<UITextFieldDelegate,UIDocumentInteractionControllerDelegate> 协议代理
@property (nonatomic,strong) UIDocumentInteractionController *udic; 属性

-(void)accept:(UITapGestureRecognizer *)tap{

NSLog(@"同意用户协议");

NSURL *url = [[NSBundle mainBundle]URLForResource:@"许可使用协议" withExtension:@"pdf"];
NSLog(@"%@",url);
[self presentUDIC:url];

}

• (UIViewController *)documentInteractionControllerViewControllerForPreview:(UIDocumentInteractionController *)controller
  {
  return self;
  }

• (void)presentUDIC:(NSURL *)url
  {
  if(url){
  self.udic = [UIDocumentInteractionController interactionControllerWithURL:url];
  self.udic.delegate = self;
  [self.udic presentPreviewAnimated:YES];
  [self.udic presentOpenInMenuFromRect:self.view.frame inView:self.view animated:YES];
  }
  }