Help us understand the problem. What is going on with this article?

現在表示されているViewControllerを取得する方法

背景

iOSアプリ向けのSDKを開発する場合、アプリの画面上にポップアップやダイアログ等のViewを表示したい場合があります。その場合、現在表示されているViewControllerにviewをaddSubViewする方法が考えられますが、SDK開発の場合はアプリ側の実装を知ることができないため、ViewControllerにアクセスするためにやや特殊な手法を用いる必要があります。

手法

下記のようにUIApplicationからrootViewControllerにアクセスすることで、現在表示されているViewControllerを取得することができます。

func getTopViewController() -> UIViewController? {
    if let rootViewController = UIApplication.shared.keyWindow?.rootViewController {
        var topViewController: UIViewController = rootViewController

        while let presentedViewController = topViewController.presentedViewController {
            topViewController = presentedViewController
        }

        return topViewController
    } else {
        return nil
    }
}

ViewControllerを取得したら、下記のようにaddSubViewすることで画面上に任意のViewを表示させることができるでしょう。

if let topViewController: UIViewController = getTopViewController() {
    topViewController.view.addSubview(customView)
}
Why do not you register as a user and use Qiita more conveniently?
  1. We will deliver articles that match you
    By following users and tags, you can catch up information on technical fields that you are interested in as a whole
  2. you can read useful information later efficiently
    By "stocking" the articles you like, you can search right away
Comments
Sign up for free and join this conversation.
If you already have a Qiita account
Why do not you register as a user and use Qiita more conveniently?
You need to log in to use this function. Qiita can be used more conveniently after logging in.
You seem to be reading articles frequently this month. Qiita can be used more conveniently after logging in.
  1. We will deliver articles that match you
    By following users and tags, you can catch up information on technical fields that you are interested in as a whole
  2. you can read useful information later efficiently
    By "stocking" the articles you like, you can search right away