Add child view controller to UINavigationController

I'm trying to add a child view controller to a UIViewController contained in a UINavigationController with this code:

- (void)buttonTapped:(id)sender
{
    MyChildController *viewController = [self.storyboard instantiateViewControllerWithIdentifier:@"MyChild"];
    [self addChildViewController:viewController];
    [self.view addSubview:viewController.view];
    [viewController didMoveToParentViewController:self];


    viewController.view.alpha = 0.0f;
    [UIView animateWithDuration:0.4 animations:^{
        viewController.view.alpha = 1.0f;
    }];
}

But this is the result:

As you can see the UINavigatioBar and the UIToolbar are still on top of the child view controller. How can I put the child view controller on top of all? I've already tried to replace the code with:

[self.navigationController addChildViewController:viewController];
    [self.navigationController.view addSubview:viewController.view];
    [viewController didMoveToParentViewController:self.navigationController];

But in this way the viewDidAppear:animated of the viewController doesn't get called. I don't know, why.

In your first view controller, do something like this:

- (IBAction)buttonClick:(id)sender
{
    SecondViewController *secondView = [self.storyboard instantiateViewControllerWithIdentifier:@"SecondViewController"];
    UIImage *blurryImage = [UIImage imageNamed:@"foo.jpeg"];
    secondView.imageView.image = blurryImage;
    [self.navigationController addChildViewController:secondView];
    secondView.view.frame = self.navigationController.view.frame;
    [self.navigationController.view addSubview:secondView.view];
}

Then in your second view controller, add the getter for your imageview:

-(UIImageView *)imageView
{
    if( _imageView == nil )
    {
        _imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, 548)];
        [self.view addSubview:_imageView];
    }
    return _imageView;
}