Iphone 如何在ios应用程序中显示pdf？

有人能告诉我如何在ios应用程序上显示pdf吗？

我试过这个，从其中一个问题中得到了这个答案

NSMutableDictionary * paramms = [NSMutableDictionary dictionaryWithObjectsAndKeys:
                                @"select uid,name,birthday_date from user where uid in (select uid2 from friend where uid1=me())", @"query",
                                nil];
[[StaticFacebook getFacebook] requestWithMethodName: @"fql.query" 
                       andParams: paramms
                   andHttpMethod: @"POST" 
                     andDelegate: self];