
if (getDisplayText == null)
m_GetDisplayTextFunc = data => data.ToString();
else
m_GetDisplayTextFunc = getDisplayText;
RebuildTextList();
// should we set up a new style sheet? allow user overrides?
styleSheets.Add(Resources.Load<StyleSheet>("Styles/ReorderableSlotListView"));
m_Container = new IMGUIContainer(() => OnGUIHandler()) { name = "ListContainer" };
Add(m_Container);
}
void RebuildTextList()
{
m_TextList.Clear();
try
{
foreach (var data in m_DataList)
{
m_TextList.Add(m_GetDisplayTextFunc(data));
}
}
catch (Exception e)
{
Debug.Log("Exception: " + e.ToString() + " while handling ReorderableListView of type: " + typeof(T).ToString());
}
}
internal void RecreateList(List<T> dataList)
{
m_DataList = dataList;
// Create reorderable list from data list
m_ReorderableList = new ReorderableList(
dataList,
typeof(T), // the type of the elements in dataList
m_AllowReorder, // draggable (to reorder)
true, // displayHeader
true, // displayAddButton
true); // displayRemoveButton
}
private void OnGUIHandler()
{
try
{
if (m_ReorderableList == null)
{
RecreateList(m_DataList);
AddCallbacks();
}
using (var changeCheckScope = new EditorGUI.ChangeCheckScope())
{
m_ReorderableList.index = m_SelectedIndex;
m_ReorderableList.DoLayoutList();
if (changeCheckScope.changed)
{
// Do things when changed
}
}
}
catch (Exception e)
{
Debug.Log("Exception: " + e.ToString() + " while handling ReorderableListView of type: " + typeof(T).ToString());
}
}
private void AddCallbacks()
{
m_ReorderableList.drawHeaderCallback = (Rect rect) =>
{
var labelRect = new Rect(rect.x, rect.y, rect.width - 10, rect.height);
EditorGUI.LabelField(labelRect, m_HeaderLabel);
};
// Draw Element
m_ReorderableList.drawElementCallback = (Rect rect, int index, bool isActive, bool isFocused) =>
{
EditorGUI.LabelField(
new Rect(rect.x, rect.y, rect.width / 2, EditorGUIUtility.singleLineHeight),
m_TextList[index], EditorStyles.label);
};
// Element height
m_ReorderableList.elementHeightCallback = (int indexer) => { return m_ReorderableList.elementHeight; };
// Add callback delegates
m_ReorderableList.onSelectCallback += SelectEntry; // should we propagate this up if user wants to do something with selection?
m_ReorderableList.onReorderCallback += ReorderEntries;
m_ReorderableList.onAddDropdownCallback += OnAddDropdownMenu;
m_ReorderableList.onRemoveCallback += OnRemove;
}
private void SelectEntry(ReorderableList list)
{
m_SelectedIndex = list.index;
}
private void ReorderEntries(ReorderableList list)
{
RebuildTextList();
OnListReorderedCallback(m_DataList);
}
private void OnAddDropdownMenu(Rect buttonRect, ReorderableList list)
{
//created the drop down menu on add item from the listview
List<string> addMenuOptions;
if (GetAddMenuOptions != null)
addMenuOptions = GetAddMenuOptions();
else
addMenuOptions = new List<string>();
var menu = new GenericMenu();
for (int optionIndex = 0; optionIndex < addMenuOptions.Count; optionIndex++)
{
string optionText = addMenuOptions[optionIndex];
// disable any option that is already in the text list
bool optionEnabled = !m_TextList.Contains(optionText);
// need to make a copy so the lambda will capture the value, not the variable
int localOptionIndex = optionIndex;
if (optionEnabled)
menu.AddItem(new GUIContent(optionText), false, () => OnAddMenuClicked(localOptionIndex, optionText));
else
menu.AddDisabledItem(new GUIContent(optionText));
}
menu.ShowAsContext();
}
void OnAddMenuClicked(int optionIndex, string optionText)
{
OnAddMenuItemCallback(m_DataList, optionIndex, optionText);
// if anything was changed about the list in the callback, we need to rebuild our text list
RebuildTextList();
}
void OnRemove(ReorderableList list)
{
int indexToRemove = list.index;
if (indexToRemove < 0)
indexToRemove = m_DataList.Count - 1;
if (indexToRemove >= 0)
{
if (RemoveItemCallback != null)
{
RemoveItemCallback(m_DataList, indexToRemove);
}
else
{
// no callback provided, do it ourselves
m_DataList.RemoveAt(indexToRemove);
}
// if anything was changed about the list in the callback, we need to rebuild our text list
RebuildTextList();
}
}
}
}