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
使用扩展为Swift获得最顶部的视图控制器
代码:
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()
其他回答
iOS 4在UIWindow上引入了rootViewController属性:
[UIApplication sharedApplication].keyWindow.rootViewController;
你需要在创建视图控制器后自己设置。
很多答案都是不完整的。虽然这是在Objective-C中,但这是我现在能把它们放在一起的最好的编译,作为一个非递归的块:
链接到Gist,以防修改:https://gist.github.com/benguild/0d149bb3caaabea2dac3d2dca58c0816 供参考/比较的代码:
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;
};
这个答案包含了childViewControllers,并维护了一个干净易读的实现。
+ (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;
}
以下是我的看法。感谢@Stakenborg指出了跳过UIAlertView作为最顶层控制器的方法
-(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;
}
我认为你需要一个公认的答案和@fishstix的组合
+ (UIViewController*) topMostController
{
UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;
while (topController.presentedViewController) {
topController = topController.presentedViewController;
}
return topController;
}
Swift 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
}