I have attached a mapview to my layout and have a it showing a compass and my current location. The problem I have is, that there is no street map shown in the view, so basically I just see the compass and my current location over a blank grid.
When you run or debug through Eclipse your app is signed with your debug key which will have been automatically created. It is not the same as the key you sign your app with when releasing it.
You need to get an API key using your debug key.
See the 'Getting the MD5 Fingerprint of the SDK Debug Certificate' section on http://code.google.com/android/add-ons/google-apis/mapkey.html
Once you are ready to release your app, you replace the debug API key with the API key you are currently using.
Make sure you have the INTERNET permission and a proper API key. Either of those will give you the blank grid effect.
http://code.google.com/android/add-ons/google-apis/mapkey.html
Turns out the map is only shown when the app is signed and uploaded using adb install {path to app}, the same app didn't work when I run or debug using Eclipse.
Check out the followings: 1. include jar of maps. 2. generate your certificate and register it. It should work now :)
来源：https://stackoverflow.com/questions/1097594/how-to-show-a-map-in-an-android-mapactivity