No directories on android 6.0.1

Currently I am testing with different devices and different android versions. There seems to be a bug in the android version 6.0.1. If I open the file-chooser dialog, there are no folders shown in the list. the directory path is also empty. (see attached picture)
Would be great if this would get fixed soon. thanks :)

[Ahmed--Kamal]

You have to ask user for permission at runtime.
follow below links for solution:

• http://stackoverflow.com/questions/32175770/android-m-user-permission-error-read-and-write
• http://stackoverflow.com/questions/33162152/storage-permission-error-in-marshmallow