在目标 c iOS 中获取顶部可见视图控制器答案

【问题标题】：get top visible view controller in objective c iOS在目标 c iOS 中获取顶部可见视图控制器
【发布时间】：2018-06-13 03:03:45
【问题描述】：

我正在实现这个方法，但它总是返回我的 rootviewcontroller，而不是当前的可见控制器，我怎样才能找到一个可见的控制器。我也关注这个链接。 iPhone -- How to find topmost view controller。但同样的问题呢。

    + (UIViewController *)visibleViewController:(UIViewController *)rootViewController
{
    if (rootViewController.presentedViewController == nil)
    {
        return rootViewController;
    }
    if ([rootViewController.presentedViewController isKindOfClass:[UINavigationController class]])
    {
        UINavigationController *navigationController = (UINavigationController *)rootViewController.presentedViewController;
        UIViewController *lastViewController = [[navigationController viewControllers] lastObject];

        return [self visibleViewController:lastViewController];
    }
    if ([rootViewController.presentedViewController isKindOfClass:[UITabBarController class]])
    {
        UITabBarController *tabBarController = (UITabBarController *)rootViewController.presentedViewController;
        UIViewController *selectedViewController = tabBarController.selectedViewController;

        return [self visibleViewController:selectedViewController];
    }

    UIViewController *presentedViewController = (UIViewController *)rootViewController.presentedViewController;

    return [self visibleViewController:presentedViewController];
}

【问题讨论】：

标签： ios objective-c iphone uiviewcontroller

【解决方案1】：

我认为问题出在您的功能上。可能是您的根视图控制器不正确。尝试实现以下功能，看看它是否适合您：

+ (UIViewController*) topMostController
{
    UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;

    while (topController.presentedViewController) {
        topController = topController.presentedViewController;
    }

    return topController;
}

【讨论】：

它返回给我 rootview 控制器
它总是返回我作为 rootviewcontroller 的 slideNavigationController。不是我当前的视图控制器
奇怪！！你能告诉我你的故事板吗？你是如何连接它的，那么你是如何呈现顶视图的？

【解决方案2】：

客观C

+ (UIViewController*) topMostController { // top most ViewController
    UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;

    while (topController.presentedViewController) {
        topController = topController.presentedViewController;
    }

    return topController;
}

Swift3.0

extension UIApplication {
  func topMostViewController() -> UIViewController? { // top most ViewController
    return self.keyWindow?.rootViewController?.topMostViewController()
   }
}

// Find top most ViewController in Appdelegate
let topController = UIApplication.shared.topMostViewController()

【讨论】：

它返回给我 rootview 控制器
转到下一个 ViewController 并检查它

【解决方案3】：

我认为你的逻辑不太正确。试试：

+(UIViewController*)topMostController
{
    return [[self class] visibleControllerForController:[UIApplication sharedApplication].keyWindow.rootViewController];
}

+(UIViewController*)visibleControllerForController:(UIViewController*)controller
{
    // Determine last controller in navigation stack
    UIViewController *topViewController = controller;
    if ([controller isKindOfClass:[UITabBarController class]]) {
        topViewController = ((UITabBarController*)controller).selectedViewController;
    }
    if ([controller isKindOfClass:[UINavigationController class]]) {
        topViewController = ((UINavigationController*)controller).topViewController;
    } else if (controller.navigationController) {
        topViewController = controller.navigationController.topViewController;
    }

    // If last controller is presenting a modal recurse - find the last controller in that navigation stack
    UIViewController *presentedViewController = topViewController.presentedViewController;
    if (presentedViewController && ! presentedViewController.isBeingDismissed) {
        return [[self class] visibleControllerForController:presentedViewController];
    }

    return topViewController;
}

【讨论】：

【解决方案4】：

最后我通过添加更多代码解决了这个问题。像这样……

UINavigationController *vc = SharedAppDelegate.navigationController;
    NSLog(@"%@",vc.viewControllers);
    UIViewController* controller = vc.viewControllers.firstObject;
    NSLog(@"%@",controller.childViewControllers);
    UIViewController* carbonContr = controller.childViewControllers.firstObject;

【讨论】：