Manually update to null safe - step2

apply some simple fixes like:
1. adding "late"
2. adding "?"/"!"

lib/generated_plugin_registrant.dart

@@ -2,6 +2,7 @@
 // Generated file. Do not edit.
 //
 
+// ignore_for_file: directives_ordering
 // ignore_for_file: lines_longer_than_80_chars
 
 import 'package:cloud_firestore_web/cloud_firestore_web.dart';

lib/my_route_search_delegate.dart

@@ -29,7 +29,7 @@ class MyRouteSearchDelegate extends SearchDelegate<String> {
     return IconButton(
       tooltip: 'Back',
       icon: const Icon(Icons.arrow_back),
-      onPressed: () => this.close(context, null),
+      onPressed: () => this.close(context, ''),
     );
   }
 

lib/routes/animation_animated_builder_ex.dart

@@ -10,7 +10,7 @@ class AnimatedBuilderExample extends StatefulWidget {
 
 class _AnimatedBuilderExampleState extends State<AnimatedBuilderExample>
     with SingleTickerProviderStateMixin {
-  AnimationController _controller;
+  late AnimationController _controller;
 
   @override
   void initState() {

lib/routes/animation_animated_icons_ex.dart

@@ -57,7 +57,7 @@ class _AnimIconDemoBox extends StatefulWidget {
 // ! Add SingleTickerProviderStateMixin to use animation controllers.
 class _AnimIconDemoBoxState extends State<_AnimIconDemoBox>
     with SingleTickerProviderStateMixin {
-  AnimationController _animationController;
+  late AnimationController _animationController;
 
   @override
   void initState() {

lib/routes/animation_animated_text_kit_ex.dart

@@ -21,7 +21,7 @@ class AnimatedTextKitExample extends StatelessWidget {
         TextLiquidFill(
           text: 'LIQUIDY',
           waveColor: Colors.blueAccent,
-          boxBackgroundColor: Colors.red[100],
+          boxBackgroundColor: Colors.red[100]!,
           textStyle:
               const TextStyle(fontSize: 80.0, fontWeight: FontWeight.bold),
           boxHeight: 300.0,

lib/routes/animation_animated_widget_ex.dart

@@ -3,7 +3,7 @@ import 'package:flutter/material.dart';
 // The AnimatedWidget base class allows you to separate out the core widget code
 // from the animation code.
 class _AnimatedLogo extends AnimatedWidget {
-  const _AnimatedLogo({Key? key, Animation<double> animation})
+  const _AnimatedLogo({Key? key, required Animation<double> animation})
       : super(key: key, listenable: animation);
 
   @override
@@ -28,8 +28,8 @@ class AnimatedWidgetExample extends StatefulWidget {
 
 class _AnimatedWidgetExampleState extends State<AnimatedWidgetExample>
     with SingleTickerProviderStateMixin {
-  Animation<double> _sizeAnimation;
-  AnimationController _controller;
+  late Animation<double> _sizeAnimation;
+  late AnimationController _controller;
 
   @override
   void initState() {

lib/routes/animation_animations_pkg_ex.dart

@@ -232,8 +232,9 @@ class __SharedAxisExState extends State<_SharedAxisEx> {
                         .substring('SharedAxisTransitionType.'.length)),
                   )
               ],
-              onChanged: (SharedAxisTransitionType val) =>
-                  setState(() => this._transitionType = val),
+              onChanged: (SharedAxisTransitionType? val) {
+                if (val != null) setState(() => this._transitionType = val);
+              },
             ),
           ),
         ],

lib/routes/animation_lottie_ex.dart

@@ -31,7 +31,7 @@ class _LottieCustom extends StatefulWidget {
 
 class __LottieCustomState extends State<_LottieCustom>
     with TickerProviderStateMixin {
-  AnimationController _controller;
+  late AnimationController _controller;
 
   @override
   void initState() {

lib/routes/animation_low_level_ex.dart

@@ -15,14 +15,14 @@ class _LowLevelAnimationExampleState extends State<LowLevelAnimationExample>
   // An Animation object knows the current state of an animation (for example,
   // whether it’s started, stopped, or moving forward or in reverse), but
   // doesn’t know anything about what appears onscreen.
-  Animation<double> _sizeAnimation;
-  Animation<Color> _colorAnimation;
+  late Animation<double> _sizeAnimation;
+  late Animation<Color?> _colorAnimation;
   // Both AnimationController and CurvedAnimation extends Animation<double>,
   // but add additional methods
   // An AnimationController manages the Animation.
-  AnimationController _controller;
+  late AnimationController _controller;
   // A CurvedAnimation defines progression as a non-linear curve.
-  CurvedAnimation _curve;
+  late CurvedAnimation _curve;
 
   @override
   void initState() {

lib/routes/appbar_bottom_appbar_ex.dart

@@ -26,7 +26,7 @@ class _BottomAppbarExampleState extends State<BottomAppbarExample> {
             title: const Text('FloatingActionButton position:'),
             trailing: DropdownButton<FloatingActionButtonLocation>(
               value: this._fabLocation,
-              onChanged: (FloatingActionButtonLocation newVal) {
+              onChanged: (FloatingActionButtonLocation? newVal) {
                 if (newVal != null) {
                   setState(() => this._fabLocation = newVal);
                 }

lib/routes/appbar_convex_appbar_ex.dart

@@ -58,7 +58,7 @@ class _ConvexAppExampleState extends State<ConvexAppExample> {
     final dropdown = DropdownButton<TabStyle>(
       value: _tabStyle,
       onChanged: (newStyle) {
-        setState(() => _tabStyle = newStyle);
+        if (newStyle != null) setState(() => _tabStyle = newStyle);
       },
       items: [
         for (final style in TabStyle.values)

lib/routes/appbar_search_ex.dart

@@ -12,7 +12,7 @@ class AppBarSearchExample extends StatefulWidget {
 
 class _AppBarSearchExampleState extends State<AppBarSearchExample> {
   final List<String> kEnglishWords;
-  _MySearchDelegate _delegate;
+  late _MySearchDelegate _delegate;
 
   _AppBarSearchExampleState()
       : kEnglishWords = List.from(Set.from(english_words.all))
@@ -38,7 +38,7 @@ class _AppBarSearchExampleState extends State<AppBarSearchExample> {
             tooltip: 'Search',
             icon: const Icon(Icons.search),
             onPressed: () async {
-              final String selected = await showSearch<String>(
+              final String? selected = await showSearch<String>(
                 context: context,
                 delegate: _delegate,
               );
@@ -87,7 +87,7 @@ class _MySearchDelegate extends SearchDelegate<String> {
       ),
       onPressed: () {
         // SearchDelegate.close() can return vlaues, similar to Navigator.pop().
-        this.close(context, null);
+        this.close(context, '');
       },
     );
   }
@@ -112,7 +112,7 @@ class _MySearchDelegate extends SearchDelegate<String> {
                 this.query,
                 style: Theme.of(context)
                     .textTheme
-                    .headline4
+                    .headline4!
                     .copyWith(fontWeight: FontWeight.bold),
               ),
             ),
@@ -167,15 +167,18 @@ class _MySearchDelegate extends SearchDelegate<String> {
 
 // Suggestions list widget displayed in the search page.
 class _SuggestionList extends StatelessWidget {
-  const _SuggestionList({this.suggestions, this.query, this.onSelected});
+  const _SuggestionList(
+      {required this.suggestions,
+      required this.query,
+      required this.onSelected});
 
   final List<String> suggestions;
   final String query;
   final ValueChanged<String> onSelected;
 
   @override
   Widget build(BuildContext context) {
-    final textTheme = Theme.of(context).textTheme.subtitle1;
+    final textTheme = Theme.of(context).textTheme.subtitle1!;
     return ListView.builder(
       itemCount: suggestions.length,
       itemBuilder: (BuildContext context, int i) {

lib/routes/async_futurebuilder_ex.dart

@@ -37,7 +37,7 @@ class FutureBuilderExampleState extends State<FutureBuilderExample> {
                 // This shouldn't happen in our case, but good to handle errors.
                 return const Text('Error has happened in the future!');
               } else {
-                return Image.memory(snapshot.data.buffer.asUint8List());
+                return Image.memory(snapshot.data!.buffer.asUint8List());
               }
             },
           ),

lib/routes/async_streambuilder_ex.dart

@@ -33,7 +33,7 @@ class StreamBuilderExampleState extends State<StreamBuilderExample> {
           if (snapshot.hasData) {
             if (snapshot.data != this._previousStreamValue) {
               print('Latest snapshot from stream: ${snapshot.data}');
-              this._previousStreamValue = snapshot.data;
+              this._previousStreamValue = snapshot.data!;
               if (!_paused) {
                 this._timerValue++;
               }

lib/routes/async_streamcontroller_ex.dart

@@ -67,7 +67,7 @@ class _StreamControllerExampleState extends State<StreamControllerExample> {
                   title: Text('no data'),
                 );
               }
-              final Widget widgetToRender = snapshot.data;
+              final Widget widgetToRender = snapshot.data!;
               return widgetToRender;
             },
           ),

