Added future to functions. Changed min SDK to 2.6.0.

android/src/main/kotlin/net/touchcapture/qr/flutterqr/FlutterQrPlugin.kt

@@ -7,6 +7,7 @@ import io.flutter.embedding.engine.plugins.FlutterPlugin
 import io.flutter.embedding.engine.plugins.activity.ActivityAware
 import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding
 import io.flutter.plugin.common.BinaryMessenger
+import io.flutter.plugin.common.MethodChannel
 import io.flutter.plugin.common.PluginRegistry
 import io.flutter.plugin.platform.PlatformViewRegistry
 
@@ -63,7 +64,6 @@ class FlutterQrPlugin : FlutterPlugin, ActivityAware {
     inner class CameraRequestPermissionsListener : PluginRegistry.RequestPermissionsResultListener {
         override fun onRequestPermissionsResult(id: Int, permissions: Array<String>, grantResults: IntArray): Boolean {
             if (id == Shared.CAMERA_REQUEST_ID && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
-                Shared.cameraPermissionContinuation?.run()
                 return true
             }
             return false

android/src/main/kotlin/net/touchcapture/qr/flutterqr/QRView.kt

@@ -10,6 +10,7 @@ import android.view.View
 import com.google.zxing.ResultPoint
 import android.hardware.Camera.CameraInfo
 import android.os.Build
+import com.google.zxing.BarcodeFormat
 import com.journeyapps.barcodescanner.BarcodeCallback
 import com.journeyapps.barcodescanner.BarcodeResult
 import com.journeyapps.barcodescanner.BarcodeView
@@ -22,8 +23,22 @@ class QRView(messenger: BinaryMessenger, id: Int, private val context: Context,
 
     private var isTorchOn: Boolean = false
     private var barcodeView: BarcodeView? = null
-    private var requestingPermission = false
     private val channel: MethodChannel
+    var allowedBarcodeTypes = mutableListOf<BarcodeFormat>()
+
+    private val qrCodeTypes = mapOf(
+            0 to BarcodeFormat.AZTEC,
+            1 to BarcodeFormat.CODE_128,
+            2 to BarcodeFormat.CODE_39,
+            3 to BarcodeFormat.CODE_93,
+            4 to BarcodeFormat.DATA_MATRIX,
+            5 to BarcodeFormat.EAN_13,
+            6 to BarcodeFormat.EAN_8,
+            7 to BarcodeFormat.ITF,
+            8 to BarcodeFormat.PDF_417,
+            9 to BarcodeFormat.QR_CODE,
+            10 to BarcodeFormat.UPC_E
+    )
 
     init {
         checkAndRequestPermission(null)
@@ -65,68 +80,121 @@ class QRView(messenger: BinaryMessenger, id: Int, private val context: Context,
     }
 
     override fun onMethodCall(call: MethodCall, result: MethodChannel.Result) {
-        when(call.method){
-            "startScan" -> {
-                startScan()
-            }
-            "stopScan" -> {
-                stopScan()
-            }
-            "flipCamera" -> {
-                flipCamera()
-            }
-            "toggleFlash" -> {
-                toggleFlash()
-            }
-            "pauseCamera" -> {
-                pauseCamera()
-            }
-            "resumeCamera" -> {
-                resumeCamera()
-            }
+        when(call.method) {
+            "startScan" -> startScan()
+            "stopScan" -> stopScan()
+            "flipCamera" -> flipCamera(result)
+            "toggleFlash" -> toggleFlash(result)
+            "pauseCamera" -> pauseCamera(result)
+            "resumeCamera" -> resumeCamera(result)
+            "requestPermissions" -> checkAndRequestPermission(result)
+            "getCameraInfo" -> getCameraInfo(result)
+            "getFlashInfo" -> getFlashInfo(result)
+//            "showNativeAlertDialog" -> showNativeAlertDialog(result)
+            "getSystemFeatures" -> getSystemFeatures(result)
+            "setAllowedBarcodeFormats" -> setBarcodeFormats(call.arguments as List<Int>, result)
+            else -> result.notImplemented()
         }
     }
 
-    private fun flipCamera() {
-        barcodeView?.pause()
-        val settings = barcodeView?.cameraSettings
+    private fun getCameraInfo(result: MethodChannel.Result) {
+        if (barcodeView == null) {
+            return barCodeViewNotSet(result)
+        }
+        result.success(barcodeView!!.cameraSettings.requestedCameraId)
+    }
+
+    private fun flipCamera(result: MethodChannel.Result) {
+        if (barcodeView == null) {
+            return barCodeViewNotSet(result)
+        }
+        barcodeView!!.pause()
+        val settings = barcodeView!!.cameraSettings
 
-        if(settings?.requestedCameraId == CameraInfo.CAMERA_FACING_FRONT)
+        if(settings.requestedCameraId == CameraInfo.CAMERA_FACING_FRONT)
             settings.requestedCameraId = CameraInfo.CAMERA_FACING_BACK
         else
-            settings?.requestedCameraId = CameraInfo.CAMERA_FACING_FRONT
+            settings.requestedCameraId = CameraInfo.CAMERA_FACING_FRONT
 
