当用户尝试在iOS中打开电子邮件附件时，如何显示“打开方式...”

I've seen some iOS apps have this function: When a user tries to open an email attachment, they can press and hold on the attachment for a couple of seconds, and a popup menu will appear displaying two buttons. One button reads "Open in iBooks" (for example). When user clicks it, then the app will be run and open the attachment.I've seen some iOS apps have this function: Whe