支持编辑器和打包后

使用方法：创建 FolderBrowserHelper.cs文件

using System;
using System.IO;
using System.Runtime.InteropServices;
using UnityEngine;

/// <summary>
/// 调用系统代码,打开本地文件夹
/// </summary>
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public class OpenDialogueFile
{
    public int structSize = 0;
    public IntPtr dlgOwner = IntPtr.Zero;
    public IntPtr instance = IntPtr.Zero;
    public String filter = null;
    public String customFilter = null;
    public int maxCustFilter = 0;
    public int filterIndex = 0;
    public String file = null;
    public int maxFile = 0;
    public String fileTitle = null;
    public int maxFileTitle = 0;
    public String initialDir = null;
    public String title = null;
    public int flags = 0;
    public short fileOffset = 0;
    public short fileExtension = 0;
    public String defExt = null;
    public IntPtr custData = IntPtr.Zero;
    public IntPtr hook = IntPtr.Zero;
    public String templateName = null;
    public IntPtr reservedPtr = IntPtr.Zero;
    public int reservedInt = 0;
    public int flagsEx = 0;
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public class OpenDialogDir
{
    public IntPtr hwndOwner = IntPtr.Zero;
    public IntPtr pidlRoot = IntPtr.Zero;
    public String pszDisplayName = null;
    public String lpszTitle = null;
    public UInt32 ulFlags = 0;
    public IntPtr lpfn = IntPtr.Zero;
    public IntPtr lParam = IntPtr.Zero;
    public int iImage = 0;
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public class OpenFileName
{
    public int structSize = 0;
    public IntPtr dlgOwner = IntPtr.Zero;
    public IntPtr instance = IntPtr.Zero;
    public String filter = null;
    public String customFilter = null;
    public int maxCustFilter = 0;
    public int filterIndex = 0;
    public String file = null;
    public int maxFile = 0;
    public String fileTitle = null;
    public int maxFileTitle = 0;
    public String initialDir = null;
    public String title = null;
    public int flags = 0;
    public short fileOffset = 0;
    public short fileExtension = 0;
    public String defExt = null;
    public IntPtr custData = IntPtr.Zero;
    public IntPtr hook = IntPtr.Zero;
    public String templateName = null;
    public IntPtr reservedPtr = IntPtr.Zero;
    public int reservedInt = 0;
    public int flagsEx = 0;
}

public static class FolderBrowserHelper
{

    #region Window

    [DllImport("Comdlg32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]
    private static extern bool GetOpenFileName([In, Out] OpenFileName ofn);

    [DllImport("Comdlg32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]
    private static extern bool GetSaveFileName([In, Out] OpenFileName ofn);

    [DllImport("Comdlg32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]
    private static extern bool GetOpenFileName([In, Out] OpenDialogueFile ofn);

    [DllImport("Comdlg32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]
    private static extern bool GetSaveFileName([In, Out] OpenDialogueFile ofn);

    [DllImport("shell32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]
    private static extern IntPtr SHBrowseForFolder([In, Out] OpenDialogDir ofn);

    [DllImport("shell32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]
    private static extern bool SHGetPathFromIDList([In] IntPtr pidl, [In, Out] char[] fileName);

    #endregion

    public const string IMAGEFILTER = "图片文件(*.jpg;*.png)\0*.jpg;*.png";
    public const string ALLFILTER = "所有文件(*.*)\0*.*";
    public const string VIDEOFILTER = "视频文件(*.mp4;*.avi)\0*.mp4;*.avi";
    public const string JSONFILTER = "视频文件(*.txt;*.json)\0*.txt;*.json";
    /// <summary>
    /// 选择文件
    /// </summary>
    /// <param name="callback">返回选择文件夹的路径</param>
    /// <param name="filter">文件类型筛选器</param>
    public static string SelectFile(string filter = VIDEOFILTER)
    {
        try
        {
            OpenFileName openFileName = new OpenFileName();
            openFileName.structSize = Marshal.SizeOf(openFileName);
            // openFileName.initialDir = "初始目录"

            openFileName.filter = filter;
            openFileName.file = new string(new char[256]);
            openFileName.maxFile = openFileName.file.Length;
            openFileName.fileTitle = new string(new char[64]);
            openFileName.maxFileTitle = openFileName.fileTitle.Length;
            openFileName.title = "选择文件";
            openFileName.flags = 0x00080000 | 0x00001000 | 0x00000800 | 0x00000008;
            if (GetSaveFileName(openFileName))
            {
                string filepath = openFileName.file; //选择的文件路径;  
                if (File.Exists(filepath))
                {
                    return filepath;
                }
            }
        }
        catch (Exception e)
        {
            Debug.LogError(e);
        }
        return null;
    }

/// <summary>
/// 选择文件夹
/// </summary>
public static string SelectFolder(string title = "选择文件夹")
{
    try
    {
        // 设置浏览对话框参数
        OpenDialogDir ofn = new OpenDialogDir();
        ofn.hwndOwner = IntPtr.Zero;
        ofn.pidlRoot = IntPtr.Zero;
        ofn.lpszTitle = title; // 对话框标题
        ofn.ulFlags = 0x00000001; // BIF_RETURNONLYFSDIRS 只返回文件系统目录
        ofn.pszDisplayName = new string(new char[260]);

        // 打开对话框
        IntPtr pidlPtr = SHBrowseForFolder(ofn);
        if (pidlPtr != IntPtr.Zero)
        {
            char[] path = new char[260];
            if (SHGetPathFromIDList(pidlPtr, path))
            {
                string folderPath = new string(path);
                folderPath = folderPath.Substring(0, folderPath.IndexOf('\0')); // 去掉结尾的空字符
                return folderPath;
            }
        }
    }
    catch (Exception e)
    {
        Debug.LogError(e);
    }
    return null;
}


    /// <summary>
    /// 选择文件
    /// </summary>
    /// <param name="callback">返回选择文件夹的路径</param>
    /// <param name="filter">文件类型筛选器</param>
    public static string SelectJsonFile(string filter = JSONFILTER)
    {
        try
        {
            OpenFileName openFileName = new OpenFileName();
            openFileName.structSize = Marshal.SizeOf(openFileName);
            // openFileName.initialDir = "初始目录"

            openFileName.filter = filter;
            openFileName.file = new string(new char[256]);
            openFileName.maxFile = openFileName.file.Length;
            openFileName.fileTitle = new string(new char[64]);
            openFileName.maxFileTitle = openFileName.fileTitle.Length;
            openFileName.title = "选择文件";
            openFileName.flags = 0x00080000 | 0x00001000 | 0x00000800 | 0x00000008;
            if (GetSaveFileName(openFileName))
            {
                string filepath = openFileName.file; //选择的文件路径;  
                if (File.Exists(filepath))
                {
                    return filepath;
                }
            }
        }
        catch (Exception e)
        {
            Debug.LogError(e);
        }
        return null;
    }
}

然后在需要调用的地方参考以下写法

 string path = FolderBrowserHelper.SelectFile();