-        barcodeView?.cameraSettings = settings
-        barcodeView?.resume()
+        barcodeView!!.cameraSettings = settings
+        barcodeView!!.resume()
+        result.success(settings.requestedCameraId)
     }
 
-    private fun toggleFlash() {
+    private fun getFlashInfo(result: MethodChannel.Result) {
+        if (barcodeView == null) {
+            return barCodeViewNotSet(result)
+        }
+        result.success(isTorchOn)
+    }
+
+    private fun toggleFlash(result: MethodChannel.Result) {
+        if (barcodeView == null) {
+            return barCodeViewNotSet(result)
+        }
+
         if (hasFlash()) {
-            barcodeView?.setTorch(!isTorchOn)
+            barcodeView!!.setTorch(!isTorchOn)
             isTorchOn = !isTorchOn
+            result.success(isTorchOn)
+        } else {
+            result.error("404", "This device doesn't support flash", null)
         }
 
     }
 
-    private fun pauseCamera() {
+    private fun pauseCamera(result: MethodChannel.Result) {
+        if (barcodeView == null) {
+            return barCodeViewNotSet(result)
+        }
         if (barcodeView!!.isPreviewActive) {
-            barcodeView?.pause()
+            barcodeView!!.pause()
         }
+        result.success(true)
     }
 
-    private fun resumeCamera() {
+    private fun resumeCamera(result: MethodChannel.Result) {
+        if (barcodeView == null) {
+            return barCodeViewNotSet(result)
+        }
         if (!barcodeView!!.isPreviewActive) {
-            barcodeView?.resume()
+            barcodeView!!.resume()
         }
+        result.success(true)
     }
 
     private fun hasFlash(): Boolean {
-        return context.packageManager
-                .hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH)
+        return hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH)
+    }
+
+    private fun hasBackCamera(): Boolean {
+        return hasSystemFeature(PackageManager.FEATURE_CAMERA)
+    }
+
+    private fun hasFrontCamera(): Boolean {
+        return hasSystemFeature(PackageManager.FEATURE_CAMERA_FRONT)
+    }
+
+    private fun hasSystemFeature(feature: String): Boolean {
+        return Shared.activity!!.packageManager
+                .hasSystemFeature(feature)
+    }
+
+    private fun barCodeViewNotSet(result: MethodChannel.Result) {
+        result.error("404", "No barcode view found", null)
     }
 
     override fun getView(): View {
         return initBarCodeView()?.apply {
+            if (!hasBackCamera()) {
+                if (!hasFrontCamera()) {
+                    // No camera available!
+                } else {
+                    this.cameraSettings.requestedCameraId = CameraInfo.CAMERA_FACING_FRONT
+                }
+            } else {
+                this.cameraSettings.requestedCameraId = CameraInfo.CAMERA_FACING_BACK
+            }
             resume()
         }!!
     }
@@ -145,11 +213,14 @@ class QRView(messenger: BinaryMessenger, id: Int, private val context: Context,
         barcodeView?.decodeContinuous(
                 object : BarcodeCallback {
                     override fun barcodeResult(result: BarcodeResult) {
-                        val code = mapOf(
-                                "code" to result.text,
-                                "type" to result.barcodeFormat.name,
-                                "rawBytes" to result.rawBytes)
-                        channel.invokeMethod("onRecognizeQR", code)
+                        if (allowedBarcodeTypes.size == 0 || allowedBarcodeTypes.contains(result.barcodeFormat)) {
+                            val code = mapOf(
+                                    "code" to result.text,
+                                    "type" to result.barcodeFormat.name,
+                                    "rawBytes" to result.rawBytes)
+                            channel.invokeMethod("onRecognizeQR", code)
+                        }
+
                     }
 
                     override fun possibleResultPoints(resultPoints: List<ResultPoint>) {}
@@ -161,35 +232,55 @@ class QRView(messenger: BinaryMessenger, id: Int, private val context: Context,
         barcodeView?.stopDecoding()
     }
 
+    private fun getSystemFeatures(result: MethodChannel.Result) {
+        try {
+            result.success(mapOf("hasFrontCamera" to hasFrontCamera(),
+                    "hasBackCamera" to hasBackCamera(), "hasFlash" to hasFlash(),
+                    "activeCamera" to barcodeView?.cameraSettings?.requestedCameraId))
+        } catch (e: Exception) {
+            result.error(null, null, null)
+        }
+    }
+
+    private fun setBarcodeFormats(arguments: List<Int>, result: MethodChannel.Result) {
+        try {
+            allowedBarcodeTypes.clear()
+            arguments.forEach {
+                allowedBarcodeTypes.add(qrCodeTypes[it]!!)
+            }
+            result.success(true)
+        } catch (e: java.lang.Exception) {
+            result.error(null, null, null)
+        }
+    }
+
+//    private fun showNativeAlertDialog(result: MethodChannel.Result) {
+//        AlertDialog.Builder(context)
+//                .setTitle("Scanning Unavailable")
+//                .setMessage("This app does not have permission to access the camera")
+//                .setPositiveButton(R.string.ok, null)
+//                .setCancelable(false)
+//                .setIcon(R.drawable.ic_dialog_alert)
+//                .show()
+//        result.success(true)
+//    }
+
     private fun hasCameraPermission(): Boolean {
         return Build.VERSION.SDK_INT < Build.VERSION_CODES.M ||
                 Shared.activity?.checkSelfPermission(Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED
     }
 
