Merge pull request #826 from navaronbracke/fix_platform_messages_threading

fix: Fix platform messages threading

@@ -15,6 +15,7 @@ Bugs fixed:
 * Fixed the default values for the `format` and `type` arguments of the Barcode constructor.
   These now use `BarcodeFormat.unknown` and `BarcodeType.unknown`, rather than `BarcodeFormat.ean13` and `BarcodeType.text`.
   (thanks @navaronbracke !)
+* Fixed messages not being sent on the main thread for Android, iOS and MacOS. (thanks @navaronbracke !)
 
 ## 3.5.0
 New Features:

@@ -2,6 +2,8 @@ package dev.steenbakker.mobile_scanner
 
 import android.app.Activity
 import android.net.Uri
+import android.os.Handler
+import android.os.Looper
 import android.util.Size
 import androidx.camera.core.CameraSelector
 import androidx.camera.core.ExperimentalGetImage
@@ -30,12 +32,13 @@ class MobileScannerHandler(
                 "name" to "barcode",
                 "data" to barcodes
             ))
-            analyzerResult?.success(true)
-        } else {
-            analyzerResult?.success(false)
         }
+
+        Handler(Looper.getMainLooper()).post {
+            analyzerResult?.success(barcodes != null)
             analyzerResult = null
         }
+    }
 
     private var analyzerResult: MethodChannel.Result? = null
 
@@ -92,7 +95,6 @@ class MobileScannerHandler(
         if(listener != null) {
             activityPluginBinding.removeRequestPermissionsResultListener(listener)
         }
-
     }
 
     @ExperimentalGetImage
@@ -173,11 +175,13 @@ class MobileScannerHandler(
                 torchStateCallback,
                 zoomScaleStateCallback,
                 mobileScannerStartedCallback = {
+                    Handler(Looper.getMainLooper()).post {
                         result.success(mapOf(
                             "textureId" to it.id,
                             "size" to mapOf("width" to it.width, "height" to it.height),
                             "torchable" to it.hasFlashUnit
                         ))
+                    }
                 },
                 timeout.toLong(),
                 cameraResolution,

@@ -9,9 +9,6 @@ import Flutter
 import Foundation
 
 public class BarcodeHandler: NSObject, FlutterStreamHandler {
-    
-    var event: [String: Any?] = [:]
-    
     private var eventSink: FlutterEventSink?
     private let eventChannel: FlutterEventChannel
     
@@ -23,8 +20,9 @@ public class BarcodeHandler: NSObject, FlutterStreamHandler {
     }
     
     func publishEvent(_ event: [String: Any?]) {
-        self.event = event
-        eventSink?(event)
+        DispatchQueue.main.async {
+            self.eventSink?(event)
+        }
     }
     
     public func onListen(withArguments arguments: Any?,

@@ -232,7 +232,6 @@ public class MobileScanner: NSObject, AVCaptureVideoDataOutputSampleBufferDelega
                     device.activeFormat.formatDescription)
                 let hasTorch = device.hasTorch
                 
-                DispatchQueue.main.async {
                 completion(
                     MobileScannerStartParameters(
                         width: Double(dimensions.height),
@@ -241,16 +240,13 @@ public class MobileScanner: NSObject, AVCaptureVideoDataOutputSampleBufferDelega
                         textureId: self.textureId ?? 0
                     )
                 )
-                }
                 
                 return
             }
             
-            DispatchQueue.main.async {
             completion(MobileScannerStartParameters())
         }
     }
-    }
 
     /// Stop scanning for barcodes
     func stop() throws {

@@ -121,7 +121,12 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin {
 
         do {
             try mobileScanner.start(barcodeScannerOptions: barcodeOptions, returnImage: returnImage, cameraPosition: position, torch: torch ? .on : .off, detectionSpeed: detectionSpeed) { parameters in
-                result(["textureId": parameters.textureId, "size": ["width": parameters.width, "height": parameters.height], "torchable": parameters.hasTorch])
+                DispatchQueue.main.async {
+                    result([
+                        "textureId": parameters.textureId,
+                        "size": ["width": parameters.width, "height": parameters.height],
+                        "torchable": parameters.hasTorch])
+                }
             }
         } catch MobileScannerError.alreadyStarted {
             result(FlutterError(code: "MobileScanner",
@@ -158,12 +163,12 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin {
     private func toggleTorch(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
         do {
             try mobileScanner.toggleTorch(call.arguments as? Int == 1 ? .on : .off)
+            result(nil)
         } catch {
             result(FlutterError(code: "MobileScanner",
                                 message: "Called toggleTorch() while stopped!",
                                 details: nil))
         }
-        result(nil)
     }
     
