我是ios的新手。我需要知道来自app delegate的当前视图控制器..我不知道这个，我不知道实现这个。我正在使用此代码来实现此功能，但它返回null值。 我按照这个链接 - Get current view controller from the app delegate (modal is possible) 需要帮助。
答案 0 :(得分：59)
这是我用来查找用户最有可能与之交互的当前视图控制器：
UIViewController + Utils.h
#import <UIKit/UIKit.h>
@interface UIViewController (Utils)
+(UIViewController*) currentViewController;
@end
<强>的UIViewController + Utils.m
#import "UIViewController+Utils.h"
@implementation UIViewController (Utils)
+(UIViewController*) findBestViewController:(UIViewController*)vc {
if (vc.presentedViewController) {
// Return presented view controller
return [UIViewController findBestViewController:vc.presentedViewController];
} else if ([vc isKindOfClass:[UISplitViewController class]]) {
// Return right hand side
UISplitViewController* svc = (UISplitViewController*) vc;
if (svc.viewControllers.count > 0)
return [UIViewController findBestViewController:svc.viewControllers.lastObject];
else
return vc;
} else if ([vc isKindOfClass:[UINavigationController class]]) {
// Return top view
UINavigationController* svc = (UINavigationController*) vc;
if (svc.viewControllers.count > 0)
return [UIViewController findBestViewController:svc.topViewController];
else
return vc;
} else if ([vc isKindOfClass:[UITabBarController class]]) {
// Return visible view
UITabBarController* svc = (UITabBarController*) vc;
if (svc.viewControllers.count > 0)
return [UIViewController findBestViewController:svc.selectedViewController];
else
return vc;
} else {
// Unknown view controller type, return last child view controller
return vc;
}
}
+(UIViewController*) currentViewController {
// Find best view controller
UIViewController* viewController = [UIApplication sharedApplication].keyWindow.rootViewController;
return [UIViewController findBestViewController:viewController];
}
@end
然后，当我需要应用程序中任何位置的当前视图控制器时，只需使用：
[UIViewController currentViewController]
答案 1 :(得分：13)
这是swift中的一些类/静态函数，我保存在Utility类中，可以帮助你：
// Returns the most recently presented UIViewController (visible)
class func getCurrentViewController() -> UIViewController? {
// If the root view is a navigation controller, we can just return the visible ViewController
if let navigationController = getNavigationController() {
return navigationController.visibleViewController
}
// Otherwise, we must get the root UIViewController and iterate through presented views
if let rootController = UIApplication.sharedApplication().keyWindow?.rootViewController {
var currentController: UIViewController! = rootController
// Each ViewController keeps track of the view it has presented, so we
// can move from the head to the tail, which will always be the current view
while( currentController.presentedViewController != nil ) {
currentController = currentController.presentedViewController
}
return currentController
}
return nil
}
// Returns the navigation controller if it exists
class func getNavigationController() -> UINavigationController? {
if let navigationController = UIApplication.sharedApplication().keyWindow?.rootViewController {
return navigationController as? UINavigationController
}
return nil
}
答案 2 :(得分：5)
这有助于我找到可见的视图控制器。我搜索了现有的方法，但没有找到任何方法。所以我写了自己的自定义。
-(id)getCurrentViewController
{
id WindowRootVC = [[[[UIApplication sharedApplication] delegate] window] rootViewController];
id currentViewController = [self findTopViewController:WindowRootVC];
return currentViewController;
}
-(id)findTopViewController:(id)inController
{
/* if ur using any Customs classes, do like this.
* Here SlideNavigationController is a subclass of UINavigationController.