     private fun checkAndRequestPermission(result: MethodChannel.Result?) {
-        if (Shared.cameraPermissionContinuation != null) {
-            result?.error("cameraPermission", "Camera permission request ongoing", null)
-        }
-
-        Shared.cameraPermissionContinuation = Runnable {
-            Shared.cameraPermissionContinuation = null
-            if (!hasCameraPermission()) {
-                result?.error(
-                        "cameraPermission", "MediaRecorderCamera permission not granted", null)
-                return@Runnable
-            }
-        }
-
-        requestingPermission = false
-        if (hasCameraPermission()) {
-            Shared.cameraPermissionContinuation?.run()
-        } else {
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-                requestingPermission = true
+        when {
+            hasCameraPermission() -> result?.success(true)
+            Build.VERSION.SDK_INT >= Build.VERSION_CODES.M -> {
                 Shared.activity?.requestPermissions(
                         arrayOf(Manifest.permission.CAMERA),
                         Shared.CAMERA_REQUEST_ID)
             }
+            else -> {
+                result?.error("cameraPermission", "Platform Version to low for camera permission check", null)
+            }
         }
     }
 }

android/src/main/kotlin/net/touchcapture/qr/flutterqr/Shared.kt

@@ -5,5 +5,4 @@ import android.app.Activity
 object Shared {
     const val CAMERA_REQUEST_ID = 513469796
     var activity: Activity? = null
-    var cameraPermissionContinuation: Runnable? = null
 }

example/lib/main.dart

@@ -6,11 +6,6 @@ import 'package:qr_code_scanner/qr_code_scanner.dart';
 
 void main() => runApp(MaterialApp(home: QRViewExample()));
 
-const flashOn = 'FLASH ON';
-const flashOff = 'FLASH OFF';
-const frontCamera = 'FRONT CAMERA';
-const backCamera = 'BACK CAMERA';
-
 class QRViewExample extends StatefulWidget {
   const QRViewExample({
     Key key,
@@ -21,9 +16,8 @@ class QRViewExample extends StatefulWidget {
 }
 
 class _QRViewExampleState extends State<QRViewExample> {
+
   Barcode result;
-  var flashState = flashOn;
-  var cameraState = frontCamera;
   QRViewController controller;
   final GlobalKey qrKey = GlobalKey(debugLabel: 'QR');
 
@@ -64,44 +58,33 @@ class _QRViewExampleState extends State<QRViewExample> {
                       Container(
                         margin: EdgeInsets.all(8),
                         child: RaisedButton(
-                          onPressed: () {
-                            if (controller != null) {
-                              controller.toggleFlash();
-                              if (_isFlashOn(flashState)) {
-                                setState(() {
-                                  flashState = flashOff;
-                                });
-                              } else {
-                                setState(() {
-                                  flashState = flashOn;
-                                });
-                              }
-                            }
-                          },
-                          child:
-                              Text(flashState, style: TextStyle(fontSize: 20)),
-                        ),
+                            onPressed: () => setState(() {
+                                  controller?.toggleFlash();
+                                }),
+                            child: FutureBuilder(
+                              future: controller?.getFlashStatus(),
+                              builder: (context, snapshot) {
+                                return Text('Flash: ${snapshot.data}');
+                              },
+                            )),
                       ),
                       Container(
                         margin: EdgeInsets.all(8),
                         child: RaisedButton(
-                          onPressed: () {
-                            if (controller != null) {
-                              controller.flipCamera();
-                              if (_isBackCamera(cameraState)) {
-                                setState(() {
-                                  cameraState = frontCamera;
-                                });
-                              } else {
-                                setState(() {
-                                  cameraState = backCamera;
-                                });
-                              }
-                            }
-                          },
-                          child:
-                              Text(cameraState, style: TextStyle(fontSize: 20)),
-                        ),
+                            onPressed: () => setState(() {
+                                  controller?.flipCamera();
+                                }),
+                            child: FutureBuilder(
+                              future: controller?.getCameraInfo(),
+                              builder: (context, snapshot) {
+                                if (snapshot.data != null) {
+                                  return Text(
+                                      'Camera facing ${describeEnum(snapshot.data)}');
+                                } else {
+                                  return Text('loading');
+                                }
+                              },
+                            )),
                       )
                     ],
                   ),
@@ -138,14 +121,6 @@ class _QRViewExampleState extends State<QRViewExample> {
     );
   }
 
