对于超全屏或超上下文模式表示，“is visible”可能意味着它在视图控制器堆栈的顶部，或者只是可见，但被另一个视图控制器覆盖。

要检查视图控制器“is the top view controller”和“is visible”是否有很大不同，你应该检查视图控制器的导航控制器的视图控制器堆栈。

我写了一段代码来解决这个问题:

extension UIViewController {
    public var isVisible: Bool {
        if isViewLoaded {
            return view.window != nil
        }
        return false
    }

    public var isTopViewController: Bool {
        if self.navigationController != nil {
            return self.navigationController?.visibleViewController === self
        } else if self.tabBarController != nil {
            return self.tabBarController?.selectedViewController == self && self.presentedViewController == nil
        } else {
            return self.presentedViewController == nil && self.isVisible
        }
    }
}

上述解决方案存在几个问题。如果你正在使用，例如，一个UISplitViewController，主视图总是会返回true

if(viewController.isViewLoaded && viewController.view.window) {
    //Always true for master view in split view controller
}

相反，采用这种简单的方法似乎在大多数情况下都很有效，如果不是所有情况:

- (void)viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear:animated];

    //We are now invisible
    self.visible = false;
}

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];

    //We are now visible
    self.visible = true;
}

对于那些正在寻找Swift 2.2版本的答案的人:

if self.isViewLoaded() && (self.view.window != nil) {
     // viewController is visible
}

Swift 3:

if self.isViewLoaded && (self.view.window != nil) {
         // viewController is visible
}

我需要这个来检查是否视图控制器是当前的视图控制器，我通过检查是否有任何呈现的视图控制器或通过导航器推送，我张贴它以防有人需要这样的解决方案:

if presentedViewController != nil || navigationController?.topViewController != self {
      //Viewcontroller isn't viewed
}else{
     // Now your viewcontroller is being viewed 
}

我在uiviewcontroller。h中找到了这些函数。

/*
  These four methods can be used in a view controller's appearance callbacks to determine if it is being
  presented, dismissed, or added or removed as a child view controller. For example, a view controller can
  check if it is disappearing because it was dismissed or popped by asking itself in its viewWillDisappear:
  method by checking the expression ([self isBeingDismissed] || [self isMovingFromParentViewController]).
*/

- (BOOL)isBeingPresented NS_AVAILABLE_IOS(5_0);
- (BOOL)isBeingDismissed NS_AVAILABLE_IOS(5_0);

- (BOOL)isMovingToParentViewController NS_AVAILABLE_IOS(5_0);
- (BOOL)isMovingFromParentViewController NS_AVAILABLE_IOS(5_0);

也许上面的函数可以检测ViewController是否出现。

我根据@ program的回答做了一个快速扩展。

它允许你很容易地检查UIViewController是否在屏幕上，就像这样:

if someViewController.isOnScreen {
    // Do stuff here
}

扩展:

//
//  UIViewControllerExtension.swift
//

import UIKit

extension UIViewController{
    var isOnScreen: Bool{
        return self.isViewLoaded() && view.window != nil
    }
}