Creating an Android OAuth 2.0 client using the Implicit grant type with the system browser

The specification for OAuth 2.0, which is RFC 6749, address native mobile applications with just a small section. It does not states which grant type must be used or not, although it mentions the usage of Authorization Code and Implicit grant type. The only concern when using Implicit grant type is about that a refresh token is not returned requiring the authorization processes once the access token expires. Even though, the most recent specification, OAuth 2.0 for native apps (RFC 8252) states that implicit flow isn't recommended for native apps, basically because by using this grant type the client application will not be able to use PKCE, which avoids interception attacks (we will see more about PKCE in the Protecting an Android client with PKCE recipe).

Despite these considerations, this recipe still presents you with how to use the Implicit grant type, because depending on your scenario, you might...