ios - Gif 未出现在手动输入的约束上

Question

下面的代码尝试在 ImageView 上加载 gif。当代码使用 Storyboard 上的约束时，此代码有效，但是当我编写 nslayout 约束时，gif 不会出现。没有运行时或编译错误，只是没有出现 gif。

let FIRE = UIImageView()

override func viewDidLoad() {
    super.viewDidLoad()

    FIRE.loadGif(name: "FIRE")

    view.addSubview(FIRE)

    FIRE.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
    FIRE.topAnchor.constraint(equalTo: view.topAnchor, constant: 20).isActive = true
    FIRE.widthAnchor.constraint(equalToConstant: 400).isActive = true
    FIRE.heightAnchor.constraint(equalToConstant: 80).isActive = true
}

Answer 1

您需要禁用 View 的自动调整大小掩码才能手动设置约束:

let imageView = UIImageView()


override func viewDidLoad() {
    super.viewDidLoad()

    // 1) turn off autoresizing mask
    imageView.translatesAutoresizingMaskIntoConstraints = false

    // 2) set contraints
    self.setupSubviews()

    // 3) update the view
    imageView.loadGif(name: "FIRE")

}

func setupSubviews() {
    self.view.addSubview(imageView)


    imageView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
    imageView.topAnchor.constraint(equalTo: view.topAnchor, constant: 20).isActive = true
    imageView.widthAnchor.constraint(equalToConstant: 400).isActive = true
    imageView.heightAnchor.constraint(equalToConstant: 80).isActive = true
}