我想在iPad上使用UIDocumentInteractionController，请问怎么使用啊？

[shaoniantingyu_hj]

我想在iPad上使用UIDocumentInteractionController，iPhone 上可以直接用，iPad上好像不可以请问怎么使用？

? ?NSURL *imageURL=[NSURL fileURLWithPath:saveImagePath];
self.documentController=[[UIDocumentInteractionController alloc]init];
self.documentController = [UIDocumentInteractionController interactionControllerWithURL:imageURL];
self.documentController.delegate = self;
self.documentController.annotation = [NSDictionary dictionaryWithObjectsAndKeys:[NSString stringWithFormat:@"Testing"], @"InstagramCaption", nil];
self.documentController.UTI = @"com.instagram.exclusivegram";
UIPopoverController *popover=[[UIPopoverController alloc]initWithContentViewController:_documentController];

? ? [popover presentPopoverFromRect:CGRectMake(SCREEN_WIDTH * 0.6, SCREEN_HEIGHT * 0.95, SCREEN_WIDTH / 2,SCREEN_HEIGHT * 3 /2) inView:self.view permittedArrowDirections:UIPopoverArrowDirectionDown animated:YES];
?

[shaoniantingyu_hj]

别沉，求大神出来教我一下