Merge branch 'master' into dependabot/gradle/android/org.jetbrains.kotlin-kotlin-stdlib-jdk7-1.7.22

Julian Steenbakker · GitHub
Commit 19c81dee050809e9d0250078ccd068c9beb8fa1d 19c81dee 2 parents 72c95631 3c14a1fa
Showing 17 changed files with 368 additions and 193 deletions
CHANGELOG.md
android/build.gradle
android/gradle/wrapper/gradle-wrapper.properties
android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScanner.kt
android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScannerPlugin.kt
example/lib/barcode_list_scanner_controller.dart
example/lib/barcode_scanner_controller.dart
example/lib/barcode_scanner_returning_image.dart
ios/Classes/SwiftMobileScannerPlugin.swift
lib/mobile_scanner.dart
lib/src/enums/mobile_scanner_error_code.dart
lib/src/enums/mobile_scanner_state.dart
lib/src/mobile_scanner.dart
lib/src/mobile_scanner_controller.dart
lib/src/mobile_scanner_exception.dart
macos/Classes/MobileScannerPlugin.swift
pubspec.yaml
--- a/CHANGELOG.md
View file @19c81de
+++ b/CHANGELOG.md
View file @19c81de
+## 3.0.0-beta.3
+Deprecated:
+* The `onStart` method has been renamed to `onScannerStarted`.
+* The `onPermissionSet` argument of the `MobileScannerController` is now deprecated.
+
+Breaking changes:
+* `MobileScannerException` now uses an `errorCode` instead of a `message`.
+* `MobileScannerException` now contains additional details from the original error.
+* Refactored `MobileScannerController.start()` to throw `MobileScannerException`s
+  with consistent error codes, rather than string messages.
+  To handle permission errors, consider catching the result of `MobileScannerController.start()`.
+* The `autoResume` attribute has been removed from the `MobileScanner` widget.
+  The controller already automatically resumes, so it had no effect.
+* Removed `MobileScannerCallback` and `MobileScannerArgumentsCallback` typedef.
+
+Improvements:
+* Toggling the device torch now does nothing if the device has no torch, rather than throwing an error.
+* Removed `called stop while already stopped` messages.
+
+Features:
+* Added a new `placeholderBuilder` function to the `MobileScanner` widget to customize the preview placeholder.
+* Added `autoStart` parameter to MobileScannerController(). If set to false, controller won't start automatically.
+* Added `hasTorch` function on MobileScannerController(). After starting the controller, you can check if the device has a torch.
+
+Fixes:
+* Fixes the missing gradle setup for the Android project, which prevented gradle sync from working.
+* Fixes `MobileScannerController.stop()` throwing when already stopped.
+* Fixes `MobileScannerController.toggleTorch()` throwing if the device has no torch.
+  Now it does nothing if the torch is not available.
+* Fixes a memory leak where the `MobileScanner` would keep listening to the barcode events.
+* Fixes the `MobileScanner` preview depending on all attributes of `MediaQueryData`.
+  Now it only depends on its layout constraints.
+* Fixed a potential crash when the scanner is restarted due to the app being resumed.
+  
 ## 3.0.0-beta.2
 Breaking changes:
 * The arguments parameter of onDetect is removed. The data is now returned by the onStart callback
--- a/android/build.gradle
View file @19c81de
+++ b/android/build.gradle
View file @19c81de
@@ -10,6 +10,7 @@ buildscript {
     dependencies {
         classpath 'com.android.tools.build:gradle:7.3.1'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
--- a/android/gradle/wrapper/gradle-wrapper.properties 0 → 100644
View file @19c81de
+++ b/android/gradle/wrapper/gradle-wrapper.properties 0 → 100644
View file @19c81de
+#Fri Jun 23 08:50:38 CEST 2017
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.4-all.zip
--- a/android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScanner.kt
View file @19c81de
+++ b/android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScanner.kt
View file @19c81de
@@ -17,10 +17,9 @@ import com.google.mlkit.vision.barcode.BarcodeScanning
 import com.google.mlkit.vision.common.InputImage
 import dev.steenbakker.mobile_scanner.objects.DetectionSpeed
 import dev.steenbakker.mobile_scanner.objects.MobileScannerStartParameters
+import io.flutter.plugin.common.MethodChannel
 import io.flutter.plugin.common.PluginRegistry
 import io.flutter.view.TextureRegistry
-
-typealias PermissionCallback = (permissionGranted: Boolean) -> Unit
 typealias MobileScannerCallback = (barcodes: List<Map<String, Any?>>, image: ByteArray?) -> Unit
 typealias AnalyzerCallback = (barcodes: List<Map<String, Any?>>?) -> Unit
 typealias MobileScannerErrorCallback = (error: String) -> Unit
@@ -49,10 +48,9 @@ class MobileScanner(
         private const val REQUEST_CODE = 0x0786
     }
-    private var listener: PluginRegistry.RequestPermissionsResultListener? = null
-
     private var cameraProvider: ProcessCameraProvider? = null
     private var camera: Camera? = null
+    private var pendingPermissionResult: MethodChannel.Result? = null
     private var preview: Preview? = null
     private var textureEntry: TextureRegistry.SurfaceTextureEntry? = null
@@ -86,17 +84,12 @@ class MobileScanner(
     /**
      * Request camera permissions.
