Swift

Question

我想为所有视图控制器设置相同的背景图像。这是我尝试过的：

let backgroundImage = UIImageView(frame: UIScreen.main.bounds)
backgroundImage.image = UIImage(named: "bg_name.png")
backgroundImage.contentMode = UIViewContentMode.scaleAspectFill
self.view.insertSubview(backgroundImage, at: 0)

但这只能通过在任何地方复制粘贴来实现。什么是更好的方法呢？

Answer 1

如果您希望在所有视图控制器中拥有相同的背景图像，那么一个选项是创建自定义基础ViewController类，并让所有其他类继承该类。例如 -

class BackgroundImageViewController: ViewController {

 override func viewDidLoad(_animated: Bool) {
    super.viewDidLoad(animated: animated)
    let backgroundImage = UIImageView(frame: UIScreen.main.bounds)
    backgroundImage.image = UIImage(named: "bg_name.png")
    backgroundImage.contentMode = UIViewContentMode.scaleAspectFill
    self.view.insertSubview(backgroundImage, at: 0)
  }

}

然后 -

class AnotherViewController: BackgroundImageViewController {

  // Your normal view controller stuff

}

Answer 2

您可以创建视图控制器类的扩展

extension UIViewController {

    /// This function sets an image as the background of the view controller
    ///
    /// - Parameters:
    ///   - imageName: name of image
    ///   - contentMode:
    ///          .scaleAspectFill
    ///          .scaleAspectFit
    ///          .scaleToFill
    func setBackgroundImage(_ imageName: String, contentMode: UIViewContentMode) {
        let backgroundImage = UIImageView(frame: self.view.bounds)
        backgroundImage.image = UIImage(named: imageName)
        backgroundImage.contentMode = contentMode
        self.view.insertSubview(backgroundImage, at: 0)
    }

}

在任何UIViewController类中的用法

override func viewDidLoad() {
    super.viewDidLoad()

    self.setBackgroundImage("name_image", contentMode: .scaleAspectFit)
}