Restful Web Service Using Oauth For Mobile Application

I am building an application that consists of two main parts: Web application with rest API. Mobile application(android, iPhone). The Web application has a database that stores

Solution 1:

After some further research and talking with some of my colleagues I decided that the best option to go for is Second idea. I decided to handle redirects using WebView (which exists both on iPhone and Android). WebView I will configure in such way that it automatically exits when user is redirected back to specific URL on web app that returns JSON.
I decided this to be the best idea because this way I only have to implement/configure WebView on mobile app while all oAuth logic is done on web app which means there is less code repetition among mobile apps (android, iPhone) and it is more extendible (I have to modify one web app, not 2 or 3 mobile apps).