-  bool _isFlashOn(String current) {
-    return flashOn == current;
-  }
-
-  bool _isBackCamera(String current) {
-    return backCamera == current;
-  }
-
   Widget _buildQrView(BuildContext context) {
     // For this example we check how width or tall the device is and change the scanArea and overlay accordingly.
     var scanArea = (MediaQuery.of(context).size.width < 400 ||
@@ -169,7 +144,9 @@ class _QRViewExampleState extends State<QRViewExample> {
   }
 
   void _onQRViewCreated(QRViewController controller) {
-    this.controller = controller;
+    setState(() {
+      this.controller = controller;
+    });
     controller.scannedDataStream.listen((scanData) {
       setState(() {
         result = scanData;

ios/Classes/QRView.swift

@@ -15,6 +15,22 @@ public class QRView:NSObject,FlutterPlatformView {
     var channel: FlutterMethodChannel
     var cameraFacing: MTBCamera
     
+    var allowedBarcodeTypes: Array<AVMetadataObject.ObjectType> = []
+    
+    var QRCodeTypes = [
+          0: AVMetadataObject.ObjectType.aztec,
+          1: AVMetadataObject.ObjectType.code128,
+          2: AVMetadataObject.ObjectType.code39,
+          3: AVMetadataObject.ObjectType.code93,
+          4: AVMetadataObject.ObjectType.dataMatrix,
+          5: AVMetadataObject.ObjectType.ean13,
+          6: AVMetadataObject.ObjectType.ean8,
+          7: AVMetadataObject.ObjectType.interleaved2of5,
+          8: AVMetadataObject.ObjectType.pdf417,
+          9: AVMetadataObject.ObjectType.qr,
+          10: AVMetadataObject.ObjectType.upce
+         ]
+    
     public init(withFrame frame: CGRect, withRegistrar registrar: FlutterPluginRegistrar, withId id: Int64, params: Dictionary<String, Any>){
         self.registrar = registrar
         previewView = UIView(frame: frame)
@@ -36,13 +52,23 @@ public class QRView:NSObject,FlutterPlatformView {
                 case "startScan":
                     self?.startScan(result)
                 case "flipCamera":
-                    self?.flipCamera()
+                    self?.flipCamera(result)
                 case "toggleFlash":
-                    self?.toggleFlash()
+                    self?.toggleFlash(result)
                 case "pauseCamera":
-                    self?.pauseCamera()
+                    self?.pauseCamera(result)
                 case "resumeCamera":
-                    self?.resumeCamera()
+                    self?.resumeCamera(result)
+                case "getCameraInfo":
+                    self?.getCameraInfo(result)
+                case "getFlashInfo":
+                    self?.getFlashInfo(result)
+                case "showNativeAlertDialog":
+                    self?.showNativeAlertDialog(result)
+                case "getSystemFeatures":
+                    self?.getSystemFeatures(result)
+                case "setAllowedBarcodeFormats":
+                    self?.setBarcodeFormats(call.arguments as! Array<Int>, result)
                 default:
                     result(FlutterMethodNotImplemented)
                     return
@@ -108,7 +134,10 @@ public class QRView:NSObject,FlutterPlatformView {
                                 }
                                 guard let stringValue = code.stringValue else { continue }
                                 let result = ["code": stringValue, "type": typeString]
-                                self?.channel.invokeMethod("onRecognizeQR", arguments: result)
+                                if self!.allowedBarcodeTypes.count == 0 || self!.allowedBarcodeTypes.contains(code.type) {
+                                    self?.channel.invokeMethod("onRecognizeQR", arguments: result)
+                                }
+                                
                             }
                         }
                     })
@@ -131,35 +160,106 @@ public class QRView:NSObject,FlutterPlatformView {
         }
     }
     
-    func flipCamera(){
+    func getCameraInfo(_ result: @escaping FlutterResult) -> Void {
+        if let sc: MTBBarcodeScanner = scanner {
+            result(sc.camera.rawValue)
+        } else {
+            let error = FlutterError(code: "cameraInformationError", message: "Could not get camera information", details: nil)
+            result(error)
+        }
+    }
+    
+    func flipCamera(_ result: @escaping FlutterResult){
         if let sc: MTBBarcodeScanner = scanner {
             if sc.hasOppositeCamera() {
                 sc.flipCamera()
             }
+            return result(sc.camera.rawValue)
         }
+        return result(FlutterError(code: "404", message: "No barcode scanner found", details: nil))
     }
     
-    func toggleFlash(){
+    func getFlashInfo(_ result: @escaping FlutterResult) -> Void {
+        if let sc: MTBBarcodeScanner = scanner {
+            result(sc.torchMode.rawValue != 0)
+        } else {
+            let error = FlutterError(code: "cameraInformationError", message: "Could not get flash information", details: nil)
+            result(error)
+        }
+    }
+    
+    func toggleFlash(_ result: @escaping FlutterResult){
         if let sc: MTBBarcodeScanner = scanner {
             if sc.hasTorch() {
                 sc.toggleTorch()
+                return result(sc.torchMode == MTBTorchMode(rawValue: 1))
             }
+            return result(FlutterError(code: "404", message: "This device doesn\'t support flash", details: nil))
         }
+        return result(FlutterError(code: "404", message: "No barcode scanner found", details: nil))
     }
     
