I’m using Android Studio and logcat shows no output; it just says “no connected devices” and “no debuggable applications” (see picture below).
I know that this sounds like a duplicate, but I’ve tried answers from other questions (e.g. Android Studio – no debuggable applications) and it didn’t help: I enabled ADB Integration, set the debuggable flag in the gradle file, closed Eclipse and restarted both Android Studio and my computer a few times.
You can try restarting the adb server as root.
sudo adb kill-server && sudo adb start-server