// 1.加载Gif图片, 并且转成Data类型

guard let path = Bundle.main.path(forResource: "demoGif.gif", ofType: nil)

guard let data = NSData(contentsOfFile: path) else { return }

// 2.从data中读取数据: 将data转成CGImageSource对象

guard let imageSource = CGImageSourceCreateWithData(data, nil) else { return }

let imageCount = CGImageSourceGetCount(imageSource)

// 3.遍历所有图片

var images = [UIImage]()

var totalDuration : TimeInterval = 0

for i in 0..<imageCount {

    //取出图片

guard let cgImage = CGImageSourceCreateImageAtIndex(imageSource, i, nil) else { continue }

let image = UIImage(cgImage: cgImage)

if i == 0 {

imageView.image = image

}

images.append(image)

  // 取出持续的时间

guard let properties = CGImageSourceCopyPropertiesAtIndex(imageSource, i, nil) as? NSDictionary else { continue }

guard let gifDict = properties[kCGImagePropertyGIFDictionary] as? NSDictionary else { continue }

guard let frameDuration = gifDict[kCGImagePropertyGIFDelayTime] as? NSNumber else { continue }

totalDuration += frameDuration.doubleValue

}

// 4.设置imageView的属性

imageView.animationImages = images

imageView.animationDuration = totalDuration

imageView.animationRepeatCount = 0

// 5.开始播放

imageView.startAnimating()