I can't run my android maps aplication on phone

I developed an android maps application on Google API 2.1 update-1 platform. And it is the simplest code to show a map on the screen, there is no other things.

However, map doesn't shown on phone. The problem is, the same program runs on my android emulator开发者_开发百科 right but it is not working on my android phone properly, I mean program starts on phone but I see only greeds instead of map. phone android version is th same, 2.1 update-1.

Please help me, Thanks.

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If the same APK file works on the emulator but does not work on the phone, ensure that:

• The phone has a working Internet connection
• The phone's built-in Maps application works