-    func pauseCamera() {
+    func pauseCamera(_ result: @escaping FlutterResult) {
         if let sc: MTBBarcodeScanner = scanner {
             if sc.isScanning() {
                 sc.freezeCapture()
             }
+            return result(true)
         }
+        return result(FlutterError(code: "404", message: "No barcode scanner found", details: nil))
     }
     
-    func resumeCamera() {
+    func resumeCamera(_ result: @escaping FlutterResult) {
         if let sc: MTBBarcodeScanner = scanner {
             if !sc.isScanning() {
                 sc.unfreezeCapture()
             }
+            return result(true)
+        }
+        return result(FlutterError(code: "404", message: "No barcode scanner found", details: nil))
+    }
+    
+    func showNativeAlertDialog(_ result: @escaping FlutterResult) -> Void {
+        UIAlertView(title: "Scanning Unavailable", message: "This app does not have permission to access the camera", delegate: nil, cancelButtonTitle: nil, otherButtonTitles: "Ok").show()
+        return result(true)
+    }
+
+    func getSystemFeatures(_ result: @escaping FlutterResult) -> Void {
+        if let sc: MTBBarcodeScanner = scanner {
+            var hasBackCameraVar = false
+            var hasFrontCameraVar = false
+            let camera = sc.camera
+
+            if(camera == MTBCamera(rawValue: 0)){
+                hasBackCameraVar = true
+                if sc.hasOppositeCamera() {
+                    hasFrontCameraVar = true
+                }
+            }else{
+                hasFrontCameraVar = true
+                if sc.hasOppositeCamera() {
+                    hasBackCameraVar = true
+                }
+            }
+            return result([
+                "hasFrontCamera": hasFrontCameraVar,
+                "hasBackCamera": hasBackCameraVar,
+                "hasFlash": sc.hasTorch(),
+                "activeCamera": camera.rawValue
+            ])
+        }
+        return result(FlutterError(code: "404", message: nil, details: nil))
+    }
+
+    func setBarcodeFormats(_ arguments: Array<Int>, _ result: @escaping FlutterResult){
+        do{
+            allowedBarcodeTypes.removeAll()
+            try arguments.forEach { arg in
+                allowedBarcodeTypes.append(try QRCodeTypes[arg]!)
+            }
+            result(true)
+        }catch{
+            result(FlutterError(code: "404", message: nil, details: nil))
         }
     }
-}
+ }

lib/qr_code_scanner.dart

@@ -1,2 +1,5 @@
 export 'src/qr_code_scanner.dart';
 export 'src/qr_scanner_overlay_shape.dart';
+export 'src/types/barcode.dart';
+export 'src/types/camera.dart';
+export 'src/types/features.dart';

lib/src/qr_code_scanner.dart

@@ -3,105 +3,16 @@ import 'dart:async';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
-import 'package:qr_code_scanner/qr_code_scanner.dart';
 
-typedef QRViewCreatedCallback = void Function(QRViewController);
-
-enum CameraFacing {
-  /// Shows back facing camera.
-  back,
-
-  /// Shows front facing camera.
-  front
-}
-
-enum BarcodeFormat {
-  /// Aztec 2D barcode format.
-  aztec,
-
-  /// CODABAR 1D format.
-  codabar,
-
-  /// Code 39 1D format.
-  code39,
-
-  /// Code 93 1D format.
-  code93,
-
-  /// Code 128 1D format.
-  code128,
-
-  /// Data Matrix 2D barcode format.
-  dataMatrix,
-
-  /// EAN-8 1D format.
-  ean8,
-
-  /// EAN-13 1D format.
-  ean13,
-
-  /// ITF (Interleaved Two of Five) 1D format.
-  itf,
-
-  /// MaxiCode 2D barcode format.
-  maxicode,
-
-  /// PDF417 format.
-  pdf417,
-
-  /// QR Code 2D barcode format.
-  qrcode,
-
-  /// RSS 14
-  rss14,
-
-  /// RSS EXPANDED
-  rssExpanded,
-
-  /// UPC-A 1D format.
-  upcA,
-
-  /// UPC-E 1D format.
-  upcE,
-
-  /// UPC/EAN extension format. Not a stand-alone format.
-  upcEanExtension
-}
-
-const _formatNames = <String, BarcodeFormat>{
-  'AZTEC': BarcodeFormat.aztec,
-  'CODABAR': BarcodeFormat.codabar,
-  'CODE_39': BarcodeFormat.code39,
-  'CODE_93': BarcodeFormat.code93,
-  'CODE_128': BarcodeFormat.code128,
-  'DATA_MATRIX': BarcodeFormat.dataMatrix,
-  'EAN_8': BarcodeFormat.ean8,
-  'EAN_13': BarcodeFormat.ean13,
-  'ITF': BarcodeFormat.itf,
-  'MAXICODE': BarcodeFormat.maxicode,
-  'PDF_417': BarcodeFormat.pdf417,
-  'QR_CODE': BarcodeFormat.qrcode,
-  'RSS_14': BarcodeFormat.rss14,
-  'RSS_EXPANDED': BarcodeFormat.rssExpanded,
-  'UPC_A': BarcodeFormat.upcA,
-  'UPC_E': BarcodeFormat.upcE,
-  'UPC_EAN_EXTENSION': BarcodeFormat.upcEanExtension,
-};
-
-/// The [Barcode] object holds information about the barcode or qr code.
-///
-/// [code] is the content of the barcode.
-/// [format] displays which type the code is.
-/// Only for Android, [rawBytes] gives a list of bytes of the result.
-class Barcode {
-  Barcode(this.code, this.format, this.rawBytes);
-
-  final String code;
-  final BarcodeFormat format;
+import 'qr_scanner_overlay_shape.dart';
+import 'types/barcode.dart';
+import 'types/barcode_format.dart';
+import 'types/camera.dart';
+import 'types/camera_exception.dart';
+import 'types/features.dart';
 
