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Getting an error when converting UIImage to NSSString via NSData

I'm trying to convert my UIImage from a UIImageView to a string as the data is stored as Base64. I'm using the method below to convert the image but it falls over when trying to update convertedStr. 

func convertImg() {
    let imageData: NSData = UIImagePNGRepresentation(imageView.image!)! as NSData
    convertedStr = NSString(data: imageData as Data, encoding: String.Encoding.utf8.rawValue)!
}

This function is about version 10 as I've tried different ways but the result is always the same. The error returned is

'fatal error: unexpectedly found nil while unwrapping an Optional value' and

'function signature specialization ) -> () to @callee_owned (@unowned Swift.UnsafeBufferPointer) -> (@out ()), Argument Types : [@callee_owned (@unowned Swift.UnsafeBufferPointer) -> ()]> of generic specialization of Swift.StaticString.withUTF8Buffer ((Swift.UnsafeBufferPointer) -> A) -> A'

Could it be that the method I'm using requires a png file and won't work with UIImage?

Solution

  • In Swift

    Encode in swift 2.0 and lower

    let image : UIImage = UIImage(named:"imageNameHere")!
//Now use image to create into NSData format
let imageData:NSData = UIImagePNGRepresentation(image)!

 let strBase64:String = imageData.base64EncodedStringWithOptions(.Encoding64CharacterLineLength)

    Decode

    let dataDecoded:NSData = NSData(base64EncodedString: strBase64, options: NSDataBase64DecodingOptions(rawValue: 0))!
let decodedimage:UIImage = UIImage(data: dataDecoded)!
print(decodedimage)
yourImageView.image = decodedimage