null safety

lib/pages/invoice/editor/invoice_editor.dart

@@ -103,10 +103,10 @@ class _InvoiceEditorState extends State<InvoiceEditor> {
   _loadShipments() async {
     ShipmentModel shipmentModel =
         Provider.of<ShipmentModel>(context, listen: false);
-    List<Shipment> shipments = await shipmentModel.getShipmentWithHandlingFee(
+    List<Shipment?>? shipments = await shipmentModel.getShipmentWithHandlingFee(
         widget.fcsShipment!.id!, widget.customer!.id!);
-    shipments.forEach((s) {
-      s.isSelected = true;
+    shipments!.forEach((s) {
+      s!.isSelected = true;
     });
     setState(() {
       _invoice!.shipments = shipments;
@@ -380,8 +380,8 @@ class _InvoiceEditorState extends State<InvoiceEditor> {
     if (shipment == null) return;
     shipment.isSelected = true;
     setState(() {
-      _invoice!.shipments.remove(shipment);
-      _invoice!.shipments.add(shipment);
+      _invoice!.shipments!.remove(shipment);
+      _invoice!.shipments!.add(shipment);
     });
   }
 
@@ -389,8 +389,8 @@ class _InvoiceEditorState extends State<InvoiceEditor> {
     if (shipment == null) return;
     shipment.isSelected = false;
     setState(() {
-      _invoice!.shipments.remove(shipment);
-      _invoice!.shipments.add(shipment);
+      _invoice!.shipments!.remove(shipment);
+      _invoice!.shipments!.add(shipment);
     });
   }
 
@@ -431,7 +431,7 @@ class _InvoiceEditorState extends State<InvoiceEditor> {
       invoice.handlingFee = _invoice!.getHandlingFee();
       invoice.cartons = _invoice!.cartons.where((c) => c.isChecked!).toList();
       invoice.shipments =
-          _invoice!.shipments.where((s) => s.isSelected).toList();
+          _invoice!.shipments!.where((s) => s!.isSelected).toList();
       invoice.discount = _invoice!.discount;
       invoice.deliveryFee = _invoice!.deliveryFee;
 

lib/pages/invoice/editor/invoice_handling_fee_list.dart

@@ -9,7 +9,7 @@ typedef OnAdd(Shipment shipment);
 typedef OnRemove(Shipment shipment);
 
 class InvoiceHandlingFeeList extends StatelessWidget {
-  final List<Shipment>? shipments;
+  final List<Shipment?>? shipments;
   final OnAdd? onAdd;
   final OnRemove? onRemove;
 
@@ -72,7 +72,7 @@ class InvoiceHandlingFeeList extends StatelessWidget {
         onSelectChanged: (value) => Navigator.pop(context, c),
         cells: [
           MyDataCell(new Text(
-            c.shipmentNumber!,
+            c!.shipmentNumber!,
             style: textStyle,
           )),
           MyDataCell(

lib/pages/invoice/invoice_info.dart

@@ -39,8 +39,8 @@ class _InvoiceInfoState extends State<InvoiceInfo> {
   void initState() {
     super.initState();
     _invoice = widget.invoice!;
-    _invoice!.shipments.forEach((s) {
-      s.isSelected = true;
+    _invoice!.shipments!.forEach((s) {
+      s!.isSelected = true;
     });
     _loadCartons();
   }

lib/pages/invoice/invoice_table.dart

@@ -70,11 +70,11 @@ class InvoiceTable extends StatelessWidget {
               "${c.calWeight.toStringAsFixed(2)} x ${c.calRate.toStringAsFixed(2)}",
           amount: "${c.calAmount.toStringAsFixed(2)}"));
     });
-    invoice!.shipments.where((ss) => (ss.isSelected )).forEach((s) {
+    invoice!.shipments!.where((ss) => (ss!.isSelected )).forEach((s) {
       tableRows.add(InvoiceTableRow(
           data: s,
           invoiceDataType: InvoiceDataType.HandlingFeeType,
-          desc: "Handling fee\n${s.shipmentNumber}",
+          desc: "Handling fee\n${s!.shipmentNumber}",
           rate: "",
           amount: "${s.handlingFee.toStringAsFixed(2)}"));
     });