     /// Toggles the zoomScale
@@ -177,6 +182,7 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin {
         }
         do {
             try mobileScanner.setScale(scale!)
+            result(nil)
         } catch MobileScannerError.zoomWhenStopped {
             result(FlutterError(code: "MobileScanner",
                                 message: "Called setScale() while stopped!",
@@ -190,13 +196,13 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin {
                                 message: "Error while zooming.",
                                 details: nil))
         }
-        result(nil)
     }
 
     /// Reset the zoomScale
     private func resetScale(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
         do {
             try mobileScanner.resetScale()
+            result(nil)
         } catch MobileScannerError.zoomWhenStopped {
             result(FlutterError(code: "MobileScanner",
                                 message: "Called resetScale() while stopped!",
@@ -210,7 +216,6 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin {
                                 message: "Error while zooming.",
                                 details: nil))
         }
-        result(nil)
     }
 
     /// Toggles the torch
@@ -247,16 +252,28 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin {
         }
 
         mobileScanner.analyzeImage(image: uiImage!, position: AVCaptureDevice.Position.back, callback: { [self] barcodes, error in
-            if error == nil && barcodes != nil && !barcodes!.isEmpty {
+            if error != nil {
+                barcodeHandler.publishEvent(["name": "error", "message": error?.localizedDescription])
+                
+                DispatchQueue.main.async {
+                    result(false)
+                }
+                
+                return
+            }
+            
+            if (barcodes == nil || barcodes!.isEmpty) {
+                DispatchQueue.main.async {
+                    result(false)
+                }
+            } else {
                 let barcodesMap: [Any?] = barcodes!.compactMap { barcode in barcode.data }
                 let event: [String: Any?] = ["name": "barcode", "data": barcodesMap]
                 barcodeHandler.publishEvent(event)
+                
+                DispatchQueue.main.async {
                     result(true)
-            } else {
-                if error != nil {
-                    barcodeHandler.publishEvent(["name": "error", "message": error?.localizedDescription])
                 }
-                result(false)
             }
         })
     }

 import AVFoundation
-import Flutter
 import Foundation
 import MLKitBarcodeScanning
 
-extension Error {
-    func throwNative(_ result: FlutterResult) {
-        let error = FlutterError(code: localizedDescription, message: nil, details: nil)
-        result(error)
-    }
-}
-
 extension CVBuffer {
     var image: UIImage {
         let ciImage = CIImage(cvPixelBuffer: self)

@@ -144,8 +144,10 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
                                 }
                             }
                         } else {
+                            DispatchQueue.main.async {
                                 self?.sink?(FlutterError(code: "MobileScanner", message: error?.localizedDescription, details: nil))
                             }
+                        }
                     })
                     if(self?.symbologies.isEmpty == false){
                         // add the symbologies the user wishes to support
@@ -153,11 +155,13 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
                     }
                     try imageRequestHandler.perform([barcodeRequest])
                 } catch let e {
+                    DispatchQueue.main.async {
                         self?.sink?(FlutterError(code: "MobileScanner", message: e.localizedDescription, details: nil))
                     }
                 }
             }
         }
+    }
     
     func checkPermission(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
         if #available(macOS 10.14, *) {
@@ -276,6 +280,7 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
                 device.unlockForConfiguration()
             } catch {
                 result(FlutterError(code: error.localizedDescription, message: nil, details: nil))
+                return
             }
         }
         
@@ -288,6 +293,7 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
             captureSession.addInput(input)
         } catch {
             result(FlutterError(code: error.localizedDescription, message: nil, details: nil))
+            return
         }
         captureSession.sessionPreset = AVCaptureSession.Preset.photo
         // Add video output.