      */
-    fun requestPermission(permissionCallback: PermissionCallback) {
-        listener
-            ?: PluginRegistry.RequestPermissionsResultListener { requestCode, _, grantResults ->
-                if (requestCode != REQUEST_CODE) {
-                    false
-                } else {
-                    val authorized = grantResults[0] == PackageManager.PERMISSION_GRANTED
-                    permissionCallback(authorized)
-                    true
-                }
+    fun requestPermission(result: MethodChannel.Result) {
+        if(pendingPermissionResult != null) {
+            return
         }
+
+        pendingPermissionResult = result
         val permissions = arrayOf(Manifest.permission.CAMERA)
         ActivityCompat.requestPermissions(activity, permissions, REQUEST_CODE)
     }
@@ -109,7 +102,14 @@ class MobileScanner(
         permissions: Array<out String>,
         grantResults: IntArray
     ): Boolean {
-        return listener?.onRequestPermissionsResult(requestCode, permissions, grantResults) ?: false
+        if (requestCode != REQUEST_CODE) {
+            return false
+        }
+
+        pendingPermissionResult?.success(grantResults[0] == PackageManager.PERMISSION_GRANTED)
+        pendingPermissionResult = null
+
+        return true
     }
     /**
--- a/android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScannerPlugin.kt
View file @19c81de
+++ b/android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScannerPlugin.kt
View file @19c81de
@@ -23,14 +23,8 @@ class MobileScannerPlugin : FlutterPlugin, ActivityAware, MethodChannel.MethodCa
     private lateinit var barcodeHandler: BarcodeHandler
-    private var permissionResult: MethodChannel.Result? = null
     private var analyzerResult: MethodChannel.Result? = null
-    private val permissionCallback: PermissionCallback = {hasPermission: Boolean ->
-        permissionResult?.success(hasPermission)
-        permissionResult = null
-    }
-
     private val callback: MobileScannerCallback = { barcodes: List<Map<String, Any?>>, image: ByteArray? ->
         if (image != null) {
             barcodeHandler.publishEvent(mapOf(
@@ -78,7 +72,7 @@ class MobileScannerPlugin : FlutterPlugin, ActivityAware, MethodChannel.MethodCa
         }
         when (call.method) {
             "state" -> result.success(handler!!.hasCameraPermission())
-            "request" -> requestPermission(result)
+            "request" -> handler!!.requestPermission(result)
             "start" -> start(call, result)
             "torch" -> toggleTorch(call, result)
             "stop" -> stop(result)
@@ -124,11 +118,6 @@ class MobileScannerPlugin : FlutterPlugin, ActivityAware, MethodChannel.MethodCa
         onDetachedFromActivity()
     }
-    private fun requestPermission(result: MethodChannel.Result) {
-        permissionResult = result
-        handler!!.requestPermission(permissionCallback)
-    }
-
     @ExperimentalGetImage
     private fun start(call: MethodCall, result: MethodChannel.Result) {
         val torch: Boolean = call.argument<Boolean>("torch") ?: false
@@ -208,7 +197,7 @@ class MobileScannerPlugin : FlutterPlugin, ActivityAware, MethodChannel.MethodCa
             handler!!.stop()
             result.success(null)
         } catch (e: AlreadyStopped) {
-            result.error("MobileScanner", "Called stop() while already stopped!", null)
+            result.success(null)
         }
     }
--- a/example/lib/barcode_list_scanner_controller.dart
View file @19c81de
+++ b/example/lib/barcode_list_scanner_controller.dart
View file @19c81de
@@ -15,13 +15,10 @@ class _BarcodeListScannerWithControllerState
     with SingleTickerProviderStateMixin {
   BarcodeCapture? barcodeCapture;
-  MobileScannerController controller = MobileScannerController(
+  final MobileScannerController controller = MobileScannerController(
     torchEnabled: true,
     // formats: [BarcodeFormat.qrCode]
     // facing: CameraFacing.front,
-    onPermissionSet: (hasPermission) {
-      // Do something with permission callback
-    },
     // detectionSpeed: DetectionSpeed.normal
     // detectionTimeoutMs: 1000,
     // returnImage: false,
@@ -29,6 +26,31 @@ class _BarcodeListScannerWithControllerState
   bool isStarted = true;
+  void _startOrStop() {
+    if (isStarted) {
+      controller.stop();
+    } else {
+      controller.start().catchError((error) {
+        final exception = error as MobileScannerException;
+
+        switch (exception.errorCode) {
+          case MobileScannerErrorCode.controllerUninitialized:
+            break; // This error code is not used by `start()`.
