Swift 中显示 UIAlertcontroller 时保持键盘打开？

Question

当警报弹出时，键盘被关闭。我到处都看过，但没有找到保持键盘可见的解决方案。当出现警报时，文本字段似乎会自动退出第一响应者，因为警报是模态出现的。怎样才能让键盘保持在这个警报后面，这意味着即使无法进行交互，文本字段仍在编辑？

Answer 1

这个解决方案适合我：

let rootViewController: UIViewController = 
    UIApplication.sharedApplication().windows.lastObject.rootViewController!!
rootViewController.presentViewController(alert, animated: true, completion: nil)

@galambalazs 编辑： 它起作用的原因是：

您可以获取当前最高 window 级别的 window 并在 [=34= 中展示您的 View Controller ]（使其成为顶部View Controller中的顶部Window）。

UIApplication.sharedApplication().windows
The windows in the array are ordered from back to front by window level;
thus, the last window in the array is on top of all other app windows.

您可能还想设置 window 的 tintColor，使其与您的应用程序的全局 tintColor 相匹配。

UIWindow *topWindow = [UIApplication sharedApplication].windows.lastObject;
// we inherit the main window's tintColor because topWindow may not have the same
topWindow.tintColor = [UIApplication sharedApplication].delegate.window.tintColor;

Answer 2

For Swift 3 and iOS11

if let alertWindow = UIApplication.shared.windows.last, alertWindow.windowLevel == 10000001.0 // If keyboard is open
  { // Make sure keyboard is open
    alertWindow.rootViewController?.present(alertController, animated: true, completion: nil)
  }
  else
  {
    viewController?.present(alertController, animated: true, completion: nil)
  }

Swift 中显示 UIAlertcontroller 时保持键盘打开？

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