null safety

lib/pages/widgets/local_radio_buttons.dart

@@ -3,15 +3,15 @@ import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 
 class LocalRadioButtons<T> extends StatelessWidget {
-  final Function(T) callback;
-  final IconData iconData;
-  final T selectedValue;
-  final List<T> values;
+  final Function(T)? callback;
+  final IconData? iconData;
+  final T? selectedValue;
+  final List<T>? values;
   final bool readOnly;
   final bool hideUnselected;
 
   const LocalRadioButtons(
-      {Key key,
+      {Key? key,
       this.callback,
       this.iconData,
       this.selectedValue,
@@ -26,19 +26,19 @@ class LocalRadioButtons<T> extends StatelessWidget {
   }
 
   List<Widget> getChildren() {
-    return values
+    return values!
         .toList()
         .map((e) => SizedBox(
             height: 30,
             child: InkWell(
-              onTap: () => callback(e),
+              onTap: () => callback!(e),
               child: Row(children: <Widget>[
                 Radio<T>(
                   activeColor: primaryColor,
                   groupValue: selectedValue,
                   value: e,
-                  onChanged: (T value) {
-                    callback(value);
+                  onChanged: (T? value) {
+                    callback!(value!);
                   },
                 ),
                 Text(e.toString()),
@@ -48,7 +48,7 @@ class LocalRadioButtons<T> extends StatelessWidget {
   }
 
   List<Widget> getReadonlyChildren() {
-    return values
+    return values!
         .toList()
         .map((e) => hideUnselected && e == selectedValue
             ? SizedBox(