iOS AppDelegate实现跳转ViewControlle

也是在项目中遇到这样的需求，就是接收到远程推送通知时，如何调转到相应的通知页面。

直接上代码吧，比较简单，就是获取根控制器，然后Push就可以了

主要是如何的AppDelegate中获取根控制器，下面就提供两种方法，都是获取根控制器的

实现方法

就是在获取到最顶层控制器`[self topViewController]` ，直接
[vc.navigationController pushViewController:nextVC animated:YES];

代码一

/// 获取最顶层控制器
- (UIViewController *)topViewController {
    UIViewController *resultVC;
    resultVC = [self _topViewController:[[UIApplication sharedApplication].keyWindow rootViewController]];
    while (resultVC.presentedViewController) {
        resultVC = [self _topViewController:resultVC.presentedViewController];
    }
    return resultVC;
}

- (UIViewController *)_topViewController:(UIViewController *)vc {
    if ([vc isKindOfClass:[UINavigationController class]]) {
        return [self _topViewController:[(UINavigationController *)vc topViewController]];
    } else if ([vc isKindOfClass:[UITabBarController class]]) {
        return [self _topViewController:[(UITabBarController *)vc selectedViewController]];
    } else {
        return vc;
    }
    return nil;
}

代码二

- (UIViewController *) topViewController {
    UIViewController *result = nil;
    UIWindow * window = [[UIApplication sharedApplication] keyWindow];
    //app默认windowLevel是UIWindowLevelNormal，如果不是，找到UIWindowLevelNormal的
    if (window.windowLevel != UIWindowLevelNormal)
    {
        NSArray *windows = [[UIApplication sharedApplication] windows];
        for(UIWindow * tmpWin in windows)
        {
            if (tmpWin.windowLevel == UIWindowLevelNormal)
            {
                window = tmpWin;
                break;
            }
        }
    }
    id  nextResponder = nil;
    UIViewController *appRootVC = window.rootViewController;
    //    如果是present上来的appRootVC.presentedViewController 不为nil
    if (appRootVC.presentedViewController) {
        nextResponder = appRootVC.presentedViewController;
    }else{
        UIView *frontView = [[window subviews] objectAtIndex:0];
        nextResponder = [frontView nextResponder];  
    }
    
    if ([nextResponder isKindOfClass:[UITabBarController class]]){
        UITabBarController * tabbar = (UITabBarController *)nextResponder;
        UINavigationController * nav = (UINavigationController *)tabbar.viewControllers[tabbar.selectedIndex];
        //        UINavigationController * nav = tabbar.selectedViewController ; 上下两种写法都行
        result = nav.childViewControllers.lastObject;
        
    }else if ([nextResponder isKindOfClass:[UINavigationController class]]){
        UIViewController * nav = (UIViewController *)nextResponder;
        result = nav.childViewControllers.lastObject;
    }else{
        result = nextResponder;
    }
    
    return result;
}