如何在iOS上找到最顶层的视图控制器
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我现在遇到了几个案例，它们可以方便地找到“最顶层”的视图控制器（负责当前视图的控制器），但还没有找到办法。
基本上挑战是这样的：假设一个人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]并且还没有传递最顶层视图控制器的地址（或者说，导航控制器的地址），是否可以找到该视图控制器？ （如果是这样，怎么样？）
或者，如果失败了，是否有可能找到最顶层的视图？
答案
ios 4在UIWindow上引入了rootViewController属性：
[UIApplication sharedApplication].keyWindow.rootViewController;
您需要在创建视图控制器后自己设置它。
另一答案
- (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;
}
}
另一答案
在Swift中简单扩展UIApplication：
注意：
它关心moreNavigationController内的UITabBarController
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
}
}
用法简单：
if let topViewController = UIApplication.topViewController() {
//do sth with top view controller
}
另一答案
@implementation UIWindow (Extensions)
- (UIViewController*) topMostController
{
UIViewController *topController = [self rootViewController];
while (topController.presentedViewController) {
topController = topController.presentedViewController;
}
return topController;
}
@end
另一答案
这是我对此的看法。感谢@Stakenborg指出了跳过让UIAlertView成为最顶级控制器的方法
-(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;
}
另一答案
对于最新的Swift版本：
创建一个文件，将其命名为UIWindowExtension.swift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
}
在任何地方使用它：
if let topVC = getTopViewController() {
}
另一答案
这对我有用。
我发现有时控制器在关键窗口上是零，因为keyWindow是一些操作系统，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;
}
另一答案
扩展@ Eric的答案，你需要注意keyWindow实际上是你想要的窗口。例如，如果您在警报视图中点击某些内容后尝试使用此方法，则keyWindow实际上将成为警报的窗口，这无疑会给您带来问题。当通过警报处理深度链接并导致SIGABRT没有堆栈跟踪时，这发生在我的野外。要调试的总婊子。
这是我现在使用的代码：
- (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) {
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