Run the ApiDemos sample app
Once your app is delivered to customers, custom styles for maps with map IDs can be updated from Google Cloud Console. The new styles will be reflected in your app in a few hours.
To make sure new custom styles show up immediately for testing purposes, clear app data from your test device. For more information on clearing data from your device, see Android Help - Free Up Space.
Note that settings can vary by phone. For more information, contact your device manufacturer.