-  /// Raw bytes are only supported by Android.
-  final List<int> rawBytes;
-}
+typedef QRViewCreatedCallback = void Function(QRViewController);
+typedef PermissionSetCallback = void Function(QRViewController, bool);
 
 /// The [QRView] is the view where the camera and the barcode scanner gets displayed.
 class QRView extends StatefulWidget {
@@ -111,6 +22,8 @@ class QRView extends StatefulWidget {
     this.overlay,
     this.overlayMargin = EdgeInsets.zero,
     this.cameraFacing = CameraFacing.back,
+    this.onPermissionSet,
+    this.showNativeAlertDialog = false,
   })  : assert(key != null),
         assert(onQRViewCreated != null),
         super(key: key);
@@ -119,6 +32,8 @@ class QRView extends StatefulWidget {
   final ShapeBorder overlay;
   final EdgeInsetsGeometry overlayMargin;
   final CameraFacing cameraFacing;
+  final PermissionSetCallback onPermissionSet;
+  final bool showNativeAlertDialog;
 
   @override
   State<StatefulWidget> createState() => _QRViewState();
@@ -201,7 +116,8 @@ class _QRViewState extends State<QRView> {
     _channel = MethodChannel('net.touchcapture.qr.flutterqr/qrview_$id');
 
     // Start scan after creation of the view
-    final controller = QRViewController._(_channel, widget.key, cutOutSize)
+    final controller = QRViewController._(_channel, widget.key, cutOutSize,
+        widget.onPermissionSet, widget.showNativeAlertDialog)
       .._startScan(widget.key, cutOutSize);
 
     // Initialize the controller for controlling the QRView
@@ -225,10 +141,70 @@ class _QrCameraSettings {
   }
 }
 
+const _formatNames = <String, BarcodeFormat>{
+  'AZTEC': BarcodeFormat.aztec,
+  'CODABAR': BarcodeFormat.codabar,
+  'CODE_39': BarcodeFormat.code39,
+  'CODE_93': BarcodeFormat.code93,
+  'CODE_128': BarcodeFormat.code128,
+  'DATA_MATRIX': BarcodeFormat.dataMatrix,
+  'EAN_8': BarcodeFormat.ean8,
+  'EAN_13': BarcodeFormat.ean13,
+  'ITF': BarcodeFormat.itf,
+  'MAXICODE': BarcodeFormat.maxicode,
+  'PDF_417': BarcodeFormat.pdf417,
+  'QR_CODE': BarcodeFormat.qrcode,
+  'RSS_14': BarcodeFormat.rss14,
+  'RSS_EXPANDED': BarcodeFormat.rssExpanded,
+  'UPC_A': BarcodeFormat.upcA,
+  'UPC_E': BarcodeFormat.upcE,
+  'UPC_EAN_EXTENSION': BarcodeFormat.upcEanExtension,
+};
+
 class QRViewController {
-  QRViewController._(MethodChannel channel, GlobalKey qrKey, double scanArea)
-      : _channel = channel {
-    _channel.setMethodCallHandler(_onMethodCall);
+  QRViewController._(
+    MethodChannel channel,
+    GlobalKey qrKey,
+    double scanArea,
+    PermissionSetCallback onPermissionSet,
+    bool showNativeAlertDialogOnError,
+  ) : _channel = channel {
+    _channel.setMethodCallHandler((call) async {
+      switch (call.method) {
+        case 'onRecognizeQR':
+          if (call.arguments != null) {
+            final args = call.arguments as Map;
+            final code = args['code'] as String;
+            final rawType = args['type'] as String;
+            // Raw bytes are only supported by Android.
+            final rawBytes = args['rawBytes'] as List<int>;
+            final format = _formatNames[rawType];
+            if (format != null) {
+              final barcode = Barcode(code, format, rawBytes);
+              _scanUpdateController.sink.add(barcode);
+            } else {
+              throw Exception('Unexpected barcode type $rawType');
+            }
+          }
+          break;
+        case 'onPermissionSet':
+          await getSystemFeatures(); // if we have no permission all features will not be avaible
+          if (call.arguments != null) {
+            if (call.arguments as bool) {
+              _hasPermissions = true;
+            } else {
+              _hasPermissions = false;
+              if (showNativeAlertDialogOnError) {
+                await showNativeAlertDialog();
+              }
+            }
+            if (onPermissionSet != null) {
+              onPermissionSet(this, call.arguments as bool);
+            }
+          }
+          break;
+      }
+    });
   }
 
