I want to test my App in a Samsung Galaxy S4, i've checked "unknown sources" and enabled the developer menu and checked "Debug mode". But It is displayed offline
C:\Program Files (x86)\Android\android-sdk\platform-tools>adb.exe devices
List of devices attached
XXXXXXXX offline
any ideas why?
Check that you have latest Android SDK tools. After installing latest SDK tools, check your phone: you need to confirm that you allow debugging from your computer.