http://tech.ddvip.com/2013-02/1359737407190064.html

Streaming Assets

Most assets in Unity are combined into the project when it is built. However, it is sometimes useful to place files into the normal filesystem on the target machine to make them accessible via a pathname. An example of this is the deployment of a movie file on iOS devices; the original movie file must be available from a location in the filesystem to be played by the PlayMovie function.

Unity中的资源在编译过程中会被编译到工程项目中。有时候把这些文件放在目标机的文件系统中通过文件路径访问更有用。在iOS设备上开发影视文件就是一例，原始影视文件必须可以被能PlayMovie函数通过文件系统访问的到。

Any files placed in a folder called StreamingAssets in a Unity project will be copied verbatim to a particular folder on the target machine. On a desktop computer (Mac OS or Windows) the location of the files can be obtained with the following code:-

Unity工程中StreaminggAsset文件夹中的所有文件都不被逐字节的被拷贝到目标机的特定文件夹。在桌面电脑（Mac OS 或者Windows系统中）。这个特定文件夹可以通过

  path = = Application.dataPath + "/StreamingAssets";

path = = Application.dataPath + "/StreamingAssets";来访问

On iOS, you should use:-

  path = Application.dataPath + "/Raw";

...while on Android, you should use:-

  path = "jar:file://" + Application.dataPath + "!/assets/";

Note that on Android, the files are contained within a compressed .jar file (which is essentially the same format as standard zip-compressed files). This means that if you do not use Unity's WWW class to retrieve the file then you will need to use additional software to see inside the .jar archive and obtain the file.

请注意在Android中，这些文件被打包成一个.jar形式（也是标准的zip格式文件）的压缩包。这意味着如果你不使用Unity的WWW类来获取文件，就必须要用额外的软件来打开.jar文件并获取资源