如何解决如何在iOS上找到最上层的视图控制器
|| 我现在遇到过两种情况,可以很方便地找到“最高”视图控制器(负责当前视图的视图控制器),但还没有找到一种方法。 基本上,挑战是这样的:假设一个人正在一个不是视图控制器(或视图)的类中执行[并且没有活动视图的地址],并且没有传递最高视图控制器的地址(或者说导航控制器的地址),是否可以找到该视图控制器? (如果是的话,如何?) 否则,是否有可能找到最顶层的视图?解决方法
iOS 4在UIWindow上引入了rootViewController属性:
[UIApplication sharedApplication].keyWindow.rootViewController;
不过,在创建视图控制器后,您需要自己进行设置。
,我认为您需要接受的答案和@fishstix的组合
+ (UIViewController*) topMostController
{
UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;
while (topController.presentedViewController) {
topController = topController.presentedViewController;
}
return topController;
}
迅捷3.0+
func topMostController() -> UIViewController? {
guard let window = UIApplication.shared.keyWindow,let rootViewController = window.rootViewController else {
return nil
}
var topController = rootViewController
while let newTopController = topController.presentedViewController {
topController = newTopController
}
return topController
}
,为了完成JonasG的答案(在遍历时忽略了标签栏控制器),这是我返回当前可见的视图控制器的版本:
- (UIViewController*)topViewController {
return [self topViewControllerWithRootViewController:[UIApplication sharedApplication].keyWindow.rootViewController];
}
- (UIViewController*)topViewControllerWithRootViewController:(UIViewController*)rootViewController {
if ([rootViewController isKindOfClass:[UITabBarController class]]) {
UITabBarController* tabBarController = (UITabBarController*)rootViewController;
return [self topViewControllerWithRootViewController:tabBarController.selectedViewController];
} else if ([rootViewController isKindOfClass:[UINavigationController class]]) {
UINavigationController* navigationController = (UINavigationController*)rootViewController;
return [self topViewControllerWithRootViewController:navigationController.visibleViewController];
} else if (rootViewController.presentedViewController) {
UIViewController* presentedViewController = rootViewController.presentedViewController;
return [self topViewControllerWithRootViewController:presentedViewController];
} else {
return rootViewController;
}
}
,完整的非递归版本,照顾不同的情况:
视图控制器正在呈现另一个视图
视图控制器是UINavigationController
视图控制器是UITabBarController
目标C
UIViewController *topViewController = self.window.rootViewController;
while (true)
{
if (topViewController.presentedViewController) {
topViewController = topViewController.presentedViewController;
} else if ([topViewController isKindOfClass:[UINavigationController class]]) {
UINavigationController *nav = (UINavigationController *)topViewController;
topViewController = nav.topViewController;
} else if ([topViewController isKindOfClass:[UITabBarController class]]) {
UITabBarController *tab = (UITabBarController *)topViewController;
topViewController = tab.selectedViewController;
} else {
break;
}
}
迅捷4+
extension UIWindow {
func topViewController() -> UIViewController? {
var top = self.rootViewController
while true {
if let presented = top?.presentedViewController {
top = presented
} else if let nav = top as? UINavigationController {
top = nav.visibleViewController
} else if let tab = top as? UITabBarController {
top = tab.selectedViewController
} else {
break
}
}
return top
}
}
,使用扩展获取Swift的顶级视图控制器
码:
extension UIViewController {
@objc func topMostViewController() -> UIViewController {
// Handling Modal views
if let presentedViewController = self.presentedViewController {
return presentedViewController.topMostViewController()
}
// Handling UIViewController\'s added as subviews to some other views.
else {
for view in self.view.subviews
{
// Key property which most of us are unaware of / rarely use.
if let subViewController = view.next {
if subViewController is UIViewController {
let viewController = subViewController as! UIViewController
return viewController.topMostViewController()
}
}
}
return self
}
}
}
extension UITabBarController {
override func topMostViewController() -> UIViewController {
return self.selectedViewController!.topMostViewController()
}
}
extension UINavigationController {
override func topMostViewController() -> UIViewController {
return self.visibleViewController!.topMostViewController()
}
}
用法:
UIApplication.sharedApplication().keyWindow!.rootViewController!.topMostViewController()
,为了完成Eric的答案(遍历时遗漏了弹出窗口,导航控制器,tabbarcontroller,作为子视图添加到其他视图控制器的视图控制器),这是我返回当前可见的视图控制器的版本:
================================================== ===================
- (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,要获得最高的视图控制器,您需要做的就是调用上述方法,如下所示:
UIViewController *topMostViewControllerObj = [self topViewController];
,该答案包括“ 12”字样,并保持清晰易懂的实现方式。
+ (UIViewController *)topViewController
{
UIViewController *rootViewController = [UIApplication sharedApplication].keyWindow.rootViewController;
return [rootViewController topVisibleViewController];
}
- (UIViewController *)topVisibleViewController
{
if ([self isKindOfClass:[UITabBarController class]])
{
UITabBarController *tabBarController = (UITabBarController *)self;
return [tabBarController.selectedViewController topVisibleViewController];
}
else if ([self isKindOfClass:[UINavigationController class]])
{
UINavigationController *navigationController = (UINavigationController *)self;
return [navigationController.visibleViewController topVisibleViewController];
}
else if (self.presentedViewController)
{
return [self.presentedViewController topVisibleViewController];
}
else if (self.childViewControllers.count > 0)
{
return [self.childViewControllers.lastObject topVisibleViewController];
}
return self;
}
,我最近在我的一个项目中遇到了这种情况,当网络状态更改时,该项目要求显示一个通知视图,无论显示的控制器是什么,类型是什么(UINavigationController,经典控制器或自定义视图控制器)。
因此,我刚刚发布了我的代码,该代码非常简单,并且实际上是基于协议的,因此对于每种类型的容器控制器都非常灵活。
它似乎与最后的答案有关,但是方式非常灵活。
您可以在此处获取代码:PPTopMostController
并获得使用最多的控制器
UIViewController *c = [UIViewController topMostController];
,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;
}
_topMostController(UIViewController *cont)
是辅助功能。
现在您需要做的就是调用topMostController()
,并且应该返回最上面的UIViewController!
,- (UIViewController*)topViewController {
return [self topViewControllerWithRootViewController:[UIApplication sharedApplication].keyWindow.rootViewController];
}
- (UIViewController*)topViewControllerWithRootViewController:(UIViewController*)rootViewController {
if ([rootViewController isKindOfClass:[UITabBarController class]]) {
UITabBarController* tabBarController = (UITabBarController*)rootViewController;
return [self topViewControllerWithRootViewController:tabBarController.selectedViewController];
} else if ([rootViewController isKindOfClass:[UINavigationController class]]) {
UINavigationController* navigationController = (UINavigationController*)rootViewController;
return [self topViewControllerWithRootViewController:navigationController.visibleViewController];
} else if (rootViewController.presentedViewController) {
UIViewController* presentedViewController = rootViewController.presentedViewController;
return [self topViewControllerWithRootViewController:presentedViewController];
} else {
return rootViewController;
}
}
,在Swift中对UIApplication
的简单扩展:
注意:
在乎UITabBarController
内的moreNavigationController
extension UIApplication {
class func topViewController(baseViewController: UIViewController? = UIApplication.sharedApplication().keyWindow?.rootViewController) -> UIViewController? {