   final MethodChannel _channel;
@@ -237,25 +213,11 @@ class QRViewController {
 
   Stream<Barcode> get scannedDataStream => _scanUpdateController.stream;
 
-  Future<void> _onMethodCall(MethodCall call) async {
-    switch (call.method) {
-      case 'onRecognizeQR':
-        if (call.arguments != null) {
-          final args = call.arguments as Map;
-          final code = args['code'] as String;
-          final rawType = args['type'] as String;
-          // Raw bytes are only supported by Android.
-          final rawBytes = args['rawBytes'] as List<int>;
-          final format = _formatNames[rawType];
-          if (format != null) {
-            final barcode = Barcode(code, format, rawBytes);
-            _scanUpdateController.sink.add(barcode);
-          } else {
-            throw Exception('Unexpected barcode type $rawType');
-          }
-        }
-    }
-  }
+  SystemFeatures _features;
+  bool _hasPermissions;
+
+  SystemFeatures get systemFeatures => _features;
+  bool get hasPermissions => _hasPermissions;
 
   /// Starts the barcode scanner
   Future<void> _startScan(
@@ -267,24 +229,86 @@ class QRViewController {
     return _channel.invokeMethod('startScan');
   }
 
+  Future<CameraFacing> getCameraInfo() async {
+    try {
+      return CameraFacing
+          .values[await _channel.invokeMethod('getCameraInfo') as int];
+    } on PlatformException catch (e) {
+      throw CameraException(e.code, e.message);
+    }
+  }
+
   /// Flips the camera between available modes
-  void flipCamera() {
-    _channel.invokeMethod('flipCamera');
+  Future<CameraFacing> flipCamera() async {
+    try {
+      return CameraFacing
+          .values[await _channel.invokeMethod('flipCamera') as int];
+    } on PlatformException catch (e) {
+      throw CameraException(e.code, e.message);
+    }
+  }
+
+  /// Get flashlight status
+  Future<bool> getFlashStatus() async {
+    try {
+      return await _channel.invokeMethod('getFlashInfo');
+    } on PlatformException catch (e) {
+      throw CameraException(e.code, e.message);
+    }
   }
 
   /// Toggles the flashlight between available modes
-  void toggleFlash() {
-    _channel.invokeMethod('toggleFlash');
+  Future<void> toggleFlash() async {
+    try {
+      await _channel.invokeMethod('toggleFlash') as bool;
+    } on PlatformException catch (e) {
+      throw CameraException(e.code, e.message);
+    }
   }
 
   /// Pauses barcode scanning
-  void pauseCamera() {
-    _channel.invokeMethod('pauseCamera');
+  Future<void> pauseCamera() async {
+    try {
+      await _channel.invokeMethod('pauseCamera');
+    } on PlatformException catch (e) {
+      throw CameraException(e.code, e.message);
+    }
   }
 
   /// Resumes barcode scanning
-  void resumeCamera() {
-    _channel.invokeMethod('resumeCamera');
+  Future<void> resumeCamera() async {
+    try {
+      await _channel.invokeMethod('resumeCamera');
+    } on PlatformException catch (e) {
+      throw CameraException(e.code, e.message);
+    }
+  }
+
+  Future<void> showNativeAlertDialog() async {
+    try {
+      await _channel.invokeMethod('showNativeAlertDialog');
+    } on PlatformException catch (e) {
+      throw CameraException(e.code, e.message);
+    }
+  }
+
+  Future<void> setAllowedBarcodeTypes(List<BarcodeFormat> list) async {
+    try {
+      await _channel.invokeMethod('setAllowedBarcodeFormats',
+          list?.map((e) => e.asInt())?.toList() ?? []);
+    } on PlatformException catch (e) {
+      throw CameraException(e.code, e.message);
+    }
+  }
+
+  Future<SystemFeatures> getSystemFeatures() async {
+    try {
+      var features =
+          await _channel.invokeMapMethod<String, dynamic>('getSystemFeatures');
+      return SystemFeatures.fromJson(features);
+    } on PlatformException catch (e) {
+      throw CameraException(e.code, e.message);
+    }
   }
 
   /// Disposes the barcode stream.

