I want to create a folder in the device that is visible when you on the PC's explorer navigate to the phone and open InternalStorage.
Excuse me if I am telling you something that you already know, but are you clear about the difference between what most people think of as a 'phone's "internal storage" (that is, the 'phone's memory) and what Android calls "Internal storage" (such as is used with
File.DirInternal)?
Files and directories written using
File.DirInternal etc are internal to the app; they are not accessible to other apps and certainly not to an attached PC. But if you use
File.DirExternal then the files are written in the public area of the 'phone memory. Some people think that
File.DirExternal refers to something like an SD card, but that is not the case. If you write folders using
File.DirExternal then they will be accessible to a PC.
There is another complication that can happen. Sometimes when you hook up to a PC the devices create an MTP connection (Media Transfer Protocol) and this prevents you seeing the 'phone memory at all. I think that this depends on the driver in the PC. If this is the problem then you have to find a way to connect your 'phone for file transfer. The way to do this varies from 'phone to 'phone and can be a real nuisance.
Again, I am sorry if you already understand this, but it confused me for a while.