facebook authorization dialog style

in Facebook official website, iphone authorization dialog is

while when I work follow its steps(iOS for iPhone/i开发者_开发百科Pad): http://developers.facebook.com/docs/guides/mobile/ I got the authorization dialog as follows which is the same as Mobile Web.

Who can tell me why? How can I get authorization dialog as the iphone one in Facebook official website?

On the latest versions of iOS on the device and if Facebook app is installed on the device there will be login dialog. If Facebook app is not installed, then it will open Safari to obtain the access token. This is by design of Facebook iOS SDK. You can patch the SDK if you don't want Safari in in any case.

see authorizeWithFBAppAuth method in Facebook.m

hope this helps