lib/src/types/barcode.dart

@@ -0,0 +1,16 @@
+import 'barcode_format.dart';
+
+/// The [Barcode] object holds information about the barcode or qr code.
+///
+/// [code] is the content of the barcode.
+/// [format] displays which type the code is.
+/// Only for Android, [rawBytes] gives a list of bytes of the result.
+class Barcode {
+  Barcode(this.code, this.format, this.rawBytes);
+
+  final String code;
+  final BarcodeFormat format;
+
+  /// Raw bytes are only supported by Android.
+  final List<int> rawBytes;
+}

lib/src/types/barcode_format.dart

@@ -0,0 +1,121 @@
+enum BarcodeFormat {
+  /// Aztec 2D barcode format.
+  aztec,
+
+  /// CODABAR 1D format.
+  codabar,
+
+  /// Code 39 1D format.
+  code39,
+
+  /// Code 93 1D format.
+  code93,
+
+  /// Code 128 1D format.
+  code128,
+
+  /// Data Matrix 2D barcode format.
+  dataMatrix,
+
+  /// EAN-8 1D format.
+  ean8,
+
+  /// EAN-13 1D format.
+  ean13,
+
+  /// ITF (Interleaved Two of Five) 1D format.
+  itf,
+
+  /// MaxiCode 2D barcode format.
+  maxicode,
+
+  /// PDF417 format.
+  pdf417,
+
+  /// QR Code 2D barcode format.
+  qrcode,
+
+  /// RSS 14
+  rss14,
+
+  /// RSS EXPANDED
+  rssExpanded,
+
+  /// UPC-A 1D format.
+  upcA,
+
+  /// UPC-E 1D format.
+  upcE,
+
+  /// UPC/EAN extension format. Not a stand-alone format.
+  upcEanExtension
+}
+
+extension BarcodeTypesExtension on BarcodeFormat {
+  int asInt() {
+    return index;
+  }
+
+  BarcodeFormat fromString(String format) {
+
+  }
+
+  String get formatName {
+    switch (this) {
+
+      case BarcodeFormat.aztec:
+        return 'AZTEC';
+        break;
+      case BarcodeFormat.codabar:
+        return 'CODABAR';
+        break;
+      case BarcodeFormat.code39:
+        return 'CODE_39';
+        break;
+      case BarcodeFormat.code93:
+        return 'CODE_93';
+        break;
+      case BarcodeFormat.code128:
+        return 'CODE_128';
+        break;
+      case BarcodeFormat.dataMatrix:
+        return 'DATA_MATRIX';
+        break;
+      case BarcodeFormat.ean8:
+        return 'EAN_8';
+        break;
+      case BarcodeFormat.ean13:
+        return 'EAN_13';
+        break;
+      case BarcodeFormat.itf:
+        return 'ITF';
+        break;
+      case BarcodeFormat.maxicode:
+        return 'MAXICODE';
+        break;
+      case BarcodeFormat.pdf417:
+        return 'PDF_417';
+        break;
+      case BarcodeFormat.qrcode:
+        return 'QR_CODE';
+        break;
+      case BarcodeFormat.rss14:
+        return 'RSS14';
+        break;
+      case BarcodeFormat.rssExpanded:
+        return 'RSS_EXPANDED';
+        break;
+      case BarcodeFormat.upcA:
+        return 'UPC_A';
+        break;
+      case BarcodeFormat.upcE:
+        return 'UPC_E';
+        break;
+      case BarcodeFormat.upcEanExtension:
+        return 'UPC_EAN_EXTENSION';
+        break;
+    }
+    return 'NOT_VALID';
+  }
+
+}

lib/src/types/camera.dart

@@ -0,0 +1,7 @@
+enum CameraFacing {
+  /// Shows back facing camera.
+  back,
+
+  /// Shows front facing camera.
+  front
+}

lib/src/types/camera_exception.dart

@@ -0,0 +1,14 @@
+/// This is thrown when the plugin reports an error.
+class CameraException implements Exception {
+  /// Creates a new camera exception with the given error code and description.
+  CameraException(this.code, this.description);
+
+  /// Error code.
+  String code;
+
+  /// Textual description of the error.
+  String description;
+
+  @override
+  String toString() => 'CameraException($code, $description)';
+}

lib/src/types/features.dart

@@ -0,0 +1,13 @@
+class SystemFeatures {
+  SystemFeatures(this.hasFlash, this.hasBackCamera, this.hasFrontCamera);
+
+  factory SystemFeatures.fromJson(Map<String, dynamic> features) =>
+      SystemFeatures(
+          features['hasFlash'] ?? false,
+          features['hasBackCamera'] ?? false,
+          features['hasFrontCamera'] ?? false);
+
+  final bool hasFlash;
+  final bool hasFrontCamera;
+  final bool hasBackCamera;
+}

pubspec.yaml

@@ -5,7 +5,7 @@ homepage: https://juliuscanute.com
 repository: https://github.com/juliuscanute/qr_code_scanner
 
 environment:
-  sdk: ">=2.3.0 <3.0.0"
+  sdk: ">=2.6.0 <3.0.0"
   flutter: ^1.10.0
 
 dependencies: