Google Maps V2 not working in production with correct key

I was having these same issues, and was banging my head against the wall for a few days. I read all the posts about putting the correct key in place. I kept putting the correct key in my google_maps_api.xml file. StKent above mentioned to make sure to overwrite with the actual string in AndroidManifest.xml. This is what fixed it for me.

What I had when it didn't work: in AndroidManifest.xml:

<meta-data
            android:name="com.google.android.geo.API_KEY"
            android:value="@string/google_maps_key" />

and in google_maps_api.xml:

 <string name="google_maps_key"
        templateMergeStrategy="preserve"
        translatable="false">AIza_the actual key</string>

What I changed to for it to work I changed my AndroidManifest.xml to include:

<meta-data
            android:name="com.google.android.geo.API_KEY"
            android:value="AIzsa_the actual key" />

When using Android Studio to generate the Google Maps Activity, it will ignore your gradle build configs and use the default debug.keystore. The SHA1 in google_maps_api.xml is based off of this default. When creating permission in the Google API console, make sure to use your production and debug SHA1 if you are using the non default.

Based on the logcat output from your debuggable release build:

01-11 16:04:54.511  19346-19437/com.mike.mapstest E/Google Maps Android API﹕ Authorization failure.  Please see https://developers.google.com/maps/documentation/android/start for how to correctly set up the map.
01-11 16:04:54.516  19346-19437/com.mike.mapstest E/Google Maps Android API﹕ In the Google Developer Console (https://console.developers.google.com)
    Ensure that the "Google Maps Android API v2" is enabled.
    Ensure that the following Android Key exists:
    API Key: YOUR_KEY_HERE
    Android Application (<cert_fingerprint>;<package_name>): <SHA1 Removed for this> ;com.mike.mapstest

it would appear that you have not overridden the api key placeholder YOUR_KEY_HERE in the manifest (or separate api keys file, depending on your configuration). Replace that string, wherever it lives, with your actual key and you should be good to go.

Edit: this tutorial, if it matches your configuration, probably explains why you are only seeing this for release builds:

Return to Android Studio and paste the API key into the YOUR_KEY_HERE section of the file:

Note that these steps have enabled Google Maps support for the debug version of the application package. The API key will also need to be added to the google_maps_api.xml file located in MapDemo -> app -> src -> release -> res -> values when the release version of the application is ready to be built.