获取 iOS Swift 中的所有 UIViewController 列表

Question

有什么方法可以获取 iOS Swift 项目中的所有 UIViewControllers。我想获取所有 UIViewControllers 的数组并检查特定的 UIViewController 是否存在。我必须在项目中找到特定的 UIViewController 是否存在。

Answer 1

你可以用下面的代码来做。

let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate

if let viewControllers = appDelegate.window?.rootViewController?.presentedViewController
{
    // Array of all viewcontroller even after presented
}
else if let viewControllers = appDelegate.window?.rootViewController?.childViewControllers
{
    // Array of all viewcontroller after push                            
}

Swift 4.2 (XCode 10)

let appDelegate = UIApplication.shared.delegate as! AppDelegate

if (appDelegate.window?.rootViewController?.presentedViewController) != nil
{
    // Array of all viewcontroller even after presented
}
else if (appDelegate.window?.rootViewController?.children) != nil
{
    // Array of all viewcontroller after push
}

Answer 2

这是我根据上一个答案所做的扩展

使用泛型 + 扩展 (?Swift 5.1)

/**
 * - Returns: ViewController of a class Kind
 * ## Examples: 
 * UIView.vc(vcKind: CustomViewController.self) // ref to an instance of CustomViewController
 */
 public static func vc<T: UIViewController>(vcKind: T.Type? = nil) -> T? {
     guard let appDelegate = UIApplication.shared.delegate, let window = appDelegate.window else { return nil }
     if let vc = window?.rootViewController as? T {
         return vc
     } else if let vc = window?.rootViewController?.presentedViewController as? T {
         return vc
     } else if let vc = window?.rootViewController?.children {
         return vc.lazy.compactMap { $0 as? T }.first
     }
     return nil
 }