+          case MobileScannerErrorCode.genericError:
+            debugPrint('Scanner failed to start');
+            break;
+          case MobileScannerErrorCode.permissionDenied:
+            debugPrint('Camera permission denied');
+            break;
+        }
+      });
+    }
+
+    setState(() {
+      isStarted = !isStarted;
+    });
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
@@ -40,17 +62,13 @@ class _BarcodeListScannerWithControllerState
               MobileScanner(
                 controller: controller,
                 fit: BoxFit.contain,
-                // controller: MobileScannerController(
-                //   torchEnabled: true,
-                //   facing: CameraFacing.front,
-                // ),
                 onDetect: (barcodeCapture) {
                   setState(() {
                     this.barcodeCapture = barcodeCapture;
                   });
                 },
-                onStart: (arguments) {
-                  // Do something with start arguments
+                onScannerStarted: (arguments) {
+                  // Do something with arguments.
                 },
               ),
               Align(
@@ -96,10 +114,7 @@ class _BarcodeListScannerWithControllerState
                             ? const Icon(Icons.stop)
                             : const Icon(Icons.play_arrow),
                         iconSize: 32.0,
-                        onPressed: () => setState(() {
-                          isStarted ? controller.stop() : controller.start();
-                          isStarted = !isStarted;
-                        }),
+                        onPressed: _startOrStop,
                       ),
                       Center(
                         child: SizedBox(
@@ -177,4 +192,10 @@ class _BarcodeListScannerWithControllerState
       ),
     );
   }
+
+  @override
+  void dispose() {
+    controller.dispose();
+    super.dispose();
+  }
 }
--- a/example/lib/barcode_scanner_controller.dart
View file @19c81de
+++ b/example/lib/barcode_scanner_controller.dart
View file @19c81de
@@ -15,13 +15,10 @@ class _BarcodeScannerWithControllerState
     with SingleTickerProviderStateMixin {
   BarcodeCapture? barcode;
-  MobileScannerController controller = MobileScannerController(
+  final MobileScannerController controller = MobileScannerController(
     torchEnabled: true,
     // formats: [BarcodeFormat.qrCode]
     // facing: CameraFacing.front,
-    onPermissionSet: (hasPermission) {
-      // Do something with permission callback
-    },
     // detectionSpeed: DetectionSpeed.normal
     // detectionTimeoutMs: 1000,
     // returnImage: false,
@@ -29,6 +26,31 @@ class _BarcodeScannerWithControllerState
   bool isStarted = true;
+  void _startOrStop() {
+    if (isStarted) {
+      controller.stop();
+    } else {
+      controller.start().catchError((error) {
+        final exception = error as MobileScannerException;
+
+        switch (exception.errorCode) {
+          case MobileScannerErrorCode.controllerUninitialized:
+            break; // This error code is not used by `start()`.
