iOS 获取当前正在显示的ViewController

#import "UIWindow+SHHelper.h"

@implementation UIWindow (SHHelper)

- (UIViewController*)sh_topMostController
{
//  getting rootViewController
UIViewController *topController = [self rootViewController];

//  Getting topMost ViewController
while ([topController presentedViewController]) topController = [topController presentedViewController];

//  Returning topMost ViewController
return topController;
}

- (UIViewController*)sh_currentViewController;
{
UIViewController *currentViewController = [self sh_topMostController];

while ([currentViewController isKindOfClass:[UINavigationController class]] && [(UINavigationController*)currentViewController topViewController])
currentViewController = [(UINavigationController*)currentViewController topViewController];

return currentViewController;
}

@end

//满足一个日常的需求:在UITableviewcell里面的UIView模块里面，调用self.navigationcontroller pushviewcontroller推入一个新的viewcontroller，需要获取其上层的UIViewcontroller, 可以使用下面的方法:
- (UIViewController *)sh_viewController
{
UIResponder *responder = self;
while ((responder = [responder nextResponder])){
if ([responder isKindOfClass: [UIViewController class]]){
return (UIViewController *)responder;
}
}
return nil;
}

#import "UIViewController+SHHelper.h"

@implementation UIViewController (SHHelper)

- (UIViewController*)sh_topMostController
{
UIViewController *topController = self ;

while ([self presentedViewController])
topController = [topController presentedViewController];

return topController;
}

- (UIViewController*)sh_currentViewController;
{
UIViewController *currentViewController = [self sh_topMostController];

while ([currentViewController isKindOfClass:[UINavigationController class]] && [(UINavigationController*)currentViewController topViewController])
currentViewController = [(UINavigationController*)currentViewController topViewController];

return currentViewController;
}

//我们在非视图类中想要随时展示一个view时，需要将被展示的view加到当前view的子视图，或用当前view presentViewController，或pushViewContrller，这些操作都需要获取当前正在显示的ViewController。
//获取当前view的UIViewController
+ (UIViewController *)sh_currentViewControllerFromcurrentView{

UIViewController *result = nil;

// 1. get current window
UIWindow * window = [[UIApplication sharedApplication] keyWindow];
if (window.windowLevel != UIWindowLevelNormal) {
NSArray *windows = [[UIApplication sharedApplication] windows];
for(UIWindow * tempWindow in windows) {
if (tempWindow.windowLevel == UIWindowLevelNormal) {
window = tempWindow;
break;
}
}
}

// 2. get current View Controller
UIView *frontView = [[window subviews] objectAtIndex:0];
id nextResponder = [frontView nextResponder];
if ([nextResponder isKindOfClass:[UIViewController class]]) {
result = nextResponder;
} else {
result = window.rootViewController;
}
return result;
}

//获取当前屏幕中present出来的viewcontroller。
- (UIViewController *)getPresentedViewController
{
UIViewController *appRootVC = [UIApplication sharedApplication].keyWindow.rootViewController;
UIViewController *topVC = appRootVC;
if (topVC.presentedViewController) {
topVC = topVC.presentedViewController;
}

return topVC;
}

@end