创建一个返回false的none case,当3D touch开始时调用该case,当3D touch结束时调用select case。
override public func canPerformAction(_ action: Selector, withSender sender: Any?) -> Bool
{
switch self.currentState {
case .select:
if action == #selector(select(_:)) || action == #selector(selectAll(_:))
{
return true
}
case .copy:
if action == #selector(copy(_:))
{
return true
}
case .paste:
if action == #selector(paste(_:)) || action == #selector(select(_:)) || action == #selector(selectAll(_:))
{
return true
}
case .none:
return false
}
return false
}