Fixed crash bug when a QR Code string could not be decoded and result…

Sources/QRCodeReader.swift

@@ -78,6 +78,9 @@ public final class QRCodeReader: NSObject, AVCaptureMetadataOutputObjectsDelegat
   /// Block is executed when a metadata object is found.
   public var didFindCode: ((QRCodeReaderResult) -> Void)?
 
+  /// Block is executed when a found metadata object string could not be decoded.
+  public var didFailDecoding: ((Void) -> Void)?
+
   // MARK: - Creating the Code Reade
 
   /**
@@ -332,20 +335,27 @@ public final class QRCodeReader: NSObject, AVCaptureMetadataOutputObjectsDelegat
 
   // MARK: - AVCaptureMetadataOutputObjects Delegate Methods
 
-
   public func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) {
     for current in metadataObjects {
       if let _readableCodeObject = current as? AVMetadataMachineReadableCodeObject {
-        if metadataObjectTypes.contains(_readableCodeObject.type) {
-          if stopScanningWhenCodeIsFound {
-            stopScanning()
+        if _readableCodeObject.stringValue != nil {
+          if metadataObjectTypes.contains(_readableCodeObject.type) {
+            if let sVal = _readableCodeObject.stringValue {
+              if stopScanningWhenCodeIsFound {
+                stopScanning()
+              }
+
+              let scannedResult = QRCodeReaderResult(value: sVal, metadataType:_readableCodeObject.type)
+
+              DispatchQueue.main.async(execute: { [weak self] in
+                self?.didFindCode?(scannedResult)
+              })
+            }
           }
-
-          let scannedResult = QRCodeReaderResult(value: _readableCodeObject.stringValue, metadataType:_readableCodeObject.type)
-
-          DispatchQueue.main.async(execute: { [weak self] in
-            self?.didFindCode?(scannedResult)
-            })
+        }
+        else {
+          NSLog("Could not retrieve a valid string value for code type \(_readableCodeObject.type)")
+          self.didFailDecoding?()
         }
       }
     }

Sources/QRCodeReaderView.swift

@@ -110,6 +110,30 @@ final class QRCodeReaderView: UIView, QRCodeReaderDisplayable {
     }
   }
 
+  // MARK: - Scan Result Indication
+
+  func startTimerForBorderReset() {
+    DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + .seconds(1)) {
+      if let ovl = self.overlayView as? ReaderOverlayView {
+        ovl.overlayColor = .white
+      }
+    }
+  }
+
+  func addRedBorder() {
+    self.startTimerForBorderReset()
+    if let ovl = self.overlayView as? ReaderOverlayView {
+      ovl.overlayColor = .red
+    }
+  }
+
+  func addGreenBorder() {
+    self.startTimerForBorderReset()
+    if let ovl = self.overlayView as? ReaderOverlayView {
+      ovl.overlayColor = .green
+    }
+  }
+
   // MARK: - Convenience Methods
 
   private func addComponents() {

Sources/QRCodeReaderViewController.swift

@@ -75,11 +75,22 @@ public class QRCodeReaderViewController: UIViewController {
 
     codeReader.didFindCode = { [weak self] resultAsObject in
       if let weakSelf = self {
+        if let qrv = weakSelf.readerView.displayable as? QRCodeReaderView {
+          qrv.addGreenBorder()
+        }
         weakSelf.completionBlock?(resultAsObject)
         weakSelf.delegate?.reader(weakSelf, didScanResult: resultAsObject)
       }
     }
 
+    codeReader.didFailDecoding = { [weak self] in
+      if let weakSelf = self {
+        if let qrv = weakSelf.readerView.displayable as? QRCodeReaderView {
+          qrv.addRedBorder()
+        }
+      }
+    }
+
     setupUIComponentsWithCancelButtonTitle(builder.cancelButtonTitle)
 
     NotificationCenter.default.addObserver(self, selector: #selector(orientationDidChange), name: NSNotification.Name.UIDeviceOrientationDidChange, object: nil)

Sources/ReaderOverlayView.swift

@@ -56,6 +56,13 @@ public final class ReaderOverlayView: UIView {
     layer.addSublayer(overlay)
   }
 
+  var overlayColor: UIColor = UIColor.white {
+    didSet {
+      self.overlay.strokeColor = overlayColor.cgColor
+      self.setNeedsDisplay()
+    }
+  }
+
   public override func draw(_ rect: CGRect) {
     var innerRect = rect.insetBy(dx: 50, dy: 50)
     let minSize   = min(innerRect.width, innerRect.height)