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
最新Swift版本: 创建一个文件,命名为UIWindowExtension.swift,并粘贴以下代码片段:
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.shared.delegate
if let window = appDelegate!.window {
return window?.visibleViewController
}
return nil
}
可以在任何地方使用:
if let topVC = getTopViewController() {
}
其他回答
以下是对我有效的方法。
我发现有时候控制器在键窗口上是nil,因为键窗口是一些操作系统的东西,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;
}
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];
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];