If you tried to run your app on your Android device, but the device wasn’t listed (although you have your USB drivers installed and Developer options enabled on your device), be sure to enable the “USB debugging” option in Developer options.
If you don’t do that before you plug in your phone to the computer over USB, your Android device won’t be listed in available devices when you try to run your app.
On most devices running Android 3.2 or older, you can find the option under Settings > Applications > Development. On Android 4.0 and newer, it’s in Settings > Developer options. Note: On Android 4.2 and newer, Developer options is hidden by default. To make it available, go to Settings > About phone and tap Build number seven times. Return to the previous screen to find Developer options.
from the toolbar. In the Choose Device window that appears, select the Choose a running device radio button, select your device, and click OK .