带导航的控制器上面再加个带导航的控制器，但第二个导航只从屏幕左边隔一定距离显示到右边的框

FilterViewController *filter = [[FilterViewControlleralloc]init];

        UINavigationController *nav = [[UINavigationControlleralloc]initWithRootViewController:filter];

        [nav.viewsetFrame:CGRectMake((40/375.0) * WIDTH, 0,WIDTH - (40/375.0) *WIDTH, HEIGHT)];

        [self.navigationControlleraddChildViewController:nav];

        [self.navigationController.viewaddSubview:nav.view];

在点击第二个导航的返回按钮时要

 [self.navigationController.viewremoveFromSuperview];

    [self.navigationControllerremoveFromParentViewController];

点击第一个控制器的空白时要记得

for (UIView *vvin self.navigationController.childViewControllers) {

        NSLog(@"%@",vv.class);

        if ([vvisKindOfClass:[UINavigationControllerclass]]) {

            UINavigationController *na = (UINavigationController *)vv;

            [na removeFromParentViewController];

            [na.viewremoveFromSuperview];

        }

    }