斯威夫特5

编码

func convertImageToBase64String (img: UIImage) -> String {
    return img.jpegData(compressionQuality: 1)?.base64EncodedString() ?? ""
}

解码

func convertBase64StringToImage (imageBase64String:String) -> UIImage {
    let imageData = Data(base64Encoded: imageBase64String)
    let image = UIImage(data: imageData!)
    return image!
}

注意:在xcode 10.2中测试

斯威夫特4

编码

func convertImageToBase64String (img: UIImage) -> String {
    let imageData:NSData = UIImageJPEGRepresentation(img, 0.50)! as NSData //UIImagePNGRepresentation(img)
    let imgString = imageData.base64EncodedString(options: .init(rawValue: 0))
    return imgString
}

解码

func convertBase64StringToImage (imageBase64String:String) -> UIImage {
    let imageData = Data.init(base64Encoded: imageBase64String, options: .init(rawValue: 0))
    let image = UIImage(data: imageData!)
    return image
}

注意:在xcode 9.4.1中测试

我尝试了所有的解决方案，没有一个对我有效(使用Swift 4)，这是对我有效的解决方案，如果将来有人面临同样的问题。

let temp = base64String.components(separatedBy: ",")
let dataDecoded : Data = Data(base64Encoded: temp[1], options: 
 .ignoreUnknownCharacters)!
let decodedimage = UIImage(data: dataDecoded)

yourImage.image = decodedimage

斯威夫特5号，Xcode 10号。

let imageData = UIImage（named：“imagename”）.pngData（）？.base64EncodedString（选项： .lineLength64Characters） 打印（图像数据）

4.2扩展方法

extension UIImage {
    func toBase64() -> String? {
        guard let imageData = self.pngData() else { return nil }
        return imageData.base64EncodedString(options: .lineLength64Characters)
    }
}

XCode 9.1和Swift 4.0

//
// Convert UIImage to a base64 representation
//
class func convertImageToBase64(image: UIImage) -> String {
    let imageData = UIImagePNGRepresentation(image)!
    return imageData.base64EncodedString(options: Data.Base64EncodingOptions.lineLength64Characters)
}

//
// Convert a base64 representation to a UIImage
//
class func convertBase64ToImage(imageString: String) -> UIImage {
    let imageData = Data(base64Encoded: imageString, options: Data.Base64DecodingOptions.ignoreUnknownCharacters)!
    return UIImage(data: imageData)!
}

@implementation UIImage (Extended)

- (NSString *)base64String {
    NSData * data = [UIImagePNGRepresentation(self) base64EncodedDataWithOptions:NSDataBase64Encoding64CharacterLineLength];
    return [NSString stringWithUTF8String:[data bytes]];
}

@end

在Swift 3.0中

func decodeBase64(toImage strEncodeData: String) -> UIImage {

    let dataDecoded  = NSData(base64Encoded: strEncodeData, options: NSData.Base64DecodingOptions.ignoreUnknownCharacters)!
    let image = UIImage(data: dataDecoded as Data)
    return image!

}