ios - 获取对 iOS 中顶级视图控制器的引用

Question

如何在我的应用程序中获取对顶部可见视图控制器的引用。我看到了一些使用 navigationcontroller.[top|visible]viewcontroller 的解决方案。但我不在我的应用程序中使用导航控制器。

这似乎是一个很常见的用例，我发现很难访问 top|visible 视图控制器很奇怪

Answer 1

这也应该遵循您的模态视图和导航控制器（如果有）：

- (UIViewController *)deepestPresentedViewControllerOf:(UIViewController *)viewController
{
    if (viewController.presentedViewController) {
        return [self deepestPresentedViewControllerOf:viewController.presentedViewController];
    } else {
        return viewController;
    }
}

- (UIViewController *)topViewController
{
    UIViewController *rootViewController = [[[UIApplication sharedApplication] keyWindow] rootViewController];
    UIViewController *deepestPresentedViewController = [self deepestPresentedViewControllerOf:rootViewController];
    if ([deepestPresentedViewController isKindOfClass:[UINavigationController class]]) {
        return ((UINavigationController *)deepestPresentedViewController).topViewController;
    } else {
        return deepestPresentedViewController;
    }
}

Answer 2

您可能应该在这里使用委托模式（为子视图控制器提供对其可以调用的对象的引用）。如果您编辑帖子以解释为什么您认为需要对顶视图控制器的引用，我们可以为您提供有关如何在您的情况下使用委托模式的建议。

但现在我只会给你绳子，你需要吊死自己：

UIViewController *topVC = [UIApplication sharedApplication].keyWindow.rootViewController;

Answer 3

-(UIViewController *) getTopMostController
{
    UIWindow *topWindow = [UIApplication sharedApplication].keyWindow;
    if (topWindow.windowLevel != UIWindowLevelNormal)
    {
        topWindow = [self returnWindowWithWindowLevelNormal];
    }

    UIViewController *topController = topWindow.rootViewController;
    if(topController == nil)
    {
        topWindow = [UIApplication sharedApplication].delegate.window;
        if (topWindow.windowLevel != UIWindowLevelNormal)
        {
            topWindow = [self returnWindowWithWindowLevelNormal];
        }
        topController = topWindow.rootViewController;
    }

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

    if([topController isKindOfClass:[UINavigationController class]])
    {
        UINavigationController *nav = (UINavigationController*)topController;
        topController = [nav.viewControllers lastObject];

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

    return topController;
}

-(UIWindow *) returnWindowWithWindowLevelNormal
{
    NSArray *windows = [UIApplication sharedApplication].windows;
    for(UIWindow *topWindow in windows)
    {
        if (topWindow.windowLevel == UIWindowLevelNormal)
            return topWindow;
    }
    return [UIApplication sharedApplication].keyWindow;
}

Answer 4

-(UIViewController *)getCurrentViewController
{
    UIViewController *result = nil;
    UIWindow * window = [[UIApplication sharedApplication] keyWindow];
    if (window.windowLevel != UIWindowLevelNormal)
    {
        NSArray *windows = [[UIApplication sharedApplication] windows];
        for(UIWindow * tmpWin in windows)
        {
            if (tmpWin.windowLevel == UIWindowLevelNormal)
            {
                window = tmpWin;
                break;
            }
        }
    }
    UIView *frontView = [[window subviews] objectAtIndex:0];
    id nextResponder = [frontView nextResponder];

    if ([nextResponder isKindOfClass:[UIViewController class]])
        result = nextResponder;
    else
        result = window.rootViewController;
    return result;
}