ios - 快速水平和垂直对齐图像

Question

我想对齐另一个图像(水平和垂直)以创建动画。动画很简单:心脏会在 Angry Bedou 的 Logo 内“振动”，但他必须在该图像中“居中”。

我正在尝试以下操作:

    func animate() {
    heartImg.frame = CGRectMake(angryBedousImg.frame.size.width / 2, angryBedousImg.frame.size.height / 2, heartImg.frame.size.width, heartImg.frame.size.height)

    let heartAnimation = CABasicAnimation(keyPath: "position")
    heartAnimation.duration = 0.09
    heartAnimation.repeatCount = .infinity
    heartAnimation.autoreverses = true
    heartAnimation.fromValue = NSValue(CGPoint: CGPointMake(heartImg.center.x - 1, heartImg.center.y))
    heartAnimation.toValue = NSValue(CGPoint: CGPointMake(heartImg.center.x + 1, heartImg.center.y))
    heartImg.layer.addAnimation(heartAnimation, forKey: "position")
        }

但是当我构建应用程序时它不会集中。动画有效，但对齐无效。我希望在纵向模式下的每台设备上都能进行对齐。

我查看了 Storyboard，图像很好。我做错了什么？

Answer 1

试试这个:

这将使您的 heartImage 居中于背景图像。

    let yourImage = UIImage(named: "YourImageName")
    let heartImg = UIImageView()
    heartImg.image = yourImage
    heartImg.translatesAutoresizingMaskIntoConstraints = false
    self.view.addSubview(heartImg)
    self.view.addConstraint(NSLayoutConstraint(item: heartImg, attribute: NSLayoutAttribute.centerX, relatedBy: NSLayoutRelation.equal, toItem: self.yourLogoImage, attribute: NSLayoutAttribute.centerX, multiplier: 1.0, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: heartImg, attribute: NSLayoutAttribute.centerY, relatedBy: NSLayoutRelation.equal, toItem: self.yourLogoImage, attribute: NSLayoutAttribute.centerY, multiplier: 1.0, constant: 0))
    self.view.addConstraint(NSLayoutConstraint(item: heartImg, attribute: NSLayoutAttribute.height, relatedBy: NSLayoutRelation.equal, toItem: nil, attribute: NSLayoutAttribute.notAnAttribute, multiplier: 1.0, constant: 40))
    self.view.addConstraint(NSLayoutConstraint(item: heartImg, attribute: NSLayoutAttribute.width, relatedBy: NSLayoutRelation.equal, toItem: nil, attribute: NSLayoutAttribute.notAnAttribute, multiplier: 1.0, constant: 40))