Mobile App Integration Just For Displaying Files

Hi muratzeuz, 

Dropbox does use OAuth 2.0 to authorize access to a user's data.

When working with the Dropbox APIs, your app will access Dropbox on behalf of your users. You'll need to have each user of your app sign into dropbox.com to grant your app permission to access their data on Dropbox.

You can find everything you need to get started with the Dropbox API, including documentation, tutorials, and SDKs here:

https://www.dropbox.com/developers

Additionally, there is also a way to retrieve a refresh token to then retrieve short-lived access tokens as needed, without further manual user intervention. You can find more information in the OAuth Guide and authorization documentation. There's a basic outline of processing this flow in this blog post which may serve as a useful example.