adb not detecting your Android Device ?

To debug your mobile application on an actual device, Android requires you to connect your device to your computer and test if it is detectable by Android.

To achieve that , you need to go to -

<android-install-location>/sdk/platform-tools 

and give the command

adb devices

You might not have platform-tools  installed by default.

So install it through the SDK Manager before you read further.

Ideally the output of  the command should be the serial number of your device.

But many times if the device is not read by Android you end up seeing blank.

To troubleshoot , make sure that -

1.  USB debugging is enabled on your Android phone
2.  Ensure that you have successfully downloaded and installed Google USB Driver Package
3.  In case of Samsung devices,install Samsung Kies as it installs device drivers.
4. Goto Control Panel->System ->Device Manager and make sure that none of the drivers show any error.

For Samsung devices Samsung Kies software installs device drivers.

There are different Kies versions for different Samsung devices so make sure you have installed the right Kies

Eg:  Kies 2 supports Samsung Note 2 but Kies 3 doesnt.
If you try to connect a Samsung Note 2 with Kies 3 installed,you will observe device driver errors.
You will then have to install Kies 2