I've got new LG G4 and I've tried all these steps:
*connected my phone with usb.
*installed abd LG G4 driver.
*usb is on PTP mode.
*I've set my G4 to developers mode.
And my Android Studio is still not recognizing my G4. My laptop is recognizing it. I can import photos, music and everything. It is only the android studio which isn't recognizing it.
In the developer options have you set USB debugging on? This might be obvious but you haven't added this information so maybe this might help.