我可以假设，查看屏幕上显示的控制器自动从主故事板或通过设置应用程序的 window.rootViewController 属性进行实例化。

As I can assume, view controller being presented on the screen was instantiated either automatically from main storyboard or by setting app's window.rootViewController property.

在任何一种情况下，您都可以再次设置 rootViewController 作为 vc 。要更改应用程序的rootViewController，您需要替换以下代码行：

In either case you can set rootViewController again to be your vc. To change rootViewController of your app you need to replace this line of code:

self.presentViewController(vc, animated: true, completion: nil)

...其中一个选项如下。

... with one of the options bellow.

Objective-C

UIWindow *window = (UIWindow *)[[UIApplication sharedApplication].windows firstObject];
window.rootViewController = vc;

Swift

let window = UIApplication.sharedApplication().windows[0] as UIWindow;
window.rootViewController = vc;

使用过渡动画导航：

Objective-C

UIWindow *window = (UIWindow *)[[UIApplication sharedApplication].windows firstObject];
[UIView transitionFromView:window.rootViewController.view
                    toView:vc.view
                  duration:0.65f
                   options:UIViewAnimationOptionTransitionCrossDissolve // transition animation
                completion:^(BOOL finished){
                    window.rootViewController = vc;
                }];

Swift

let window = UIApplication.sharedApplication().windows[0] as UIWindow;
UIView.transitionFromView(
    window.rootViewController.view,
    toView: vc.view,
    duration: 0.65,
    options: .TransitionCrossDissolve,
    completion: {
        finished in window.rootViewController = vc
    })

备注：
一旦rootViewController值被更改，原始视图控制器引用计数应该变为0，因此它将从内存中删除！

Remarks: Once rootViewController value gets changed your original view controller reference count should became 0 hence it will be removed from the memory!