Crash on iOS 13 when permission denied

[xvrh]

The app crashes on the line 140 of QrReader.swift

    // catch?
    let input = try! AVCaptureDeviceInput.init(device: captureDevice)

on iOS 13 when the Camera permission if denied by the user.

2020-04-25 21:51:42.472234+0200 Runner[35675:9811013] Initialized TensorFlow Lite runtime.
Fatal error: 'try!' expression unexpectedly raised an error: Error Domain=AVFoundationErrorDomain Code=-11852 "Cannot use Back Camera" UserInfo={NSLocalizedFailureReason=This app is not authorized to use Back Camera., AVErrorDeviceKey=<AVCaptureFigVideoDevice: 0x10870d7c0 [Back Camera][com.apple.avfoundation.avcapturedevice.built-in_video:0]>, NSLocalizedDescription=Cannot use Back Camera}: file /Users/xavier/.pub-cache/hosted/pub.dartlang.org/qr_mobile_vision-1.0.1+1/ios/Classes/QrReader.swift, line 140
2020-04-25 21:51:42.494777+0200 Runner[35675:9811013] Fatal error: 'try!' expression unexpectedly raised an error: Error Domain=AVFoundationErrorDomain Code=-11852 "Cannot use Back Camera" UserInfo={NSLocalizedFailureReason=This app is not authorized to use Back Camera., AVErrorDeviceKey=<AVCaptureFigVideoDevice: 0x10870d7c0 [Back Camera][com.apple.avfoundation.avcapturedevice.built-in_video:0]>, NSLocalizedDescription=Cannot use Back Camera}: file /Users/xavier/.pub-cache/hosted/pub.dartlang.org/qr_mobile_vision-1.0.1+1/ios/Classes/QrReader.swift, line 140

[lovelessX]

I, too, am having this issue. Also on iOS 12.

[rohnsht]

Same here app crashes when permission is denied. Is there any fix for this?

[rohnsht]

The issue is there because let input = try! AVCaptureDeviceInput.init(device: captureDevice) this code throws an exception when the user denies Camera permission. Here is fix for this issue:

Inside QrReader.swift file that can be found inside Pods/Development Pods/qr_mobile_vision/.../classes make the following changes:

1. add throws to the constructor

init(targetWidth: Int, targetHeight: Int, textureHandler: TextureHandler, options: VisionBarcodeDetectorOptions, qrCallback: @escaping (_:String) -> Void) throws { 
 // ....
}

2. Remove ! from this line
   let input = try AVCaptureDeviceInput.init(device: captureDevice)

Now inside SwiftQrMobileVisionPlugin.swift modify this code:

do{
          reader = try QrReader(
            targetWidth: targetWidth,
            targetHeight: targetHeight,
            textureHandler: texture,
            options: options) { [unowned self] qr in
              self.channel.invokeMethod("qrRead", arguments: qr)
          }
      }catch {
        print(error.localizedDescription)
        result(FlutterError(code: "QRREADER_ERROR", message: "noPermission", details: ""))
        return
      }

[xvrh]

@rohnsht I opened a pull request with your instructions.

[rcagantas]

Any workaround on this? It's blocking a release.