UIButton not respect Aspect Fill contentMode after resizing animation

Question

I am use auto layout. Following is the initial state of the view.

In the centre is a button contained in a view. The button has contentMode Aspect Fill, and the image is set as the background image of the button.

Then I use the following code to transform the view, which will enlarge the centre card to fill the screen, and move the image to the top of the view:

cardTrailingSpaceConstraint.constant = 0 cardLeadingSpaceConstraint.constant = 0 cardView.removeConstraint(cardAspectRatioConstraint) let cardHeightConstraint = NSLayoutConstraint(item: cardView, attribute: .Height, relatedBy: .Equal, toItem: view, attribute: .Height, multiplier: 1.0, constant: 0) view.addConstraint(cardHeightConstraint)  dishImageButton.removeConstraint(dishButtonBottomSpaceConstraint) let dishButtonHeightConstraint = NSLayoutConstraint(item: dishImageButton, attribute: .Height, relatedBy: .Equal, toItem: cardView, attribute: .Height, multiplier: 0.2, constant: 0) cardView.addConstraint(dishButtonHeightConstraint)  cardView.setNeedsUpdateConstraints() UIView.animateWithDuration(0.7, delay: 0, usingSpringWithDamping: 0.7, initialSpringVelocity: 0.7, options: nil, animations: { [unowned self] () -> Void in     self.cardHeader.alpha = 0     self.cardView.layer.cornerRadius = 0     self.cardView.layoutIfNeeded()      }) { [unowned self] (finished) -> Void in          } 

The result is:

However, it is not what I want. The button is not respecting the contentMode and the image then get stretched.

Can anyone tell me how to maintain the Aspect Fill contentMode of the button?

Answer 1

1. Set the button type to UIButtonTypeCustom (“Custom” in a storyboard or xib).
2. Set the button's image, not the button's background image.
3. In viewDidLoad, set button.imageView.contentMode to UIViewContentMode.ScaleAspectFill.

Answer 2

Swift 3

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Going off of Rob's answer:

    let btn = UIButton(frame: CGRect(x: 0, y: 0, width: 80, height: 30))     btn.setImage(UIImage(named: "albumsBtn"), for: UIControlState.normal)     btn.imageView?.contentMode = UIViewContentMode.scaleAspectFit     btn.addTarget(self.navigationController, action: #selector(CustomGalleryViewController.showAlbums(_:)), for:  UIControlEvents.touchUpInside)     let item = UIBarButtonItem(customView: btn)     self.navigationItem.leftBarButtonItem = item