Http://blog.sina.com.cn/s/blog_8daaa9ea0101mx7f.html
In previous versions of Android (prior to 4.1), SDcard followed the path by "/sdcard" or "/mnt/sdcard", and was modified in the jelly Bean system to "/storage/sdcard0", There may also be multiple sdcard in the future. Currently, to maintain compatibility with previous code, the SDcard path does a link mapping. To make your code more robust and compatible with future versions of Android and new devices, use Environment.getexternalstoragedirectory (). GetPath () to get the SDcard path, If you need to save a specific type of content to SDcard, consider using the Environment.getexternalstoragepublicdirectory (String type) function, which can return a specific type of directory. Currently supports the following types: directory_alarms//alarm ringtone DIRECTORY_DCIM//camera shot picture and video saved location directory_downloads//download File save location Directory_movies/ /Where the movie is saved, such as a movie downloaded via Google Play Directory_music//Where the music is saved directory_notifications///Notification tone saved location Directory_pictures// Downloaded picture saved location directory_podcasts//Used to save podcast (blog) audio file directory_ringtones//Save ringtone Location