我遇到了一些情况,现在,它将是方便的,能够找到“最顶层”的视图控制器(一个负责当前视图),但还没有找到一种方法。
基本上,挑战是这样的:给定一个在一个类中执行,这个类不是一个视图控制器(或一个视图)[并且没有活动视图的地址],并且没有传递最顶层视图控制器的地址(或者,比如说,导航控制器的地址),是否有可能找到那个视图控制器?(如果是的话,是怎么做到的?)
或者,如果找不到,有没有可能找到最高处的风景?
我遇到了一些情况,现在,它将是方便的,能够找到“最顶层”的视图控制器(一个负责当前视图),但还没有找到一种方法。
基本上,挑战是这样的:给定一个在一个类中执行,这个类不是一个视图控制器(或一个视图)[并且没有活动视图的地址],并且没有传递最顶层视图控制器的地址(或者,比如说,导航控制器的地址),是否有可能找到那个视图控制器?(如果是的话,是怎么做到的?)
或者,如果找不到,有没有可能找到最高处的风景?
当前回答
之前的答案似乎不能处理rootController是UITabBarController或UINavigationController的情况。
下面是swift中适用于这些情况的函数:
func getCurrentView() -> UIViewController?
{
if let window = UIApplication.sharedApplication().keyWindow, var currentView: UIViewController = window.rootViewController
{
while (currentView.presentedViewController != nil)
{
if let presented = currentView.presentedViewController
{
currentView = presented
}
}
if currentView is UITabBarController
{
if let visible = (currentView as! UITabBarController).selectedViewController
{
currentView = visible;
}
}
if currentView is UINavigationController
{
if let visible = (currentView as! UINavigationController).visibleViewController
{
currentView = visible;
}
}
return currentView
}
return nil
}
其他回答
Swift 4.2中一个简洁而全面的解决方案,考虑了UINavigationControllers, UITabBarControllers, presenting和子视图控制器:
extension UIViewController {
func topmostViewController() -> UIViewController {
if let navigationVC = self as? UINavigationController,
let topVC = navigationVC.topViewController {
return topVC.topmostViewController()
}
if let tabBarVC = self as? UITabBarController,
let selectedVC = tabBarVC.selectedViewController {
return selectedVC.topmostViewController()
}
if let presentedVC = presentedViewController {
return presentedVC.topmostViewController()
}
if let childVC = children.last {
return childVC.topmostViewController()
}
return self
}
}
extension UIApplication {
func topmostViewController() -> UIViewController? {
return keyWindow?.rootViewController?.topmostViewController()
}
}
用法:
let viewController = UIApplication.shared.topmostViewController()
另一个解决方案依赖于responder链,它可能工作,也可能不工作,这取决于第一个responder是什么:
获取第一个响应器。 获取与第一个responder相关联的UIViewController。
示例伪代码:
+ (UIViewController *)currentViewController {
UIView *firstResponder = [self firstResponder]; // from the first link above, but not guaranteed to return a UIView, so this should be handled more appropriately.
UIViewController *viewController = [firstResponder viewController]; // from the second link above
return viewController;
}
这是对Eric的回答的改进:
UIViewController *_topMostController(UIViewController *cont) {
UIViewController *topController = cont;
while (topController.presentedViewController) {
topController = topController.presentedViewController;
}
if ([topController isKindOfClass:[UINavigationController class]]) {
UIViewController *visible = ((UINavigationController *)topController).visibleViewController;
if (visible) {
topController = visible;
}
}
return (topController != cont ? topController : nil);
}
UIViewController *topMostController() {
UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;
UIViewController *next = nil;
while ((next = _topMostController(topController)) != nil) {
topController = next;
}
return topController;
}
UIViewController *cont是一个辅助函数。
现在你所需要做的就是调用topMostController()和最顶端的UIViewController应该被返回!
我的问题有点不同,我在我的应用程序中使用SWRevealViewController。 我使用了Yuchen Zhong的答案,但它总是返回topViewController作为SWRevealViewController。对于那些使用SWRevealViewController或其他一些pod来开发侧菜单的人。以下是我对钟宇晨回答的延伸:
extension UIApplication {
class func topViewController() -> UIViewController? {
var topVC = shared.keyWindow!.rootViewController
while true {
if let presented = topVC?.presentedViewController {
topVC = presented
} else if let nav = topVC as? UINavigationController {
topVC = nav.visibleViewController
} else if let tab = topVC as? UITabBarController {
topVC = tab.selectedViewController
}else if let swRVC = topVC as? SWRevealViewController {
topVC = swRVC.frontViewController
} else {
break
}
}
return topVC
}
}
为了完成Eric的回答(谁省略了弹出窗口,导航控制器,选项卡控制器,视图控制器添加为子视图到一些其他的视图控制器遍历),这是我的版本返回当前可见的视图控制器:
=====================================================================
- (UIViewController*)topViewController {
return [self topViewControllerWithRootViewController:[UIApplication sharedApplication].keyWindow.rootViewController];
}
- (UIViewController*)topViewControllerWithRootViewController:(UIViewController*)viewController {
if ([viewController isKindOfClass:[UITabBarController class]]) {
UITabBarController* tabBarController = (UITabBarController*)viewController;
return [self topViewControllerWithRootViewController:tabBarController.selectedViewController];
} else if ([viewController isKindOfClass:[UINavigationController class]]) {
UINavigationController* navContObj = (UINavigationController*)viewController;
return [self topViewControllerWithRootViewController:navContObj.visibleViewController];
} else if (viewController.presentedViewController && !viewController.presentedViewController.isBeingDismissed) {
UIViewController* presentedViewController = viewController.presentedViewController;
return [self topViewControllerWithRootViewController:presentedViewController];
}
else {
for (UIView *view in [viewController.view subviews])
{
id subViewController = [view nextResponder];
if ( subViewController && [subViewController isKindOfClass:[UIViewController class]])
{
if ([(UIViewController *)subViewController presentedViewController] && ![subViewController presentedViewController].isBeingDismissed) {
return [self topViewControllerWithRootViewController:[(UIViewController *)subViewController presentedViewController]];
}
}
}
return viewController;
}
}
=====================================================================
现在你需要做的就是像下面这样调用上面的方法:
UIViewController *topMostViewControllerObj = [self topViewController];