获取TopMostViewController

2016-01-08

判断当前窗口是否被加载了

if (self.isViewLoaded && self.view.window ) {
//Do Something
}

获取当前显示的ViewController

因为所有的ViewController都在Window里,而App都是在KeyWindow上,所以可以用以下代码获得

- (UIViewController *)getCurrentVC {
    //1. 先找到KeyWindow
    UIWindow * window = [[UIApplication sharedApplication] keyWindow];
    //2. 正常情况下KeyWindow应该是在UIWindowLevelNormal,有Alert的时候KeyWindow就是Alert框
    if (window.windowLevel != UIWindowLevelNormal)
    {
        //3. 如果不是UIWindowLevelNormal,那么找到UIWindowLevelNormal级别的Window
        // 这里有个缺陷,因为UIWindowLevelNormal的不一定只有一个,虽然正常情况下只有一个
        NSArray *windows = [[UIApplication sharedApplication] windows];
        for(UIWindow * tmpWin in windows)
        {
            if (tmpWin.windowLevel == UIWindowLevelNormal)
            {
                //找到了UIWindowLevelNormal的Window
                window = tmpWin;
                break;
            }
        }
    }
    //4. 判断RootViewController不是TabBarVC和NaviVC,且是ViewController
    id result = window.rootViewController;
    BOOL isViewController = ![result isKindOfClass:[UITabBarController class]] && ![result isKindOfClass:[UINavigationController class]] && [result isKindOfClass:[UIViewController class]];
    //5. 进入递归循环,排除TabBarVC和NaviVC,以及进入PresentedVC继续递归
    while (!isViewController) {
        while ([result isKindOfClass:[UITabBarController class]]) {
            UITabBarController *tempVC = result;
            result = [tempVC selectedViewController];
        }
        while ([result isKindOfClass:[UINavigationController class]]) {
            UINavigationController *tempVC = result;
            result = [tempVC.viewControllers lastObject];
        }
        id presentedVC = [result presentedViewController];
        if (presentedVC) {
            result = presentedVC;
        }
        isViewController = ![result isKindOfClass:[UITabBarController class]] && ![result isKindOfClass:[UINavigationController class]] && [result isKindOfClass:[UIViewController class]];
    }

    return result;
}

该代码是加入了有Presented的VC就查到presented的,如果去掉present检查,可以查到除去model ViewController的第一个