MoveGameObjectsUpAndDown.cs

using System;
using UnityEditor;
using UnityEngine;

namespace Kogane.Internal
{
    /// <summary>
    /// JetBrains Rider のように Ctrl + Alt + Shift + ↑↓ でゲームオブジェクトの順番を移動できるエディタ拡張
    /// </summary>
    [InitializeOnLoad]
    internal static class MoveGameObjectsUpAndDown
    {
        //================================================================================
        // 関数(static)
        //================================================================================
        /// <summary>
        /// コンストラクタ
        /// </summary>
        static MoveGameObjectsUpAndDown()
        {
            EditorApplication.hierarchyWindowItemOnGUI += HierarchyWindowItemOnGui;
            EditorApplication.hierarchyWindowItemOnGUI += HierarchyWindowItemOnGui;
        }

        /// <summary>
        /// Hierarchy の項目を描画する時に呼び出されます
        /// </summary>
        private static void HierarchyWindowItemOnGui
        (
            int  instanceID,
            Rect selectionRect
        )
        {
            var current = Event.current;
            var keyCode = current.keyCode;

            if ( !current.control ) return;
            if ( !current.alt ) return;
            if ( !current.shift ) return;
            if ( current.type != EventType.KeyDown ) return;
            if ( keyCode != KeyCode.UpArrow && keyCode != KeyCode.DownArrow ) return;

            current.Use();

            foreach ( var transform in Selection.transforms )
            {
                var siblingIndex = transform.GetSiblingIndex();

                var nextSiblingIndex = keyCode switch
                {
                    KeyCode.UpArrow   => Mathf.Max( 0, siblingIndex - 1 ),
                    KeyCode.DownArrow => siblingIndex + 1,
                    _                 => throw new ArgumentOutOfRangeException()
                };

                transform.SetSiblingIndex( nextSiblingIndex );
            }
        }
    }
}