首先 必须用 customView 初始化 item it
customView 必须实现 UIGestureRecognizerDelegate 协议io
var leftItem = UIBarButtonItem(customView: customView)协议
而后 添加self.navigationController!.interactivePopGestureRecognizer.delegate = customViewdi
酱紫 就能够拖动返回了vi
肿么样造了吧co