注意要在跳转的控制器中重写previewActionItems
override var previewActionItems: [UIPreviewActionItem] {
let item1 = UIPreviewAction(title: "sure", style: .default) { (_, _) in
}
let item2 = UIPreviewAction(title: "cancel", style: .destructive) { (_, _) in
}
return [item1,item2]
}