get Root directory (i.e external or external sdcard) from file path

问题

I am facing a situation to calculate the free size of the currently selected primary memory(i.e external or external sdcard). All i have is the file path in app specific folder like below

"/root/extsdcard/Android/data/com.a.b/files/img0001.jpg";

or

"/root/ext/Android/data/com.a.b/files/img0001.jpg";

How i can get the path "/root/extsdcard/" or "/root/ext/" respectively from above shown paths?

回答1:

Just mention "/" for root directory e.g. File

File f=new File("/");

String files[]=   f.list(); 

来源：https://stackoverflow.com/questions/38381871/get-root-directory-i-e-external-or-external-sdcard-from-file-path