MKAnnotationView 图像切换的转换问题答案

【问题标题】：MKAnnotationView image toggling's transition issueMKAnnotationView 图像切换的转换问题
【发布时间】：2019-11-21 22:20:40
【问题描述】：

MKAnnotationView 有 2 个图像状态，它们是 selected 和 deselected。问题是这两种状态之间的过渡很差。网上没有太多关于此的内容，而且我通常在转换时遇到问题。

这是我正在使用的MKAnnotationView：

class CustomPinView: MKAnnotationView {
    func updateImage() {
        guard let mapAnnotation = annotation as? MapAnnotation else {return}
        if let selectedImageName = mapAnnotation.selectedImageName, isSelected {
            image = UIImage(inCurrentBundleWithName: selectedImageName)
        } else if let imageName = mapAnnotation.imageName {
            image = UIImage(inCurrentBundleWithName: imageName)
        } else {
            image = nil
        }
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)
        updateImage()
    }

    override var annotation: MKAnnotation? {
        didSet {
            updateImage()
        }
  }
}

【问题讨论】：

标签： swift mapkit mkannotation mkannotationview

【解决方案1】：

我将updateImage 函数更新为如下所示：

private func updateImage() {
        CATransaction.begin()
        CATransaction.setAnimationDuration(0.2)
        CATransaction.setAnimationTimingFunction(CAMediaTimingFunction(name: .easeOut))
        UIView.animate(withDuration: 0.2, delay: 0, options: .curveEaseIn, animations: {
            guard let mapAnnotation = self.annotation as? MapAnnotation else {return}
            if let selectedImageName = mapAnnotation.selectedImageName, self.isSelected {
                self.image = UIImage(inCurrentBundleWithName: selectedImageName)
                self.layer.anchorPoint = CGPoint(x: 0.5, y: 0.6)
            } else if let imageName = mapAnnotation.imageName {
                self.image = UIImage(inCurrentBundleWithName: imageName)
                self.layer.anchorPoint = CGPoint(x: 0.5, y: 0.5)
            } else {
                self.image = nil
            }
            self.centerOffset = CGPoint(x: 0.5, y: 0.5)
        }, completion: nil)
        CATransaction.commit()
    }

这是从这里的答案中提取的：https://stackoverflow.com/a/54431257/4114335

【讨论】：