+          case MobileScannerErrorCode.genericError:
+            debugPrint('Scanner failed to start');
+            break;
+          case MobileScannerErrorCode.permissionDenied:
+            debugPrint('Camera permission denied');
+            break;
+        }
+      });
+    }
+
+    setState(() {
+      isStarted = !isStarted;
+    });
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
@@ -40,10 +62,6 @@ class _BarcodeScannerWithControllerState
               MobileScanner(
                 controller: controller,
                 fit: BoxFit.contain,
-                // controller: MobileScannerController(
-                //   torchEnabled: true,
-                //   facing: CameraFacing.front,
-                // ),
                 onDetect: (barcode) {
                   setState(() {
                     this.barcode = barcode;
@@ -93,10 +111,7 @@ class _BarcodeScannerWithControllerState
                             ? const Icon(Icons.stop)
                             : const Icon(Icons.play_arrow),
                         iconSize: 32.0,
-                        onPressed: () => setState(() {
-                          isStarted ? controller.stop() : controller.start();
-                          isStarted = !isStarted;
-                        }),
+                        onPressed: _startOrStop,
                       ),
                       Center(
                         child: SizedBox(
@@ -175,4 +190,10 @@ class _BarcodeScannerWithControllerState
       ),
     );
   }
+
+  @override
+  void dispose() {
+    controller.dispose();
+    super.dispose();
+  }
 }
--- a/example/lib/barcode_scanner_returning_image.dart
View file @19c81de
+++ b/example/lib/barcode_scanner_returning_image.dart
View file @19c81de
@@ -17,13 +17,10 @@ class _BarcodeScannerReturningImageState
   BarcodeCapture? barcode;
   MobileScannerArguments? arguments;
-  MobileScannerController controller = MobileScannerController(
+  final MobileScannerController controller = MobileScannerController(
     torchEnabled: true,
     // formats: [BarcodeFormat.qrCode]
     // facing: CameraFacing.front,
-    onPermissionSet: (hasPermission) {
-      // Do something with permission callback
-    },
     // detectionSpeed: DetectionSpeed.normal
     // detectionTimeoutMs: 1000,
     returnImage: true,
@@ -31,6 +28,31 @@ class _BarcodeScannerReturningImageState
   bool isStarted = true;
+  void _startOrStop() {
+    if (isStarted) {
+      controller.stop();
+    } else {
+      controller.start().catchError((error) {
+        final exception = error as MobileScannerException;
+
+        switch (exception.errorCode) {
+          case MobileScannerErrorCode.controllerUninitialized:
+            break; // This error code is not used by `start()`.
+          case MobileScannerErrorCode.genericError:
+            debugPrint('Scanner failed to start');
+            break;
+          case MobileScannerErrorCode.permissionDenied:
+            debugPrint('Camera permission denied');
+            break;
+        }
+      });
+    }
+
+    setState(() {
+      isStarted = !isStarted;
+    });
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
@@ -62,10 +84,6 @@ class _BarcodeScannerReturningImageState
                     MobileScanner(
                       controller: controller,
                       fit: BoxFit.contain,
-                      // controller: MobileScannerController(
-                      //   torchEnabled: true,
-                      //   facing: CameraFacing.front,
-                      // ),
                       onDetect: (barcode) {
                         setState(() {
                           this.barcode = barcode;
@@ -115,12 +133,7 @@ class _BarcodeScannerReturningImageState
                                   ? const Icon(Icons.stop)
                                   : const Icon(Icons.play_arrow),
                               iconSize: 32.0,
-                              onPressed: () => setState(() {
-                                isStarted
-                                    ? controller.stop()
-                                    : controller.start();
-                                isStarted = !isStarted;
-                              }),
+                              onPressed: _startOrStop,
                             ),
                             Center(
                               child: SizedBox(
@@ -171,4 +184,10 @@ class _BarcodeScannerReturningImageState
       ),
     );
   }
+
+  @override
+  void dispose() {
+    controller.dispose();
+    super.dispose();
+  }
 }
--- a/ios/Classes/SwiftMobileScannerPlugin.swift
View file @19c81de
+++ b/ios/Classes/SwiftMobileScannerPlugin.swift
View file @19c81de
@@ -107,11 +107,7 @@ public class SwiftMobileScannerPlugin: NSObject, FlutterPlugin {
     private func stop(_ result: @escaping FlutterResult) {
         do {
             try mobileScanner.stop()
-        } catch {
-            result(FlutterError(code: "MobileScanner",
-                                message: "Called stop() while already stopped!",
-                                details: nil))
-        }
+        } catch {}
         result(nil)
     }
--- a/lib/mobile_scanner.dart
View file @19c81de
+++ b/lib/mobile_scanner.dart
View file @19c81de
@@ -2,11 +2,13 @@ library mobile_scanner;
 export 'src/enums/camera_facing.dart';
 export 'src/enums/detection_speed.dart';
+export 'src/enums/mobile_scanner_error_code.dart';
 export 'src/enums/mobile_scanner_state.dart';
 export 'src/enums/ratio.dart';
 export 'src/enums/torch_state.dart';
 export 'src/mobile_scanner.dart';
 export 'src/mobile_scanner_controller.dart';
+export 'src/mobile_scanner_exception.dart';
 export 'src/objects/barcode.dart';
 export 'src/objects/barcode_capture.dart';
 export 'src/objects/mobile_scanner_arguments.dart';
--- a/lib/src/enums/mobile_scanner_error_code.dart 0 → 100644
View file @19c81de
+++ b/lib/src/enums/mobile_scanner_error_code.dart 0 → 100644
View file @19c81de
+/// This enum defines the different error codes for the mobile scanner.