* And ensure you check the custom classes before native controllers , if u have any in your hierarchy.
if ([inController isKindOfClass:[SlideNavigationController class]])
{
return [self findTopViewController:[inController visibleViewController]];
}
else */
if ([inController isKindOfClass:[UITabBarController class]])
{
return [self findTopViewController:[inController selectedViewController]];
}
else if ([inController isKindOfClass:[UINavigationController class]])
{
return [self findTopViewController:[inController visibleViewController]];
}
else if ([inController isKindOfClass:[UIViewController class]])
{
return inController;
}
else
{
NSLog(@"Unhandled ViewController class : %@",inController);
return nil;
}
}
样品使用：
-(void)someMethod
{
id currentVC = [self getCurrentViewController];
if (currentVC)
{
NSLog(@"currentVC :%@",currentVC);
}
}
答案 3 :(得分：4)
这取决于您设置UI的方式。如果以这种方式设置，您可以获取rootViewController并在层次结构中移动。
UIViewController *vc = self.window.rootViewController;
答案 4 :(得分：4)
UIViewController* actualVC = [anyViewController.navigationController.viewControllers lastObject];
答案 5 :(得分：3)
swift版本的jjv360很棒的答案， （我摆脱了一些冗余的回报，我认为Swift更具可读性）
func getCurrentViewController(_ vc: UIViewController) -> UIViewController? {
if let pvc = vc.presentedViewController {
return getCurrentViewController(pvc)
}
else if let svc = vc as? UISplitViewController, svc.viewControllers.count > 0 {
return getCurrentViewController(svc.viewControllers.last!)
}
else if let nc = vc as? UINavigationController, nc.viewControllers.count > 0 {
return getCurrentViewController(nc.topViewController!)
}
else if let tbc = vc as? UITabBarController {
if let svc = tbc.selectedViewController {
return getCurrentViewController(svc)
}
}
return vc
}
来自AppDelegate，
guard let rvc = self.window?.rootViewController else {
return
}
if let vc = getCurrentViewController(rvc) {
// do your stuff here
}
答案 6 :(得分：3)
我得到了根控制器，然后遍历所呈现的VC：
UIViewController *current = [UIApplication sharedApplication].keyWindow.rootViewController;
while (current.presentedViewController) {
current = current.presentedViewController;
}
//now you can use current, for example to present an alert view controller:
[current presentViewController:alert animated:YES completion:nil];
答案 7 :(得分：1)
| * |从导航视图控制器获取可见视图控制器
application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?)| * |从可见视图控制器呈现
let NavVccVar = UIApplication.sharedApplication().keyWindow?.rootViewController as! UINavigationController
let ShnSrnVar = NavVccVar.visibleViewController
答案 8 :(得分：1)
这是我尝试过的最佳解决方案
+ (UIViewController*) topMostController
{
UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;
while (topController.presentedViewController) {
topController = topController.presentedViewController;
}
return topController;
}
答案 9 :(得分：0)
我正在使用此代码 -
//in AppDelegate:
@interface AppDelegate()
{
id lastViewController;
}
@implementation AppDelegate
-(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:
(NSDictionary *)launchOptions
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleCurrentViewController) name:@"CurrentViewController" object:nil];
}
-(void)handleCurrentViewController:(NSNotification *)notification
{
if([[notification userInfo] objectForKey:@"lastViewController"])
{
lastViewController = [[notification userInfo] objectForKey:@"lastViewController"];
}
}
-(void)applicationDidEnterBackground:(UIApplication *)application
{
NSLog(@"last view controller is %@", [(UIViewController *)lastViewController class]);
}
@end
//在您要检测的每个ViewController中
@implementation SomeViewController
-(void) viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
[[NSNotificationCenter defaultCenter] postNotificationName:@"CurrentViewController" object:nil userInfo:[NSDictionary dictionaryWithObjectsAndKeys:self, @"lastViewController", nil]];
}
答案 10 :(得分：0)
我找到了这个，对我来说对于所有类型的segue和视图控制器都很有用。它很简单也很短，很不错。
+（UIViewController *）getTopController { UIViewController * topViewController = [UIApplication sharedApplication] .keyWindow.rootViewController;
while (topViewController.presentedViewController) { topViewController = topViewController.presentedViewController; } return topViewController; }
答案 11 :(得分：0)
Swift 解决方案 对于 iOS 13+ 我们有 SceneDelgate 和多个窗口，因此您需要使用以下代码：
private func getCurrentViewController() -> UIViewController? {
if let rootViewController = UIApplication.shared.windows.first?.rootViewController {
if let presentedViewController = rootViewController.presentedViewController {
return presentedViewController
}
return rootViewController
}
return nil
}