core/Editor/IconFoldoutGroupAttributeDrawer.cs

using Sirenix.OdinInspector.Editor;
using Sirenix.OdinInspector.Editor.ValueResolvers;
using Sirenix.Utilities.Editor;
using UnityEngine;
using UnityEditor;
using KairoEngine.Core;

namespace KairoEngine.Core.Editor
{
    public class IconFoldoutGroupAttributeDrawer :  OdinGroupDrawer<IconFoldoutGroupAttribute>
    {
        private LocalPersistentContext<bool> isExpanded;

        protected override void Initialize()
        {
            this.isExpanded = this.GetPersistentValue<bool>(
                "IconFoldoutGroupAttributeDrawer.isExpanded",
                GeneralDrawerConfig.Instance.ExpandFoldoutByDefault);
        }

        protected override void DrawPropertyLayout(GUIContent label)
        {
            SirenixEditorGUI.BeginBox();
            SirenixEditorGUI.BeginBoxHeader();
            string text = ValueResolver.GetForString(this.Property, this.Attribute.text, null).GetValue();
            string path = ValueResolver.GetForString(this.Property, this.Attribute.iconPath, null).GetValue();
            Texture2D image = EditorGUIUtility.FindTexture(path);
            if(image == null)
            {
                image = new Texture2D(1, 1);
                var data = System.IO.File.ReadAllBytes(path);
                if(data != null) image.LoadImage(data);
                image.Apply();
            }
            label = new GUIContent(text);
            var styleCollapse = new GUIStyle(EditorStyles.foldout);
            Rect rect = EditorGUILayout.GetControlRect();
            GUI.DrawTexture(new Rect(rect.x, rect.y + 2, 14, 14), image);
            rect.x += 18;
            rect.width -= 18;
            this.isExpanded.Value = SirenixEditorGUI.Foldout(rect, this.isExpanded.Value, label, styleCollapse);
            SirenixEditorGUI.EndBoxHeader();

            if (SirenixEditorGUI.BeginFadeGroup(this, this.isExpanded.Value))
            {
                for (int i = 0; i < this.Property.Children.Count; i++)
                {
                    this.Property.Children[i].Draw();
                }
            }

            SirenixEditorGUI.EndFadeGroup();
            SirenixEditorGUI.EndBox();
        }
    }
}