Generating API Key.
Open CMD Prompt in Windows navigate to java > jre > bin and execute keytool with following parameters.


C:
cd "C:\Program Files\Java\jre\bin"
keytool.exe -list -v -alias androiddebugkey -keystore "<path_to_keystore>\debug.keystore" -storepass android -keypass android 

Mine
C:
cd "C:\Program Files\Java\jre7\bin"
keytool.exe -list -v -alias androiddebugkey -keystore "C:\Users\VeeVee\.android\debug.keystore" -storepass android -keypass android 

Copy SHA1 Certificate fingerprint



Visit >>  Google APIs Console

Wait until a popup appears, "Activate Google Maps Android API v2" you will not get a popup if you have already activated.


In the left Panel Click
--> API Access
 --> Create new Android key...
--> Paste the SHA1 key generated followed by a semicolon ';' and then your package name.


if your
SHA1 Key
AB:C0:20:F7:86:46:4C:A3:B3:A1:C9:F5:B1:EC:3B:B6:C7:1E:6F:8E

Package name
map.demo

then Enter
AB:C0:20:F7:86:46:4C:A3:B3:A1:C9:F5:B1:EC:3B:B6:C7:1E:6F:8E;map.demo



Copy the API key, use it in your App's "Manifest.xml"
Getting Started with Google MapsV2