null safety

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),