iOS任何地方拿到当前控制器

在子控件里，不是在控制器中(含导航)，不能push\n
NSObject加法声明、减法实现，方便调用！

@interface NSObject (currentViewController)
+ (BNBaseViewController *)currentViewController;
@end

@implementation NSObject (currentViewController)
- (BNBaseViewController *)currentViewController {
    BNBaseNavigationController *rootNavController = (BNBaseNavigationController *)[UIApplication sharedApplication].delegate.window.rootViewController;

    if ([rootNavController isKindOfClass:[BNBaseNavigationController class]]) {
        BNBaseViewController *currentVC = rootNavController.viewControllers.lastObject;
        return currentVC;
    } else {
        return nil;
    }
}

使用

+ (void)checkUserInfo {
    AccountSetViewController *vc = [[AccountSetViewController alloc] init];
    [[self currentViewController].navigationController pushViewController:vc animated:YES];
}