关于Presenting view controllers on

摘要: 关于形如 Presenting view controllers on detached view controllers is discouraged 的处理

使用模态跳转时，Xcode有时候会出现如下警告

Presenting view controllers on detached view controllersisdiscouraged <>

这样的警告代码，如果你认为你的层次之间没有问题（其实就是层次问题。present出来的模态窗口，禁止再使用present 来弹出其它的子窗口）只要把self直接模态跳转页面改成从根控制器跳转即可

解决方法：

把

ViewController *viewController = [[ViewController alloc] init];[selfpresentViewController:viewController animated:YEScompletion:nil];

改成

AppDelegate *delegate = (AppDelegate *)[UIApplicationsharedApplication].delegate;ViewController *viewController = [[ViewController alloc] init];[delegate.window.rootViewController presentViewController:viewController animated:YEScompletion:nil];

即可

方法一：就是通过上面的方法，先找到appdelegate然后获取window属性

KLViewController *rootVc = (KLViewController *)[(AppDelegate *)[UIApplication sharedApplication].delegatewindow].rootViewController;

这种方法除了找根控制器还能找appdelegate类里的定义的任何属性，如：

- (void) openOrcloseTheList {        AppDelegate *tempAppDelegate = (AppDelegate *)[[UIApplicationsharedApplication] delegate];if(tempAppDelegate.theListVC.closed) {        [tempAppDelegate.theListVC openListView];    }else{        [tempAppDelegate.theListVC closeListView];    }}

方法二：直接通过keyWindow来找根控制器，更直接

KLViewController *rootVc = (KLViewController *)[UIApplicationsharedApplication].keyWindow.rootViewController;

补充：

YZLoginViewController *yzLoginVc = [YZLoginViewController new];//找根控制器方法//1.找到appdelegate然后获取window属性AppDelegate *delegate = (AppDelegate *)[UIApplicationsharedApplication].delegate;[delegate.window.rootViewController presentViewController:yzLoginVc animated:YEScompletion:nil];//2.直接通过keyWindow来找根控制器YZYuQingViewController *rootVc = (YZYuQingViewController *)[UIApplicationsharedApplication].keyWindow.rootViewController;[rootVc presentViewController:yzLoginVc animated:YEScompletion:nil];

链接：https://www.jianshu.com/p/157cab691ad2