Android Studio recognizes physical Device as Null?
Just run this command after you connect your device to your Ubuntu system:
adb devices
This works for me.
Note: Make sure you have selected file transfer option in your phone.
Ok So I finally found the problem, apparently on this device you have to set to connect as camera(even after usb debugging is already enabled)
Also this link describes the setting up process
I've seen this error a few times when adb hasn't been connected with correct permissions.
On the terminal try
~/Android/Sdk/platform-tools> ./adb devices
if it returns
<deviceIdentifier> no permissions
then you need to restart adb with correct perms
~/Android/Sdk/platform-tools$> ./adb kill-server
~/Android/Sdk/platform-tools$> sudo ./adb devices
if that worked then you'll get
List of devices attached
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
<deviceIdentifier> device
No more Sdk version resolution issues in Android Studio after that.