如何呈现UICollectionViewController？

Question

我收到一个错误：

致命错误：在展开Optional值时意外发现nil

didTapUserScreenButton()工作正常，didTapChatControllerButton()给出了错误。我认为它可能会得到错误，因为didTapChatControllerButton()进入UiCollectionViewController?而另一个正常，因为它将进入UITableViewController?。

func didTapChatControllerButton() {
    let chat_log_controller = ChatLogController
    let navController = UINavigationController(rootViewController: chat_log_controller!)
    present(navController, animated: true, completion: nil)

}


func didTapUserScreenButton() {
    let user_screen_vc = usersScreenVC()
    let navController = UINavigationController(rootViewController: user_screen_vc)
    present(navController, animated: true, completion: nil)

Answer 1

您错过了（当前为空）初始化参数持有者括号。尝试使用tris：

let chat_log_controller = ChatLogController()
let navController = UINavigationController(rootViewController: chat_log_controller)
present(navController, animated: true, completion: nil)