How to open file in specified app in iOS?

I know the UIWebview,UIDocumentInteractionController,QLPreviewController can do the fileview work of office files, i want to view the office file in a better way the

[self.docInteractionController presentOptionsMenuFromRect:self.view.frame  inView:self.view animated:YES];

can show all apps can open the file , how can i choose the specified one automatically