How do I change UIImageView image in view controller in traitCollectionDidChange

I want the image in my UIImageView to us a different image file that's cropped to correctly fill the landscape mode upon the orientation changing from portrait to landscape. All of the following code is defined in a class that extends UIViewController.

The following function is definitely being called when the phone rotates because my printf function is printing to the output.

- (void) traitCollectionDidChange: (UITraitCollection *) previousTraitCollection {
[super traitCollectionDidChange: previousTraitCollection];
if ((self.traitCollection.verticalSizeClass != previousTraitCollection.verticalSizeClass)
    || (self.traitCollection.horizontalSizeClass != previousTraitCollection.horizontalSizeClass)) {
    printf("Orientation Change!\n");
    UIImage * newImage = [UIImage imageNamed: @"landscape-image"];
    [self.imageView setImage:newImage];
}

}

I defined the property imageView in my .h file as follows:

@property (nonatomic, nonnull, readonly) UIImageView * imageView;

And I initialize the imageView as follows:

UIImage * image = [UIImage imageNamed:@“portrait-image”];

UIImageView * _imageView = [[UIImageView alloc] initWithImage:image];

_imageView.contentMode = UIViewContentModeScaleAspectFill;

_imageView.translatesAutoresizingMaskIntoConstraints = NO;

[pageView addSubview:_imageView];

This does not work for me though. When I change the orientation, the imageView image stays the same and zooms in like it normally does. Since the traitCollectionDidChange function is being called when the phone rotates, I assume the issue must be with how I’m changing the image. I’m relatively new to iOS development so I could just be missing something important for updating UIImageViews. Any help is appreciated.

#ios #objective-c #xcode