if let navigationController = baseViewController as? UINavigationController {
return topViewController(navigationController.visibleViewController)
}
if let tabBarViewController = baseViewController as? UITabBarController {
let moreNavigationController = tabBarViewController.moreNavigationController
if let topViewController = moreNavigationController.topViewController where topViewController.view.window != nil {
return topViewController(topViewController)
} else if let selectedViewController = tabBarViewController.selectedViewController {
return topViewController(selectedViewController)
}
}
if let splitViewController = baseViewController as? UISplitViewController where splitViewController.viewControllers.count == 1 {
return topViewController(splitViewController.viewControllers[0])
}
if let presentedViewController = baseViewController?.presentedViewController {
return topViewController(presentedViewController)
}
return baseViewController
}
}
简单用法:
if let topViewController = UIApplication.topViewController() {
//do sth with top view controller
}
,@implementation UIWindow(扩展名)
-(UIViewController *)topMostController
{
UIViewController * topController = [self rootViewController];
while(topController.presentedViewController){
topController = topController.presentedViewController;
}
返回topController;
}
@结束
,这是我的看法。感谢@Stakenborg指出了跳过让UIAlertView成为最高控制器的方法
-(UIWindow *) returnWindowWithWindowLevelNormal
{
NSArray *windows = [UIApplication sharedApplication].windows;
for(UIWindow *topWindow in windows)
{
if (topWindow.windowLevel == UIWindowLevelNormal)
return topWindow;
}
return [UIApplication sharedApplication].keyWindow;
}
-(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;
}
,对于最新的Swift版本:
创建一个文件,将其命名为“ 25”,并粘贴以下代码段:
import UIKit
public extension UIWindow {
public var visibleViewController: UIViewController? {
return UIWindow.getVisibleViewControllerFrom(self.rootViewController)
}
public static func getVisibleViewControllerFrom(vc: UIViewController?) -> UIViewController? {
if let nc = vc as? UINavigationController {
return UIWindow.getVisibleViewControllerFrom(nc.visibleViewController)
} else if let tc = vc as? UITabBarController {
return UIWindow.getVisibleViewControllerFrom(tc.selectedViewController)
} else {
if let pvc = vc?.presentedViewController {
return UIWindow.getVisibleViewControllerFrom(pvc)
} else {
return vc
}
}
}
}
func getTopViewController() -> UIViewController? {
let appDelegate = UIApplication.sharedApplication().delegate
if let window = appDelegate!.window {
return window?.visibleViewController
}
return nil
}
可以在任何地方使用它:
if let topVC = getTopViewController() {
}
,使用以下扩展名抓取当前可见的UIViewController
。适用于Swift 4.0及更高版本
Swift 4.0及更高版本:
extension UIApplication {
class func topViewController(_ viewController: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {
if let nav = viewController as? UINavigationController {
return topViewController(nav.visibleViewController)
}
if let tab = viewController as? UITabBarController {
if let selected = tab.selectedViewController {
return topViewController(selected)
}
}
if let presented = viewController?.presentedViewController {
return topViewController(presented)
}
return viewController
}
}
如何使用?
let objViewcontroller = UIApplication.topViewController()
,这对我有用。
我发现有时控制器在按键窗口上为零,因为keyWindow是一些操作系统的东西,例如警报等。
+ (UIViewController*)topMostController
{
UIWindow *topWndow = [UIApplication sharedApplication].keyWindow;
UIViewController *topController = topWndow.rootViewController;
if (topController == nil)
{
// The windows in the array are ordered from back to front by window level; thus,// the last window in the array is on top of all other app windows.