+enum MobileScannerErrorCode {
+  /// The controller was used
+  /// while it was not yet initialized using [MobileScannerController.start].
+  controllerUninitialized,
+
+  /// A generic error occurred.
+  ///
+  /// This error code is used for all errors that do not have a specific error code.
+  genericError,
+
+  /// The permission to use the camera was denied.
+  permissionDenied,
+}
--- a/lib/src/enums/mobile_scanner_state.dart
View file @19c81de
+++ b/lib/src/enums/mobile_scanner_state.dart
View file @19c81de
 /// The authorization state of the scanner.
 enum MobileScannerState {
-  /// The scanner has yet to request weather it is [authorized] or [denied]
+  /// The scanner has not yet requested the required permissions.
   undetermined,
   /// The scanner has the required permissions.
--- a/lib/src/mobile_scanner.dart
View file @19c81de
+++ b/lib/src/mobile_scanner.dart
View file @19c81de
+import 'dart:async';
+
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:mobile_scanner/src/mobile_scanner_controller.dart';
 import 'package:mobile_scanner/src/objects/barcode_capture.dart';
 import 'package:mobile_scanner/src/objects/mobile_scanner_arguments.dart';
-typedef MobileScannerCallback = void Function(BarcodeCapture barcodes);
-typedef MobileScannerArgumentsCallback = void Function(
-  MobileScannerArguments? arguments,
-);
-
-/// A widget showing a live camera preview.
+/// The [MobileScanner] widget displays a live camera preview.
 class MobileScanner extends StatefulWidget {
-  /// The controller of the camera.
+  /// The controller that manages the barcode scanner.
+  ///
+  /// If this is null, the scanner will manage its own controller.
   final MobileScannerController? controller;
-  /// Calls the provided [onPermissionSet] callback when the permission is set.
-  // @Deprecated('Use the [onPermissionSet] paremeter in the [MobileScannerController] instead.')
-  // ignore: deprecated_consistency
-  final Function(bool permissionGranted)? onPermissionSet;
-
-  /// Function that gets called when a Barcode is detected.
+  /// The [BoxFit] for the camera preview.
   ///
-  /// [barcode] The barcode object with all information about the scanned code.
-  /// [startInternalArguments] Information about the state of the MobileScanner widget
-  final MobileScannerCallback onDetect;
+  /// Defaults to [BoxFit.cover].
+  final BoxFit fit;
-  /// Function that gets called when the scanner is started.
-  ///
-  /// [arguments] The start arguments of the scanner. This contains the size of
-  /// the scanner which can be used to draw a box over the scanner.
-  final MobileScannerArgumentsCallback? onStart;
+  /// The function that signals when new codes were detected by the [controller].
+  final void Function(BarcodeCapture barcodes) onDetect;
-  /// Handles how the widget should fit the screen.
-  final BoxFit fit;
+  /// The function that signals when the barcode scanner is started.
+  @Deprecated('Use onScannerStarted() instead.')
+  final void Function(MobileScannerArguments? arguments)? onStart;
+
+  /// The function that signals when the barcode scanner is started.
+  final void Function(MobileScannerArguments? arguments)? onScannerStarted;
-  /// Whether to automatically resume the camera when the application is resumed
-  final bool autoResume;
+  /// The function that builds a placeholder widget when the scanner
+  /// is not yet displaying its camera preview.
+  ///
+  /// If this is null, a black [ColoredBox] is used as placeholder.
+  final Widget Function(BuildContext, Widget?)? placeholderBuilder;
-  /// Create a [MobileScanner] with a [controller], the [controller] must has been initialized.
+  /// Create a new [MobileScanner] using the provided [controller]
+  /// and [onBarcodeDetected] callback.
   const MobileScanner({
-    super.key,
-    required this.onDetect,
-    this.onStart,
     this.controller,
-    this.autoResume = true,
     this.fit = BoxFit.cover,
-    @Deprecated('Use the [onPermissionSet] paremeter in the [MobileScannerController] instead.')
-        this.onPermissionSet,
+    required this.onDetect,
+    @Deprecated('Use onScannerStarted() instead.') this.onStart,
+    this.onScannerStarted,
+    this.placeholderBuilder,
+    super.key,
   });
   @override
@@ -55,65 +52,86 @@ class MobileScanner extends StatefulWidget {
 class _MobileScannerState extends State<MobileScanner>
     with WidgetsBindingObserver {
-  late MobileScannerController controller;
+  /// The subscription that listens to barcode detection.
