Allow to add weight entries from the dashboard

lib/widgets/dashboard/widgets.dart

@@ -28,8 +28,10 @@ import 'package:wger/providers/nutrition.dart';
 import 'package:wger/providers/workout_plans.dart';
 import 'package:wger/screens/nutritional_plan_screen.dart';
 import 'package:wger/screens/workout_plan_screen.dart';
+import 'package:wger/widgets/core/bottom_sheet.dart';
 import 'package:wger/widgets/nutrition/charts.dart';
 import 'package:wger/widgets/weight/charts.dart';
+import 'package:wger/widgets/weight/forms.dart';
 
 class DashboardNutritionWidget extends StatefulWidget {
   const DashboardNutritionWidget({
@@ -153,15 +155,15 @@ class _DashboardWeightWidgetState extends State<DashboardWeightWidget> {
                 mainAxisAlignment: MainAxisAlignment.end,
                 children: <Widget>[
                   TextButton(
-                    child: const Text('Action one'),
-                    onPressed: () {},
+                    child: Text(AppLocalizations.of(context).newEntry),
+                    onPressed: () async {
+                      showFormBottomSheet(
+                        context,
+                        AppLocalizations.of(context).newEntry,
+                        WeightForm(),
+                      );
+                    },
                   ),
-                  const SizedBox(width: 8),
-                  TextButton(
-                    child: const Text('Action two'),
-                    onPressed: () {},
-                  ),
-                  const SizedBox(width: 8),
                 ],
               ),
             ],

lib/widgets/weight/forms.dart

@@ -17,7 +17,7 @@ class WeightForm extends StatelessWidget {
 
   WeightForm([weightEntry]) {
     this._weightEntry = weightEntry ?? WeightEntry();
-    weightController.text = _weightEntry.weight.toString();
+    weightController.text = _weightEntry.weight == null ? '' : _weightEntry.weight.toString();
   }
 
   @override
@@ -59,6 +59,17 @@ class WeightForm extends StatelessWidget {
             onSaved: (newValue) {
               _weightEntry.weight = double.parse(newValue);
             },
+            validator: (value) {
+              if (value.isEmpty) {
+                return 'Please enter a weight';
+              }
+              try {
+                double.parse(value);
+              } catch (error) {
+                return 'Please enter a valid number';
+              }
+              return null;
+            },
           ),
           ElevatedButton(
             child: Text(AppLocalizations.of(context).save),