How to center UIButton programmatically in UIImageView?

Question

I'm creating ViewCell programmatically and I want to center UIButton to UIImageView , so it would look like this:

 -----------------------------
|                             |
|                             |
|            Button           |
|                             |
|                             |
 -----------------------------

To achieve that first in init method I create UIImageView and UIButton :

let imageView = UIImageView()
imageView.contentMode = .scaleAspectFill
imageView.layer.masksToBounds = true
imageView.isUserInteractionEnabled = true

let button = UIButton(type: .custom)
button.setImage(UIImage(named: "button_image"), for: .normal)
button.contentMode = .center
button.frame = CGRect(x: 0, y: 0, width: 42, height: 42)

And then I add some constraints, in case of button and imageview I added these constraints:

button.addConstraint(NSLayoutConstraint(item: button, attribute: .centerX, relatedBy: .equal, toItem: imageView, attribute: .centerX, multiplier: 1, constant: 0))
button.addConstraint(NSLayoutConstraint(item: button, attribute: .centerY, relatedBy: .equal, toItem: imageView, attribute: .centerY, multiplier: 1, constant: 0))

But as result I always crash my app.

How can I achieve centered button?

Answer 1

尝试将translatesAutoresizingMaskIntoConstraints设置为false 。

Answer 2

视图完全加载后，执行此操作

button.center = imageView.center

Answer 3

Have you tried:

button.center = imageView.center 

It sets the center of the button frame to that of the imageview.

Answer 4

尝试.center属性，例如

myButton.center = self.image.center;

Answer 5

Try this

button.frame = imageV.frame