Is there any way to start file picker for google drive in android app - to do something similar to this http://googleappsdeveloper.blogspot.com/2012/08/allowing-user-to-select-g
Yes, there is a file picker in the GDAA. The best place to see it's use is this demo, specifically the Intents section.
There are 2 methods in the demo you are interested in:
but they are essentially the same, differing only in the MIME TYPE filter specified here:
IntentSender intentSender = Drive.DriveApi.newOpenFileActivityBuilder()
.setMimeType(new String[] { DriveFolder.MIME_TYPE }) // <--- FOLDER
//.setMimeType(new String[] { "text/plain", "text/html" }) // <- TEXT FILES
.build(getGoogleApiClient());
Good Luck