Utility.AsyncProgressBar (Unity 2019 or lower)

gistfile1.txt

using UnityEditor;
using System.Reflection;

namespace NGToolsEditor
{
	using UnityEngine;

	[AssemblyVerifier]
	public class Utility
	{
#if !UNITY_2020_1_OR_NEWER
		private static bool			initializeAsyncProgressBarMetadata;
		private static PropertyInfo	AsyncProgressBarProgressInfo;
		private static MethodInfo	AsyncProgressBarDisplayMethod;
		private static MethodInfo	AsyncProgressBarClearMethod;
#endif

		public static string	GetAsyncProgressBarInfo()
		{
#if !UNITY_2020_1_OR_NEWER
			if (Utility.initializeAsyncProgressBarMetadata == false)
			{
				Utility.initializeAsyncProgressBarMetadata = true;
				Utility.LazyInitializeAsyncProgressBarMetadata();
			}

			if (Utility.AsyncProgressBarProgressInfo != null)
				return Utility.AsyncProgressBarProgressInfo.GetValue(null, null) as string;
#endif
			return string.Empty;
		}

		public static void	AsyncProgressBarDisplay(string progressInfo, float progress)
		{
#if !UNITY_2020_1_OR_NEWER
			if (Utility.initializeAsyncProgressBarMetadata == false)
			{
				Utility.initializeAsyncProgressBarMetadata = true;
				Utility.LazyInitializeAsyncProgressBarMetadata();
			}

			if (Utility.AsyncProgressBarDisplayMethod != null)
				Utility.AsyncProgressBarDisplayMethod.Invoke(null, new object[] { progressInfo, progress });
#endif
		}

		public static void	AsyncProgressBarClear()
		{
#if !UNITY_2020_1_OR_NEWER
			if (Utility.initializeAsyncProgressBarMetadata == false)
			{
				Utility.initializeAsyncProgressBarMetadata = true;
				Utility.LazyInitializeAsyncProgressBarMetadata();
			}

			if (Utility.AsyncProgressBarClearMethod != null)
				Utility.AsyncProgressBarClearMethod.Invoke(null, null);
#endif
		}

#if !UNITY_2020_1_OR_NEWER
		[AssemblyVerifier]
		private static void	LazyInitializeAsyncProgressBarMetadata()
		{
			Type	AsyncProgressBarType = AssemblyVerifier.TryGetType(typeof(EditorWindow).Assembly, "UnityEditor.AsyncProgressBar");

			if (AsyncProgressBarType != null)
			{
				Utility.AsyncProgressBarProgressInfo = AssemblyVerifier.TryGetProperty(AsyncProgressBarType, "progressInfo", BindingFlags.Static | BindingFlags.Public);
				Utility.AsyncProgressBarDisplayMethod = AssemblyVerifier.TryGetMethod(AsyncProgressBarType, "Display", BindingFlags.Static | BindingFlags.Public);
				Utility.AsyncProgressBarClearMethod = AssemblyVerifier.TryGetMethod(AsyncProgressBarType, "Clear", BindingFlags.Static | BindingFlags.Public);
			}
		}
#endif
	}
}