I'm not sure how you plan to create your user interface to open the file. I used several different ways, so I will express some ideas. UITableView is ideal for large file sizes. The general view of scrolling can also be used for a large number of files. I used a warning view for an application that only generates one or two files. You can also use the presentation with document icons, such as the iPad Mail app. To get document icons, use the UIDocumentInteractionController . The WWDC 2010 DocInteraction sample code has great depth using the UIDocumentInteractionController .
As for opening a file, the Quick Look function simplifies the search process. A simple standalone solution is to subclass QLPreviewController . Then your subclass must conform to the QLPreviewControllerDataSource protocol and, if necessary, the QLPreviewControllerDelegate protocol. Then pass in an NSURL array pointing to your files. You can do this either through the initializer, for example, -initWithFiles:(NSArray *)files , or through the setter. From here -previewController:previewItemAtIndex: just need to be indexed into an array to display the corresponding file. -numberOfPreviewItemsInPreviewController: just need to return the size of the array. Once you finish this class, you can use any user interface design that you like to click on this view or present it in different ways.
Hope this is more understandable than my tutorial you read.
EDIT:
I posted some code on Github that might help you. I created a preview file class as described above. I also posted a demo application that directly uses QLPreviewController .