Google MapView doesn't work after signed the app

I am facing to android application signing problem. My application contains Google MapView. When I compile the app and run on the emulator, MapView works fine. But signed the app, MapView doesn't work. I've get Google Map API. This works on the simulator.

I could sign the app once 2 months ago. Then I've upgraded the app. Now I need to sign the app again. Actually I don't know why signed app's mapView doesn't work. How to fix it ?

Please advice.

I used following steps when sign the app:

1. Run Eclipse.
2. Select the project. Right Click -> Android Tools -> Export Signed Application Package -> Then Filled forms. (In forms, Validity years: 200, 开发者_运维知识库and all passwords are same.)

Can you suggest me ?

Thanks in advance.

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yes wen u sign the app u need to create another key for the MapView... This key is generated by google wen u provide the MD5 fingerprint of the key u used for signing and replace the older key u must have provided at design time in the xml...