如何消除 UIAlertController 的延迟？

Question

点击 table 个单元格后，警报视图显示有 4 到 5 秒的延迟。下面是代码

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath){

let cell = tableView.cellForRow(at: indexPath)!
let alertController = UIAlertController(title: nil, message: nil, preferredStyle: .alert)

let ok = UIAlertAction(title: "Ok", style: .default, handler: { (action) -> Void in
    let cell = tableView.cellForRow(at: indexPath)!
    })
let cancel = UIAlertAction(title: "Cancel", style: .cancel, handler: { (action) -> Void in
})
   alertController.addAction(ok)
   alertController.addAction(cancel)

present(alertController, animated: true, completion: nil)
}

如何避免这种延迟？

Answer 1

在主队列中编写代码以呈现 UIAlertViewController。

DispatchQueue.main.async {
   //Write your code here.
}

Answer 2

当我们处理 UI 时，重要的是必须在 main tread 上完成。所以只需复制显示警报的代码并粘贴到调度主线程块中。

DispatchQueue.main.async {
   let alertController = UIAlertController(title: nil, message: nil, preferredStyle: .alert)

let ok = UIAlertAction(title: "Ok", style: .default, handler: { (action) -> Void in
    let cell = tableView.cellForRow(at: indexPath)!
    })
let cancel = UIAlertAction(title: "Cancel", style: .cancel, handler: { (action) -> Void in
})
   alertController.addAction(ok)
   alertController.addAction(cancel)

present(alertController, animated: true, completion: nil)
}

如何消除 UIAlertController 的延迟？

How to remove delay from UIAlertController?

uitableview

ios

swift

uialertcontroller