+  StreamSubscription<BarcodeCapture>? _barcodesSubscription;
+
+  /// The internally managed controller.
+  late MobileScannerController _controller;
+
+  /// Whether the controller should resume
+  /// when the application comes back to the foreground.
+  bool _resumeFromBackground = false;
+
+  /// Start the given [scanner].
+  void _startScanner(MobileScannerController scanner) {
+    if (!_controller.autoStart) {
+      debugPrint(
+        'mobile_scanner: not starting automatically because autoStart is set to false in the controller.',
+      );
+      return;
+    }
+    scanner.start().then((arguments) {
+      // ignore: deprecated_member_use_from_same_package
+      widget.onStart?.call(arguments);
+      widget.onScannerStarted?.call(arguments);
+    });
+  }
   @override
   void initState() {
     super.initState();
     WidgetsBinding.instance.addObserver(this);
-    controller = widget.controller ??
-        MobileScannerController(onPermissionSet: widget.onPermissionSet);
-    if (!controller.isStarting) {
-      _startScanner();
-    }
-  }
+    _controller = widget.controller ?? MobileScannerController();
-  Future<void> _startScanner() async {
-    final arguments = await controller.start();
-    widget.onStart?.call(arguments);
-  }
+    _barcodesSubscription = _controller.barcodes.listen(
+      widget.onDetect,
+    );
-  bool resumeFromBackground = false;
+    if (!_controller.isStarting) {
+      _startScanner(_controller);
+    }
+  }
   @override
   void didChangeAppLifecycleState(AppLifecycleState state) {
-    // App state changed before it is initialized.
-    if (controller.isStarting) {
+    // App state changed before the controller was initialized.
+    if (_controller.isStarting) {
       return;
     }
     switch (state) {
       case AppLifecycleState.resumed:
-        resumeFromBackground = false;
-        _startScanner();
+        _resumeFromBackground = false;
+        _startScanner(_controller);
         break;
       case AppLifecycleState.paused:
-        resumeFromBackground = true;
+        _resumeFromBackground = true;
         break;
       case AppLifecycleState.inactive:
-        if (!resumeFromBackground) controller.stop();
+        if (!_resumeFromBackground) {
+          _controller.stop();
+        }
         break;
-      default:
+      case AppLifecycleState.detached:
         break;
     }
   }
   @override
   Widget build(BuildContext context) {
-    return ValueListenableBuilder(
-      valueListenable: controller.startArguments,
+    return ValueListenableBuilder<MobileScannerArguments?>(
+      valueListenable: _controller.startArguments,
       builder: (context, value, child) {
-        value = value as MobileScannerArguments?;
         if (value == null) {
-          return const ColoredBox(color: Colors.black);
-        } else {
-          controller.barcodes.listen((barcode) {
-            widget.onDetect(barcode);
-          });
+          return widget.placeholderBuilder?.call(context, child) ??
+              const ColoredBox(color: Colors.black);
+        }
+
         return ClipRect(
-            child: SizedBox(
-              width: MediaQuery.of(context).size.width,
-              height: MediaQuery.of(context).size.height,
+          child: LayoutBuilder(
+            builder: (_, constraints) {
+              return SizedBox.fromSize(
+                size: constraints.biggest,
                 child: FittedBox(
                   fit: widget.fit,
                   child: SizedBox(
@@ -124,35 +142,19 @@ class _MobileScannerState extends State<MobileScanner>
                         : Texture(textureId: value.textureId!),
                   ),
                 ),
+              );
+            },
           ),
         );
-        }
       },
     );
   }
   @override
-  void didUpdateWidget(covariant MobileScanner oldWidget) {
-    super.didUpdateWidget(oldWidget);
-    if (oldWidget.controller == null) {
-      if (widget.controller != null) {
-        controller.dispose();
-        controller = widget.controller!;
-      }
-    } else {
-      if (widget.controller == null) {
-        controller =
-            MobileScannerController(onPermissionSet: widget.onPermissionSet);
-      } else if (oldWidget.controller != widget.controller) {
-        controller = widget.controller!;
-      }
-    }
-  }
-
-  @override
   void dispose() {
-    controller.dispose();
     WidgetsBinding.instance.removeObserver(this);
+    _barcodesSubscription?.cancel();
+    _controller.dispose();
     super.dispose();
   }
 }
--- a/lib/src/mobile_scanner_controller.dart
View file @19c81de
+++ b/lib/src/mobile_scanner_controller.dart
View file @19c81de
@@ -6,7 +6,6 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 import 'package:mobile_scanner/mobile_scanner.dart';
 import 'package:mobile_scanner/src/barcode_utility.dart';
-import 'package:mobile_scanner/src/mobile_scanner_exception.dart';
 /// The [MobileScannerController] holds all the logic of this plugin,
 /// where as the [MobileScanner] class is the frontend of this plugin.
