added scroll controller in forms

lib/src/pages/operating_system_selection.dart

@@ -16,6 +16,7 @@ class OperatingSystemSelection extends StatefulWidget {
 class _OperatingSystemSelectionState extends State<OperatingSystemSelection> {
   var term = "";
   final focusNode = FocusNode();
+  final ScrollController _scrollController = ScrollController();
 
   @override
   void initState() {
@@ -23,6 +24,12 @@ class _OperatingSystemSelectionState extends State<OperatingSystemSelection> {
     super.initState();
   }
 
+  @override
+  void dispose() {
+    _scrollController.dispose();
+    super.dispose();
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
@@ -63,19 +70,18 @@ class _OperatingSystemSelectionState extends State<OperatingSystemSelection> {
           ),
         ),
       ),
-      body: SingleChildScrollView(
+      body: Scrollbar(
-        child: Column(
+        controller: _scrollController,
-          children: [
+        child: FutureBuilder(
-            FutureBuilder(
           future: gOperatingSystems,
           builder: (BuildContext context, AsyncSnapshot<List> snapshot) {
             if (snapshot.hasData) {
               List list = snapshot.data!
-                      .where((os) => os.name.toLowerCase().contains(term.toLowerCase()))
+                  .where((os) =>
+                      os.name.toLowerCase().contains(term.toLowerCase()))
                   .toList();
               return ListView.builder(
-                    padding: const EdgeInsets.only(top: 4),
+                controller: _scrollController,
-                    shrinkWrap: true,
                 itemCount: list.length,
                 itemBuilder: (context, index) {
                   var item = list[index];
@@ -88,7 +94,6 @@ class _OperatingSystemSelectionState extends State<OperatingSystemSelection> {
                       height: 32,
                     );
                   } else {
-                        // Replace with generic icon
                     icon = const Icon(Icons.computer, size: 32);
                   }
                   return Card(
@@ -103,24 +108,18 @@ class _OperatingSystemSelectionState extends State<OperatingSystemSelection> {
                 },
               );
             } else {
-                  return Row(
+              return Center(
+                child: Column(
                   mainAxisAlignment: MainAxisAlignment.center,
                   children: [
-                      Column(
+                    const CircularProgressIndicator(),
-                        children: [
+                    const SizedBox(height: 16),
-                          const Padding(
-                              padding: EdgeInsets.all(16.0),
-                              child: CircularProgressIndicator()
-                          ),
                     Text(context.t('Loading available downloads')),
                   ],
-                      )
+                ),
-                    ],
               );
             }
-              }
+          },
-            ),
-          ]
         ),
       ),
     );

lib/src/pages/option_selection.dart

@@ -15,6 +15,7 @@ class OptionSelection extends StatefulWidget {
 class _OptionSelectionState extends State<OptionSelection> {
   var term = "";
   final focusNode = FocusNode();
+  final ScrollController _scrollController = ScrollController();
 
   @override
   void initState() {
@@ -22,6 +23,12 @@ class _OptionSelectionState extends State<OptionSelection> {
     super.initState();
   }
 
+  @override
+  void dispose() {
+    _scrollController.dispose();
+    super.dispose();
+  }
+
   @override
   Widget build(BuildContext context) {
     var list = widget.version.options
@@ -68,11 +75,10 @@ class _OptionSelectionState extends State<OptionSelection> {
                 ),
               ),
       ),
-      body: SingleChildScrollView(
+      body: Scrollbar(
-        child: Column(
+        controller: _scrollController,
-          children: [
+        child: ListView.builder(
-            ListView.builder(
+          controller: _scrollController,
-              shrinkWrap: true,
           itemCount: list.length,
           itemBuilder: (context, index) {
             var item = list[index];
@@ -86,8 +92,6 @@ class _OptionSelectionState extends State<OptionSelection> {
             );
           },
         ),
-          ],
-        ),
       ),
     );
   }

lib/src/pages/version_selection.dart

@@ -19,6 +19,7 @@ class VersionSelection extends StatefulWidget {
 class _VersionSelectionState extends State<VersionSelection> {
   var term = "";
   final focusNode = FocusNode();
+  final ScrollController _scrollController = ScrollController();
 
   @override
   void initState() {
@@ -26,6 +27,12 @@ class _VersionSelectionState extends State<VersionSelection> {
     super.initState();
   }
 
+  @override
+  void dispose() {
+    _scrollController.dispose();
+    super.dispose();
+  }
+
   @override
   Widget build(BuildContext context) {
     var list = widget.operatingSystem.versions
@@ -73,12 +80,11 @@ class _VersionSelectionState extends State<VersionSelection> {
           ),
         ),
       ),
-      body: SingleChildScrollView(
+      body: Scrollbar(
-        child: Column(
+        controller: _scrollController,
-          children: [
+        child: ListView.builder(
-            ListView.builder(
+          controller: _scrollController,
           padding: const EdgeInsets.only(top: 4),
-              shrinkWrap: true,
           itemCount: list.length,
           itemBuilder: (context, index) {
             var item = list[index];
@@ -90,8 +96,7 @@ class _VersionSelectionState extends State<VersionSelection> {
                     Navigator.of(context)
                         .push<Option>(MaterialPageRoute(
                             fullscreenDialog: true,
-                                builder: (context) =>
+                            builder: (context) => OptionSelection(list[index])))
-                                    OptionSelection(list[index])))
                         .then((selection) {
                       if (selection != null) {
                         Navigator.of(context)
@@ -99,16 +104,14 @@ class _VersionSelectionState extends State<VersionSelection> {
                       }
                     });
                   } else {
-                        Navigator.of(context).pop(Tuple2<Version, Option?>(
+                    Navigator.of(context).pop(
-                            item, list[index].options[0]));
+                        Tuple2<Version, Option?>(item, list[index].options[0]));
                   }
                 },
               ),
             );
           },
         ),
-          ],
-        ),
       ),
     );
   }