PlacePicker.IntentBuilder closes immediately after opening

I was having the same issue. Make sure you enable "Places API for Android" and not just "Places API" in the Developer Console. "Places API for Android" will not show up under "APIs & Auth/APIs" because it isnt a popular API (yet). You will have to search for it using the API search box.

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

Make sure have have you define in manifest file.

Go through those:

1. Check Google developer console to check is the "Place SDK for Android" is enabled
2. Add credentials for the enabled API. Use your package name and SHA1 key.
3. Check AndroidManifest file for, is added API key and meta tags and permissions

Try changing com.google.android.maps.v2.API_KEY to com.google.android.geo.API_KEY in the AndroidManifest.xml.

Here is a link to more information.