Add barcode handler to scan stock item into location

lib/barcode.dart

@@ -339,6 +339,40 @@ class _QRViewState extends State<InvenTreeQRView> {
 }
 
 
+class StockItemScanIntoLocationHandler extends BarcodeHandler {
+  /**
+   * Barcode handler for scanning a provided StockItem into a scanned StockLocation
+   */
+
+  final InvenTreeStockItem item;
+
+  StockItemScanIntoLocationHandler(this.item);
+
+  @override
+  Future<void> onBarcodeMatched(Map<String, dynamic> data) {
+    // If the barcode points to a 'stocklocation', great!
+    if (!data.containsKey('stocklocation')) {
+      showErrorDialog(
+          _context,
+          "Invalid Barcode",
+          "Barcode does not match a Stock Location",
+          onDismissed: _controller.resumeCamera,
+      );
+     } else {
+      // Extract location information
+      int location = data['stocklocation']['pk'] as int;
+
+      // Transfer stock to specified location
+      item.transferStock(location).then((response) {
+        print("Response: ${response.statusCode}");
+        _controller.dispose();
+        Navigator.of(_context).pop();
+      });
+    }
+  }
+}
+
+
 Future<void> scanQrCode(BuildContext context) async {
 
   Navigator.push(context, MaterialPageRoute(builder: (context) => InvenTreeQRView(BarcodeScanHandler())));

lib/inventree/stock.dart

@@ -379,20 +379,26 @@ class InvenTreeStockItem extends InvenTreeModel {
     });
   }
 
-  Future<http.Response> transferStock(double q, int location, {String notes}) async {
+  Future<http.Response> transferStock(int location, {double quantity, String notes}) async {
+    if (quantity == null) {} else
+    if ((quantity < 0) || (quantity > this.quantity)) {
+      quantity = this.quantity;
+    }
 
-    if ((q == null) || (q > quantity)) q = quantity;
-
-    return api.post("/stock/transfer/", body: {
+    Map<String, dynamic> data = {
       "item": {
         "pk": "${pk}",
-        "quantity": "${q}",
-        },
+      },
       "location": "${location}",
       "notes": notes ?? '',
-    });
-  }
+    };
 
+    if (quantity != null) {
+      data["item"]["quantity"] = "${quantity}";
+    }
+
+    return api.post("/stock/transfer/", body: data);
+  }
 }
 
 

lib/widget/stock_detail.dart

@@ -253,7 +253,7 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
     _quantityController.clear();
     _notesController.clear();
 
-    var response = await item.transferStock(quantity, location.pk, notes: notes);
+    var response = await item.transferStock(location.pk, quantity: quantity, notes: notes);
 
     // TODO - Error handling (potentially return false?)
     refresh();
@@ -525,6 +525,10 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
         leading: FaIcon(FontAwesomeIcons.exchangeAlt),
         trailing: FaIcon(FontAwesomeIcons.qrcode),
         onTap: () {
+          Navigator.push(
+            context,
+            MaterialPageRoute(builder: (context) => InvenTreeQRView(StockItemScanIntoLocationHandler(item)))
+          );
         },
       )
     );