for (UIWindow *aWndow in [[UIApplication sharedApplication].windows reverseObjectEnumerator])
{
topController = aWndow.rootViewController;
if (topController)
break;
}
}
while (topController.presentedViewController) {
topController = topController.presentedViewController;
}
return topController;
}
,在扩展@Eric \的答案时,需要注意keyWindow实际上是您想要的窗口。例如,如果您在敲击警报视图中的某些内容后尝试使用此方法,则keyWindow实际上将是警报的窗口,这无疑会给您造成问题。这是我在通过警报处理深层链接时在野外发生的事情,并导致SIGABRT出现NO STACK TRACE。总母狗要调试。
这是我现在正在使用的代码:
- (UIViewController *)getTopMostViewController {
UIWindow *topWindow = [UIApplication sharedApplication].keyWindow;
if (topWindow.windowLevel != UIWindowLevelNormal) {
NSArray *windows = [UIApplication sharedApplication].windows;
for(topWindow in windows)
{
if (topWindow.windowLevel == UIWindowLevelNormal)
break;
}
}
UIViewController *topViewController = topWindow.rootViewController;
while (topViewController.presentedViewController) {
topViewController = topViewController.presentedViewController;
}
return topViewController;
}
随意将其与从该问题的其他答案中检索您喜欢的顶视图控制器的任何方式混合使用。
,另一种Swift解决方案:
static func topMostController() -> UIViewController {
var topController = UIApplication.sharedApplication().keyWindow?.rootViewController
while (topController?.presentedViewController != nil) {
topController = topController?.presentedViewController
}
return topController!
}
,另一个Swift解决方案
func topController() -> UIViewController? {
// recursive follow
func follow(from:UIViewController?) -> UIViewController? {
if let to = (from as? UITabBarController)?.selectedViewController {
return follow(to)
} else if let to = (from as? UINavigationController)?.visibleViewController {
return follow(to)
} else if let to = from?.presentedViewController {
return follow(to)
}
return from
}
let root = UIApplication.sharedApplication().keyWindow?.rootViewController
return follow(root)
}
,这个解决方案是最完整的。它考虑到:
UINavigationController
UIPageViewController
UITabBarController
以及来自顶部视图控制器的最顶部显示的视图控制器
该示例在Swift 3中。
有3个重载
//Get the topmost view controller for the current application.
public func MGGetTopMostViewController() -> UIViewController? {
if let currentWindow:UIWindow = UIApplication.shared.keyWindow {
return MGGetTopMostViewController(fromWindow: currentWindow)
}
return nil
}
//Gets the topmost view controller from a specific window.
public func MGGetTopMostViewController(fromWindow window:UIWindow) -> UIViewController? {
if let rootViewController:UIViewController = window.rootViewController
{
return MGGetTopMostViewController(fromViewController: rootViewController)
}
return nil
}
//Gets the topmost view controller starting from a specific UIViewController
//Pass the rootViewController into this to get the apps top most view controller
public func MGGetTopMostViewController(fromViewController viewController:UIViewController) -> UIViewController {
//UINavigationController
if let navigationViewController:UINavigationController = viewController as? UINavigationController {
let viewControllers:[UIViewController] = navigationViewController.viewControllers
if navigationViewController.viewControllers.count >= 1 {
return MGGetTopMostViewController(fromViewController: viewControllers[viewControllers.count - 1])
}
}
//UIPageViewController
if let pageViewController:UIPageViewController = viewController as? UIPageViewController {
if let viewControllers:[UIViewController] = pageViewController.viewControllers {
if viewControllers.count >= 1 {
return MGGetTopMostViewController(fromViewController: viewControllers[0])
}
}
}
//UITabViewController
if let tabBarController:UITabBarController = viewController as? UITabBarController {
if let selectedViewController:UIViewController = tabBarController.selectedViewController {
return MGGetTopMostViewController(fromViewController: selectedViewController)
}
}
//Lastly,Attempt to get the topmost presented view controller
var presentedViewController:UIViewController! = viewController.presentedViewController
var nextPresentedViewController:UIViewController! = presentedViewController?.presentedViewController
//If there is a presented view controller,get the top most prensentedViewController and return it.
if presentedViewController != nil {
while nextPresentedViewController != nil {
//Set the presented view controller as the next one.
presentedViewController = nextPresentedViewController
//Attempt to get the next presented view controller
nextPresentedViewController = presentedViewController.presentedViewController
}
return presentedViewController
}
//If there is no topmost presented view controller,return the view controller itself.