@@ -18,7 +17,9 @@ class MobileScannerController {
     this.torchEnabled = false,
     this.formats,
     this.returnImage = false,
+    @Deprecated('Instead, use the result of calling `start()` to determine if permissions were granted.')
         this.onPermissionSet,
+    this.autoStart = true,
   }) {
     // In case a new instance is created before calling dispose()
     if (controllerHashcode != null) {
@@ -64,6 +65,9 @@ class MobileScannerController {
   /// [DetectionSpeed.normal] (which is the default value).
   final int detectionTimeoutMs;
+  /// Automatically start the mobileScanner on initialization.
+  final bool autoStart;
+
   /// Sets the barcode stream
   final StreamController<BarcodeCapture> _barcodesController =
       StreamController.broadcast();
@@ -74,6 +78,9 @@ class MobileScannerController {
   static const EventChannel _eventChannel =
       EventChannel('dev.steenbakker.mobile_scanner/scanner/event');
+  @Deprecated(
+    'Instead, use the result of calling `start()` to determine if permissions were granted.',
+  )
   Function(bool permissionGranted)? onPermissionSet;
   /// Listen to events from the platform specific code
@@ -94,6 +101,19 @@ class MobileScannerController {
   bool? _hasTorch;
+  /// Returns whether the device has a torch.
+  ///
+  /// Throws an error if the controller is not initialized.
+  bool get hasTorch {
+    if (_hasTorch == null) {
+      throw const MobileScannerException(
+        errorCode: MobileScannerErrorCode.controllerUninitialized,
+      );
+    }
+
+    return _hasTorch!;
+  }
+
   /// Set the starting arguments for the camera
   Map<String, dynamic> _argumentsToMap({CameraFacing? cameraFacingOverride}) {
     final Map<String, dynamic> arguments = {};
@@ -115,8 +135,14 @@ class MobileScannerController {
     return arguments;
   }
-  /// Start barcode scanning. This will first check if the required permissions
-  /// are set.
+  /// Start scanning for barcodes.
+  /// Upon calling this method, the necessary camera permission will be requested.
+  ///
+  /// Returns an instance of [MobileScannerArguments]
+  /// when the scanner was successfully started.
+  /// Returns null if the scanner is currently starting.
+  ///
+  /// Throws a [MobileScannerException] if starting the scanner failed.
   Future<MobileScannerArguments?> start({
     CameraFacing? cameraFacingOverride,
   }) async {
@@ -124,6 +150,7 @@ class MobileScannerController {
       debugPrint("Called start() while starting.");
       return null;
     }
+
     isStarting = true;
     // Check authorization status
@@ -136,16 +163,17 @@ class MobileScannerController {
               await _methodChannel.invokeMethod('request') as bool? ?? false;
           if (!result) {
             isStarting = false;
-            onPermissionSet?.call(result);
-            throw MobileScannerException('User declined camera permission.');
+            throw const MobileScannerException(
+              errorCode: MobileScannerErrorCode.permissionDenied,
+            );
           }
           break;
         case MobileScannerState.denied:
           isStarting = false;
-          onPermissionSet?.call(false);
-          throw MobileScannerException('User declined camera permission.');
+          throw const MobileScannerException(
+            errorCode: MobileScannerErrorCode.permissionDenied,
+          );
         case MobileScannerState.authorized:
-          onPermissionSet?.call(true);
           break;
       }
     }
@@ -158,18 +186,27 @@ class MobileScannerController {
         _argumentsToMap(cameraFacingOverride: cameraFacingOverride),
       );
     } on PlatformException catch (error) {
-      debugPrint('${error.code}: ${error.message}');
+      MobileScannerErrorCode errorCode = MobileScannerErrorCode.genericError;
+
       if (error.code == "MobileScannerWeb") {
-        onPermissionSet?.call(false);
+        errorCode = MobileScannerErrorCode.permissionDenied;
       }
       isStarting = false;
-      return null;
+
+      throw MobileScannerException(
+        errorCode: errorCode,
+        errorDetails: MobileScannerErrorDetails(
+          code: error.code,
+          details: error.details as Object?,
+          message: error.message,
+        ),
+      );
     }
     if (startResult == null) {
       isStarting = false;
-      throw MobileScannerException(
-        'Failed to start mobileScanner, no response from platform side',
+      throw const MobileScannerException(
+        errorCode: MobileScannerErrorCode.genericError,
       );
     }
@@ -178,13 +215,6 @@ class MobileScannerController {
       torchState.value = TorchState.on;
     }
-    if (kIsWeb) {
-      // If we reach this line, it means camera permission has been granted
-      onPermissionSet?.call(
-        true,
-      );
-    }
-
     isStarting = false;
     return startArguments.value = MobileScannerArguments(
       size: kIsWeb
@@ -210,14 +240,18 @@ class MobileScannerController {
   /// Switches the torch on or off.
