android google map view

This is the problem of Wrong map key.

You have to find your debug.keystore file path and then you have to generate google map key.

              In windows: 
              The debug.keystore is mostly found at :
              C:\Users\UserName\.android\debug.keystore

              Same is in ubuntu, means in home\user\username\.android\debug.keystore

              For conveniency: 
              You can download the "Keytool plugin" in android to get the md5 fingerprint.

              After getting md5 fingerprint, You can obtain the map key from here:

              https://developers.google.com/android/maps-api-signup

I had the same problem before, the question is that when we compile the app and get the release apk, google actually thinks that the app is released, so we have to get a release key to use it on real devices, but for a while to keep testing and developing the app, we should use the debug apk. To use the debug apk just go to:

YourApplicationFolder\app\build\outputs\apk\app-debug.apk

After compile or running on emulator.

Make it as a signed application and uninstall the previous application, then install it again. This will work as I faced the same problem.

I think you have used the debug key(for generating the unique key). Try to use release key instead. Use the following command:

keytool -list -keystore fileName.keystore

on command prompt to generate the release key. For more details see http://code.google.com/android/add-ons/google-apis/mapkey.html.

Hope this will work for you.