I want to pass access token for get the list of files from google drive.

What I have done :

1. Register app to Google dev console.
2. I have client id based on OAuth 2.0

What i want to do :

1. Call `HttpCall` for `https://www.googleapis.com/drive/v2/files`
2. I want to set access token in header like this :

`DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost post = new HttpPost("https://www.googleapis.com/drive/v2/files");
post.addHeader("Content-Type", "application/json");
post.addHeader("Authorization","Bearer XXXXXXXXXXXXXXXXXXXXXXXXX");`
3. How can I get access token for Authorization by using `OAuth2.0` Client Id