null safety

lib/pages/main/home_page.dart

@@ -36,7 +36,7 @@ import 'package:fcs/pages/widgets/right_left_page_rout.dart';
 import 'package:fcs/pages/widgets/task_button.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter_icons/flutter_icons.dart';
+import 'package:flutter_vector_icons/flutter_vector_icons.dart';
 import 'package:flutter_local_notifications/flutter_local_notifications.dart';
 import 'package:font_awesome_flutter/font_awesome_flutter.dart';
 import 'package:logging/logging.dart';
@@ -94,7 +94,7 @@ class _HomePageState extends State<HomePage> {
     });
   }
 
-  String notiUserID, notiUserName;
+  late String notiUserID, notiUserName;
   _showNotiContent(Map<String, dynamic> message) {
     try {
       Map<String, dynamic> map = Map<String, dynamic>.from(message["data"]);
@@ -291,7 +291,7 @@ class _HomePageState extends State<HomePage> {
 
     final staffBtn = TaskButton(
       "staff.title",
-      icon: MaterialCommunityIcons.worker,
+      icon: MaterialCommunityIcons.account_tie,
       btnCallback: () => Navigator.of(context).push<void>(CupertinoPageRoute(
         builder: (context) => StaffList(),
       )),
@@ -350,7 +350,7 @@ class _HomePageState extends State<HomePage> {
       selectedColor: Colors.white,
       color: Colors.blue,
       children: <Widget>[
-        Icon(MaterialCommunityIcons.worker),
+        Icon(MaterialCommunityIcons.account_tie),
       ],
       onPressed: (i) => this.setState(() {
         isFcs[0] = !isFcs[0];

lib/pages/main/initial_language_selection.dart

@@ -27,9 +27,9 @@ class _InitialLanguageSelectionPageState
     languagesList[1]: languageCodesList[1],
   };
 
-  String selectedLanguage;
-  int selectedIndex;
-  bool _isLoading;
+  late String selectedLanguage;
+  late int selectedIndex;
+  bool _isLoading = false;
 
   @override
   void initState() {
@@ -102,8 +102,8 @@ class _InitialLanguageSelectionPageState
                                   ? BoxDecoration()
                                   : BoxDecoration(
                                       border: Border(
-                                        bottom:
-                                            BorderSide(color: Colors.grey[300]),
+                                        bottom: BorderSide(
+                                            color: Colors.grey.shade300),
                                       ),
                                     ),
                               child: ListTile(
@@ -134,7 +134,7 @@ class _InitialLanguageSelectionPageState
                                     child: Radio(
                                       value: key,
                                       groupValue: selectedIndex,
-                                      onChanged: (int i) =>
+                                      onChanged: (int? i) =>
                                           _select(key, language),
                                       activeColor: primaryColor,
                                     ),
@@ -178,7 +178,7 @@ class _InitialLanguageSelectionPageState
     setState(() {
       selectedIndex = index;
       selectedLanguage = lang;
-      Translation().onLocaleChanged(Locale(languagesMap[lang]));
+      Translation().onLocaleChanged!(Locale(languagesMap[lang]));
       Provider.of<LanguageModel>(context, listen: false)
           .saveLanguage(selectedLanguage);
     });

lib/pages/main/splash_page.dart

@@ -18,7 +18,7 @@ class _SplashScreenState extends State<SplashScreen> {
   bool _loaded = false;
   bool _isSupport = false;
   bool _isOnline = true;
-  Timer timer;
+  late Timer timer;
 
   startTime() async {
     var _duration = new Duration(milliseconds: 3000);

lib/pages/main/util.dart

@@ -33,7 +33,7 @@ Future showMsgDialog(BuildContext context, String title, String msg) {
 
 Future<void> showConfirmDialog(
     BuildContext context, String translationKey, ok(),
-    {List<String> translationVariables}) async {
+    {List<String>? translationVariables}) async {
   await showDialog(
       context: context,
       builder: (_) {
@@ -42,7 +42,7 @@ Future<void> showConfirmDialog(
             child: LocalText(
               context,
               translationKey,
-              translationVariables: translationVariables,
+              translationVariables: translationVariables!,
               color: primaryColor,
             ),
           ),
@@ -188,7 +188,7 @@ Widget getStatus(String status) {
                                               ],
                                             )
                                           : Text(
-                                              status ?? "",
+                                              status,
                                               style: TextStyle(
                                                   color: primaryColor,
                                                   fontSize: 18,
@@ -230,10 +230,10 @@ Widget phoneWidget(BuildContext context, String phone) {
 }
 
 Widget fcsInput(String label, IconData iconData,
-    {TextEditingController controller,
-    String value,
+    {required TextEditingController controller,
+    required String value,
     bool autoFocus = false,
-    TextInputType textInputType}) {
+    TextInputType? textInputType}) {
   return TextFormField(
       initialValue: value,
       controller: controller,
@@ -257,7 +257,7 @@ Widget fcsInput(String label, IconData iconData,
 }
 
 Widget fcsInputReadOnly(String label, IconData iconData,
-    {TextEditingController controller, String value}) {
+    {required TextEditingController controller, required String value}) {
   return TextFormField(
       initialValue: value,
       controller: controller,
@@ -279,7 +279,7 @@ Widget fcsInputReadOnly(String label, IconData iconData,
 }
 
 Widget fcsDropDown(String label, IconData iconData,
-    {TextEditingController controller}) {
+    {required TextEditingController controller}) {
   return Row(
     children: <Widget>[
       Padding(
@@ -308,7 +308,7 @@ Widget _dropDown() {
       height: 2,
       color: primaryColor,
     ),
-    onChanged: (String newValue) {},
+    onChanged: (String? newValue) {},
     items: <String>['Ko Nge', 'Two', 'Free', 'Four']
         .map<DropdownMenuItem<String>>((String value) {
       return DropdownMenuItem<String>(
@@ -320,7 +320,7 @@ Widget _dropDown() {
 }
 
 Widget fcsButton(BuildContext context, String text,
-    {Function callack, IconData iconData}) {
+    {Function? callack, IconData? iconData}) {
   var languageModel = Provider.of<LanguageModel>(context);
 
   var style = languageModel.isEng
@@ -344,7 +344,7 @@ Widget fcsButton(BuildContext context, String text,
         minWidth: 900.0,
         height: 100.0,
         child: FlatButton(
-          onPressed: callack,
+          onPressed: callack == null ? null : () => callack(),
           child: Row(
             mainAxisAlignment: MainAxisAlignment.center,
             children: [
@@ -371,7 +371,7 @@ String getLocalString(BuildContext context, String key) {
 }
 
 void showToast(GlobalKey key, String text) {
-  final ScaffoldState scaffold = key.currentState;
+  final ScaffoldState scaffold = key.currentState as ScaffoldState;
   scaffold.showSnackBar(
     SnackBar(
       content: Text(text),

lib/pages/main/welcome_page.dart

@@ -24,7 +24,7 @@ typedef BtnCallback();
 class _WelcomePageState extends State<WelcomePage> {
   final log = Logger('_HomePageWelcomeState');
 
-  String pin;
+  late String pin;
   List<bool> isSelected = [true, false];
 
   @override