unity 打开文件夹并选择文件

博主原创！
最近，要开发一款音乐播放软件。用unity开发，现在用到了一个功能，需要有一个按钮功能，打开windows文件夹，并选取所需要的视频，交给videoplayer进行播放。而百度上所搜到的答案，都大相近庭，更准确来说代码都是一样的，功能都是一样的，不信你可以搜索看看。大部分比较准确的答案都是切换图片，但是代码太片段话了，所以我自己整理换成我自己想要的功能。

第一个脚本，OpenFileName.cs；
//调用系统的窗口

using UnityEngine;  using System.Collections;  using System;  using System.Runtime.InteropServices;  [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 class WindowDll  {      [DllImport("Comdlg32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]      public static extern bool GetOpenFileName([In, Out] OpenFileName ofn);      public static bool GetOpenFileName1([In, Out] OpenFileName ofn)      {          return GetOpenFileName(ofn);      }  }  

第二个脚本，OpenFile.cs；
//此脚本是封装在一个类中，想要使用的话可以，可以在unity界面放到按钮的Onclick（）上；

using UnityEngine;  using System.Collections;  using System.Runtime.InteropServices;  using System.Reflection;  using UnityEngine.Video;using UnityEngine.UI;public class OpenFile : MonoBehaviour  {      public Button button;    public void OpenFileWin()    {        GameObject.FindWithTag ("moviePlayer").GetComponent<VideoPlayer> ().Pause ();        OpenFileName ofn = new OpenFileName();          ofn.structSize = Marshal.SizeOf(ofn);          ofn.filter = "All Files\0*.*\0\0";          ofn.file = new string(new char[256]);          ofn.maxFile = ofn.file.Length;          ofn.fileTitle = new string(new char[64]);          ofn.maxFileTitle = ofn.fileTitle.Length;          string path = Application.streamingAssetsPath;          path = path.Replace('/','\\');          //默认路径          ofn.initialDir = path;          //ofn.initialDir = "D:\\MyProject\\UnityOpenCV\\Assets\\StreamingAssets";          ofn.title = "Open Project";          ofn.defExt = "JPG";//显示文件的类型          //注意 一下项目不一定要全选 但是0x00000008项不要缺少          ofn.flags = 0x00080000 | 0x00001000 | 0x00000800 | 0x00000200 | 0x00000008;//OFN_EXPLORER|OFN_FILEMUSTEXIST|OFN_PATHMUSTEXIST| OFN_ALLOWMULTISELECT|OFN_NOCHANGEDIR          if (WindowDll.GetOpenFileName(ofn))          {              Debug.Log("Selected file with full path: {0}" + ofn.file);          }          //此处更改了大部分答案的协程方法，在这里是采用unity的videoplayer.url方法播放视频；        //        /*而且我认为大部分的其他答案，所给的代码并不全，所以，想要其他功能的人，可以仿照下面的代码，直接在此类中写功能。        //*/        GameObject.FindWithTag ("moviePlayer").GetComponent<VideoPlayer> ().url = ofn.file;        GameObject.FindWithTag ("moviePlayer").GetComponent<VideoPlayer> ().Play ();    }}  

按钮功能


但是，次方法有一个bug，笔者还在调试研究。当点击按钮调出file文件夹的时候，再次点击按钮会造成程序崩溃。
2017.10.12 改
bug找到解决办法，打包出来运行之后，这个问题就不存在了。问题的原因可能是选择文件的时候并不是unity自己的根目录，出现的错误提示。