I tried following a tutorial on Android Maps V2 Quick Start But when I run the app, a blank map screen is shown. My phone uses android 2.2.1.
I finally found out what the problem was. I was picking the wrong debug keystore. I am working with an ubuntu machine. Since I opened eclipse as root, the default keystore in eclipse was located in my root folder(/root/.android/.android/debug.keystore) whiles I was creating the api key with the debug keystore from my user folder. I created a new api key with the debug keystore in the root folder and it works now.