How to scan Qr code from an image picked with UIImagePickerController in iOS

Question

I am able to scan qr code with camera without using any external libraries like ZBAR or ZXING.

Now what I actually want is to let the user upload an image from photo library and get the qr code scanned from that uploaded image.

I know how to use UIImagePickerController (used it before).

What I want to ask is that, How can I scan qr code from an uploaded image (without using the camera)

You can suggest some code (.h / .m files) that I can add in my project.

Please don't suggest me any external libraries like ZBAR or ZXING.

Answer 1

I know you might have found solution for this but i am replying to the post if my answer may help other for relevant question.

Here I am posting my code to ScanQRCode from image picked from gallery without using any Library.

func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {



    if let pickedImage = info[UIImagePickerControllerEditedImage] as? UIImage {
                 let detector:CIDetector=CIDetector(ofType: CIDetectorTypeQRCode, context: nil, options: [CIDetectorAccuracy:CIDetectorAccuracyHigh])

    let ciImage:CIImage = CIImage(image:pickedImage)!

    var qrCodeLink = ""

    let features=detector.featuresInImage(ciImage)

    for feature in features as! [CIQRCodeFeature] {

        qrCodeLink += feature.messageString
    }

    print(qrCodeLink)//Your result from QR Code
}

    dismissViewControllerAnimated(true, completion: nil)
}

Answer 2

Updated to swift 5 and more "swifty" way based on @Dev_Tandel response.
But for me .originalImage worked instead of .editedImage.

func imagePickerController(_ picker: UIImagePickerController,
                           didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {

    guard let pickedImage = info[UIImagePickerController.InfoKey.originalImage] as? UIImage,
        let detector = CIDetector(ofType: CIDetectorTypeQRCode,
                                  context: nil,
                                  options: [CIDetectorAccuracy: CIDetectorAccuracyHigh]),
        let ciImage = CIImage(image: pickedImage),
        let features = detector.features(in: ciImage) as? [CIQRCodeFeature] else { return }

    let qrCodeLink = features.reduce("") { $0 + ($1.messageString ?? "") }

    print(qrCodeLink)//Your result from QR Code
}

Answer 3

In Apple's iOS, a QR code reader is not natively included. Therefore there is no API from Apple you can use.

You have to rely either or third party SDKs or write your own code.