   ///
-  /// Only works if torch is available.
+  /// Does nothing if the device has no torch.
+  ///
+  /// Throws if the controller was not initialized.
   Future<void> toggleTorch() async {
-    if (_hasTorch == null) {
-      throw MobileScannerException(
-        'Cannot toggle torch if start() has never been called',
+    final hasTorch = _hasTorch;
+
+    if (hasTorch == null) {
+      throw const MobileScannerException(
+        errorCode: MobileScannerErrorCode.controllerUninitialized,
       );
-    } else if (!_hasTorch!) {
-      throw MobileScannerException('Device has no torch');
+    } else if (!hasTorch) {
+      return;
     }
     torchState.value =
@@ -258,7 +292,6 @@ class MobileScannerController {
     _barcodesController.close();
     if (hashCode == controllerHashcode) {
       controllerHashcode = null;
-      onPermissionSet = null;
     }
   }
@@ -307,7 +340,10 @@ class MobileScannerController {
         );
         break;
       case 'error':
-        throw MobileScannerException(data as String);
+        throw MobileScannerException(
+          errorCode: MobileScannerErrorCode.genericError,
+          errorDetails: MobileScannerErrorDetails(message: data as String?),
+        );
       default:
         throw UnimplementedError(name as String?);
     }
--- a/lib/src/mobile_scanner_exception.dart
View file @19c81de
+++ b/lib/src/mobile_scanner_exception.dart
View file @19c81de
+import 'package:mobile_scanner/src/enums/mobile_scanner_error_code.dart';
+
+/// This class represents an exception thrown by the mobile scanner.
 class MobileScannerException implements Exception {
-  String message;
-  MobileScannerException(this.message);
+  const MobileScannerException({
+    required this.errorCode,
+    this.errorDetails,
+  });
+
+  /// The error code of the exception.
+  final MobileScannerErrorCode errorCode;
+
+  /// The additional error details that came with the [errorCode].
+  final MobileScannerErrorDetails? errorDetails;
+
+  @override
+  String toString() {
+    if (errorDetails != null && errorDetails?.message != null) {
+      return "MobileScannerException: code ${errorCode.name}, message: ${errorDetails?.message}";
+    }
+    return "MobileScannerException: ${errorCode.name}";
+  }
+}
+
+/// The raw error details for a [MobileScannerException].
+class MobileScannerErrorDetails {
+  const MobileScannerErrorDetails({
+    this.code,
+    this.details,
+    this.message,
+  });
+
+  /// The error code from the [PlatformException].
+  final String? code;
+
+  /// The details from the [PlatformException].
+  final Object? details;
+
+  /// The error message from the [PlatformException].
+  final String? message;
 }
--- a/macos/Classes/MobileScannerPlugin.swift
View file @19c81de
+++ b/macos/Classes/MobileScannerPlugin.swift
View file @19c81de
@@ -238,9 +238,7 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
     func toggleTorch(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
         if (device == nil) {
-            result(FlutterError(code: "MobileScanner",
-                                    message: "Called toggleTorch() while stopped!",
-                                    details: nil))
+            result(nil)
             return
         }
         do {
@@ -260,9 +258,8 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
     func stop(_ result: FlutterResult) {
         if (device == nil) {
-            result(FlutterError(code: "MobileScanner",
-                                    message: "Called stop() while already stopped!",
-                                    details: nil))
+            result(nil)
+
             return
         }
         captureSession.stopRunning()
--- a/pubspec.yaml
View file @19c81de
+++ b/pubspec.yaml
View file @19c81de
 name: mobile_scanner
 description: A universal barcode and QR code scanner for Flutter based on MLKit. Uses CameraX on Android, AVFoundation on iOS and Apple Vision & AVFoundation on macOS.
-version: 3.0.0-beta.2
+version: 3.0.0-beta.3
 repository: https://github.com/juliansteenbakker/mobile_scanner
 environment: