I don’t have a definitive answer here, since I don’t use Gnome/Nautilus, but what is shown by ‘mount’ command, and how does it compare with the mount point path? (My suggestion it to post back with that info just in case it helps others to advise further.)
An interesting thread discussing similar that may (or may not) be useful
I’ve tested now with Samsung Galaxy S4 Active on three different machines now with openSUSE 13.2 and Gnome 3.14.4/Files 3.14.2.
Here is what happends;
Plugin the usb S4 beeps and from the Gnome desktop bottom line a widget popup for Samsung Android
Selecting “Open with Files” this window opens
To the left the ‘Samsung Android’ entry i listet, but the content window is blank without content.
The address field is: mtp://[usb:002,006]
I’m unsure if I have seen the content since the previous Samsung official upgrade from Android 4.2.2 to 4.4.2.
Today I downloaded and installed 905 MB Samsung update update for Android Lollipop 5.0.1, but no change.
I happended to have SLED12 and Gnome 3.10.4/Files 3.10.1 on one of these machines and there the content
Card and Phone maps are shown.
I also tested with my old Samsung Galaxy S2 with Android 4.1.2, and there the content is listed ok on all machines with openSUSE 13.2.
I tested also S4 connected using openSUSE 13.2 KDE4.14.6 and Dolphin 14.12.3
At first I got no content visible either in Dolphin, but the following message was displayed:
No Storages found. Maybe you need to unlock your device
This showed to be a very important and useful guideline that reminded and pointed me to the simple reason.
I had previously set Sreenlock ON on the S4 phone, but had no Screenlock set on my old S2.
As soon as I unlocked the S4 screenlock, the content Card and Phone were displayed, first in Dolphin and next in Gnome Files.
I also had to test again with SLED12 Gnome Files. No content on S4 (Card and Phone) was displayed before I unlocked the S4 screenlock. It had worked at the first test because I happened to connect the phone while the screenlock was open.
The solution to this stupid problem was so simple and at the same time difficult.
My suggestion is that Gnome Files should report the same useful guideline as Dolphin here