return viewController
}
,Swift 4.2扩展
extension UIApplication {
class func topViewController(controller: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {
if let navigationController = controller as? UINavigationController {
return topViewController(controller: navigationController.visibleViewController)
}
if let tabController = controller as? UITabBarController {
if let selected = tabController.selectedViewController {
return topViewController(controller: selected)
}
}
if let presented = controller?.presentedViewController {
return topViewController(controller: presented)
}
return controller
}
}
可以在任何地方使用它,
UIApplication.topViewController()?.present(yourController,animated: true,completion: nil)
或喜欢
UIApplication.topViewController()?
.navigationController?
.popToViewController(yourController,animated: true)
适合任何类,如UINavigationController,UITabBarController
请享用!
,Swift中的绝佳解决方案,可在AppDelegate中实现
func getTopViewController()->UIViewController{
return topViewControllerWithRootViewController(UIApplication.sharedApplication().keyWindow!.rootViewController!)
}
func topViewControllerWithRootViewController(rootViewController:UIViewController)->UIViewController{
if rootViewController is UITabBarController{
let tabBarController = rootViewController as! UITabBarController
return topViewControllerWithRootViewController(tabBarController.selectedViewController!)
}
if rootViewController is UINavigationController{
let navBarController = rootViewController as! UINavigationController
return topViewControllerWithRootViewController(navBarController.visibleViewController)
}
if let presentedViewController = rootViewController.presentedViewController {
return topViewControllerWithRootViewController(presentedViewController)
}
return rootViewController
}
,我认为大多数答案都完全忽略了“ 40”,因此我通过以下实现处理了该用例。
+ (UIViewController *)topMostController {
UIViewController * topController = [UIApplication sharedApplication].keyWindow.rootViewController;
while (topController.presentedViewController || [topController isMemberOfClass:[UINavigationController class]]) {
if([topController isMemberOfClass:[UINavigationController class]]) {
topController = [topController childViewControllers].lastObject;
} else {
topController = topController.presentedViewController;
}
}
return topController;
}
,Swift 4.2中一个简洁而全面的解决方案,考虑了UINavigationControllers,UITabBarControllers,表示的和子视图控制器:
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()
,不确定这是否可以通过找到最顶部的视图控制器来帮助您完成什么,但是我试图提供一个新的视图控制器,但是如果我的根视图控制器已经有一个模态对话框,它将被阻止,因此我将使用以下代码循环到所有模态视图控制器的顶部:
UIViewController* parentController =[UIApplication sharedApplication].keyWindow.rootViewController;
while( parentController.presentedViewController &&
parentController != parentController.presentedViewController )
{
parentController = parentController.presentedViewController;
}
,迅速:
extension UIWindow {
func visibleViewController() -> UIViewController? {
if let rootViewController: UIViewController = self.rootViewController {
return UIWindow.getVisibleViewControllerFrom(rootViewController)
}
return nil
}
class func getVisibleViewControllerFrom(vc:UIViewController) -> UIViewController {
if vc.isKindOfClass(UINavigationController.self) {
let navigationController = vc as UINavigationController
return UIWindow.getVisibleViewControllerFrom( navigationController.visibleViewController)
} else if vc.isKindOfClass(UITabBarController.self) {
let tabBarController = vc as UITabBarController
return UIWindow.getVisibleViewControllerFrom(tabBarController.selectedViewController!)
} else {
if let presentedViewController = vc.presentedViewController {
return UIWindow.getVisibleViewControllerFrom(presentedViewController.presentedViewController!)
