UIImageView Won't Show When ViewController Added As Subview - objective-c

Question

My main aim is to have one background for all of my ViewControllers. Every ViewController I have has a clear background.
To do this, I have made one UIViewController (called backgroundViewController) that will act as the subview to all my other ViewControllers. It has one UIImageView which displays this particular background. I will then add this backgroundViewController as a subview of all my other ViewControllers.
The problem is - this imageView won't show as a subview!
This is how I display the imageView:
- (void)viewDidLoad
{
if ([musicPlayer playbackState] == MPMusicPlaybackStateStopped) {
UIImage *artworkBackgroundView;
artworkBackgroundView = [UIImage imageNamed:#"noArtworkBackground"];
UIImage *effectImage = nil;
backgroundView.image = effectImage;
[backgroundView setImage:artworkBackgroundView];
backgroundView.image = effectImage;
}
}
- (void) handle_NowPlayingItemChanged: (id) notification
{
if ([musicPlayer playbackState] != MPMusicPlaybackStateStopped) {
// Get artwork for current now playing item
MPMediaItem *currentItem = [musicPlayer nowPlayingItem];
MPMediaItemArtwork *artwork = [currentItem valueForProperty: MPMediaItemPropertyArtwork];
UIImage *artworkBackgroundView = [artwork imageWithSize: CGSizeMake(618, 618)];
if (!artworkImage) {
artworkBackgroundView = [UIImage imageNamed:#"noArtworkBackground"];
artworkImage = [UIImage imageNamed:#"noArtwork"];
}
[backgroundView setImage:artworkBackgroundView];
}
}
As you can see, backgroundView changes each time the music player skips song.
To test that backgroundViewController does show as a subview, I added another imageView and changed its image to a static .png in Interface Builder, and that shows correctly as a subview.
This is how I make it a subview for other ViewControllers:
backgroundViewController *backgroundVC = [[backgroundViewController alloc] initWithNibName:#"backgroundViewController" bundle:nil];
[self.view insertSubview:backgroundVC.view atIndex:0];
What I want is the UIImageView called backgroundView to show up when it is being called as subview.
I have tested that backgroundView does change according to what song is playing, and it works correctly.
What am I doing wrong? backgroundView refuses to show up as a subview?! I've searched a ton about adding ViewControllers as subviews but I can't find a similar problem.
Any help would be much appreciated, thanks! :)

Answer 1

This worked for me:
backgroundViewController *backgroundVC = [[backgroundViewController alloc] initWithNibName:#"backgroundViewController" bundle:nil];
[self addChildViewController:backgroundVC];
[self.view addSubview:backgroundVC.view];
I found the solution here. I need to read more about 'Custom Containers'.