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
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!
其他回答
我认为Rajesh的解决方案几乎是完美的,但我认为从上到下遍历子视图更好,我改为如下:
+ (UIViewController *)topViewController:(UIViewController *)viewController{
if (viewController.presentedViewController)
{
UIViewController *presentedViewController = viewController.presentedViewController;
return [self topViewController:presentedViewController];
}
else if ([viewController isKindOfClass:[UITabBarController class]])
{
UITabBarController *tabBarController = (UITabBarController *)viewController;
return [self topViewController:tabBarController.selectedViewController];
}
else if ([viewController isKindOfClass:[UINavigationController class]])
{
UINavigationController *navController = (UINavigationController *)viewController;
return [self topViewController:navController.visibleViewController];
}
// Handling UIViewController's added as subviews to some other views.
else {
NSInteger subCount = [viewController.view subviews].count - 1;
for (NSInteger index = subCount; index >=0 ; --index)
{
UIView *view = [[viewController.view subviews] objectAtIndex:index];
id subViewController = [view nextResponder]; // Key property which most of us are unaware of / rarely use.
if ( subViewController && [subViewController isKindOfClass:[UIViewController class]])
{
return [self topViewController:subViewController];
}
}
return viewController;
}
}
- (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;
}
}
这对于从任何根视图控件中找到top viewcontroller1非常有效
+ (UIViewController *)topViewControllerFor:(UIViewController *)viewController
{
if(!viewController.presentedViewController)
return viewController;
return [MF5AppDelegate topViewControllerFor:viewController.presentedViewController];
}
/* View Controller for Visible View */
AppDelegate *app = [UIApplication sharedApplication].delegate;
UIViewController *visibleViewController = [AppDelegate topViewControllerFor:app.window.rootViewController];
你应该使用:
[UIApplication sharedApplication].window.rootViewController;
当[UIApplication sharedApplication]上有一个uiactionsheet时。keyWindow,这是不正确的使用keyWindow在这个答案中提到。
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。