} else {
return vc;
}
}
}
用法:
if let topController = window.visibleViewController() {
println(topController)
}
,下面的两个函数可以帮助在视图控制器堆栈上找到topViewController。您稍后可能需要自定义,但是对于此代码而言,了解topViewController或viewControllers堆栈的概念很棒。
- (UIViewController*)findTopViewController {
id topControler = [self topMostController];
UIViewController* topViewController;
if([topControler isKindOfClass:[UINavigationController class]]) {
topViewController = [[(UINavigationController*)topControler viewControllers] lastObject];
} else if ([topControler isKindOfClass:[UITabBarController class]]) {
//Here you can get reference of top viewcontroller from stack of viewcontrollers on UITabBarController
} else {
//topController is a preented viewController
topViewController = (UIViewController*)topControler;
}
//NSLog(@\"Top ViewController is: %@\",NSStringFromClass([topController class]));
return topViewController;
}
- (UIViewController*)topMostController
{
UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;
while (topController.presentedViewController) {
topController = topController.presentedViewController;
}
//NSLog(@\"Top View is: %@\",NSStringFromClass([topController class]));
return topController;
}
您可以使用[viewController Class]方法找出viewController的类类型。
,还有另一个Swift解决方案
extension UIViewController {
static var topmostViewController: UIViewController? {
return UIApplication.sharedApplication().keyWindow?.topmostViewController
}
var topmostViewController: UIViewController? {
return presentedViewController?.topmostViewController ?? self
}
}
extension UINavigationController {
override var topmostViewController: UIViewController? {
return visibleViewController?.topmostViewController
}
}
extension UITabBarController {
override var topmostViewController: UIViewController? {
return selectedViewController?.topmostViewController
}
}
extension UIWindow {
var topmostViewController: UIViewController? {
return rootViewController?.topmostViewController
}
}
,这些答案很多都不完整。尽管这是在Objective-C中进行的,但作为非递归块,这是我现在可以将它们放在一起的最好的汇编:
链接到Gist,以防万一它被修订:https://gist.github.com/benguild/0d149bb3caaabea2dac3d2dca58c0816
参考/比较代码:
UIViewController *(^topmostViewControllerForFrontmostNormalLevelWindow)(void) = ^UIViewController *{
// NOTE: Adapted from various stray answers here:
// https://stackoverflow.com/questions/6131205/iphone-how-to-find-topmost-view-controller/20515681
UIViewController *viewController;
for (UIWindow *window in UIApplication.sharedApplication.windows.reverseObjectEnumerator.allObjects) {
if (window.windowLevel == UIWindowLevelNormal) {
viewController = window.rootViewController;
break;
}
}
while (viewController != nil) {
if ([viewController isKindOfClass:[UITabBarController class]]) {
viewController = ((UITabBarController *)viewController).selectedViewController;
} else if ([viewController isKindOfClass:[UINavigationController class]]) {
viewController = ((UINavigationController *)viewController).visibleViewController;
} else if (viewController.presentedViewController != nil && !viewController.presentedViewController.isBeingDismissed) {
viewController = viewController.presentedViewController;
} else if (viewController.childViewControllers.count > 0) {
viewController = viewController.childViewControllers.lastObject;
} else {
BOOL repeat = NO;
for (UIView *view in viewController.view.subviews.reverseObjectEnumerator.allObjects) {
if ([view.nextResponder isKindOfClass:[UIViewController class]]) {
viewController = (UIViewController *)view.nextResponder;
repeat = YES;
break;
}
}
if (!repeat) {
break;
}
}
}
return viewController;
};
,如果根控制器是导航控制器,则找到顶部可见控制器的正确方法是:
UIViewController *rootVC = [[UIApplication sharedApplication] keyWindow].rootViewController;
if ([rootVC respondsToSelector:@selector(visibleViewController)])
{
UIViewController *topVC = [(UINavigationController *)rootVC visibleViewController];
// do your thing with topVC
}
这是UINavigationController.h的摘录:
@property(nonatomic,readonly,retain) UIViewController *topViewController; // The top view controller on the stack.
@property(nonatomic,retain) UIViewController *visibleViewController; // Return modal view controller if it exists. Otherwise the top view controller.
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