lib/routes/charts_fl_bar_chart_ex.dart

@@ -26,7 +26,7 @@ class _FlBarChartExampleState extends State<FlBarChartExample> {
           x: entry.key.toInt(),
           barRods: [
             BarChartRodData(y: entry.value, colors: [Colors.blue]),
-            BarChartRodData(y: _data2[entry.key], colors: [Colors.red]),
+            BarChartRodData(y: _data2[entry.key]!, colors: [Colors.red]),
           ],
         ),
     ];

lib/routes/charts_fl_line_chart_ex.dart

@@ -43,7 +43,7 @@ class _FlLineChartExampleState extends State<FlLineChartExample> {
           isCurved: _isCurved,
           dotData: FlDotData(show: _showDot),
           belowBarData:
-              BarAreaData(show: _showBelowArea, colors: [Colors.blue[200]]),
+              BarAreaData(show: _showBelowArea, colors: [Colors.blue[200]!]),
         ),
         LineChartBarData(
           spots: spots2,
@@ -52,7 +52,7 @@ class _FlLineChartExampleState extends State<FlLineChartExample> {
           isCurved: _isCurved,
           dotData: FlDotData(show: _showDot),
           belowBarData:
-              BarAreaData(show: _showBelowArea, colors: [Colors.red[200]]),
+              BarAreaData(show: _showBelowArea, colors: [Colors.red[200]!]),
         ),
       ],
       // ! Behavior when touching the chart:

lib/routes/charts_fl_pie_chart_ex.dart

@@ -46,7 +46,9 @@ class _FlPieChartExampleState extends State<FlPieChartExample> {
       pieTouchData: PieTouchData(
         enabled: true,
         touchCallback: (pieTouchResponse) => setState(() {
-          _touchedIdx = pieTouchResponse.touchedSection.touchedSectionIndex;
+          if (pieTouchResponse.touchedSection != null) {
+            _touchedIdx = pieTouchResponse.touchedSection!.touchedSectionIndex;
+          }
         }),
       ),
       centerSpaceRadius: _innerRadius,

lib/routes/charts_heatmap_calendar_ex.dart

@@ -36,7 +36,7 @@ class HeatmapCalendarExample extends StatelessWidget {
           squareSize: 18,
           textOpacity: 0.3,
           labelTextColor: Colors.blueGrey,
-          dayTextColor: Colors.blue[500],
+          dayTextColor: Colors.blue[500]!,
           // Week day and month labels can be overriden:
           // weekDaysLabels: const ['S', 'M', 'T', 'W', 'T', 'F', 'S'],
           // monthsLabels: const ['', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',

lib/routes/charts_pie_chart_ex.dart

@@ -47,7 +47,7 @@ class _PieChartExampleState extends State<PieChartExample> {
             /*seriesList=*/ [
               charts.Series<_CostsData, String>(
                 id: 'Sales-1',
-                colorFn: (_, idx) => _colorPalettes[idx].shadeDefault,
+                colorFn: (_, idx) => _colorPalettes[idx!].shadeDefault,
                 domainFn: (_CostsData sales, _) => sales.category,
                 measureFn: (_CostsData sales, _) => sales.cost,
                 data: this._data,
@@ -107,7 +107,7 @@ class _PieChartExampleState extends State<PieChartExample> {
           title: const Text('arcLabelPosition:'),
           trailing: DropdownButton<charts.ArcLabelPosition>(
             value: this._arcLabelPosition,
-            onChanged: (charts.ArcLabelPosition newVal) {
+            onChanged: (charts.ArcLabelPosition? newVal) {
               if (newVal != null) {
                 setState(() => this._arcLabelPosition = newVal);
               }
@@ -122,7 +122,7 @@ class _PieChartExampleState extends State<PieChartExample> {
           title: const Text('titlePosition:'),
           trailing: DropdownButton<charts.BehaviorPosition>(
             value: this._titlePosition,
-            onChanged: (charts.BehaviorPosition newVal) {
+            onChanged: (charts.BehaviorPosition? newVal) {
               if (newVal != null) {
                 setState(() => this._titlePosition = newVal);
               }
@@ -137,7 +137,7 @@ class _PieChartExampleState extends State<PieChartExample> {
           title: const Text('legendPosition:'),
           trailing: DropdownButton<charts.BehaviorPosition>(
             value: this._legendPosition,
-            onChanged: (charts.BehaviorPosition newVal) {
+            onChanged: (charts.BehaviorPosition? newVal) {
               if (newVal != null) {
                 setState(() => this._legendPosition = newVal);
               }

lib/routes/charts_time_series_ex.dart

@@ -41,7 +41,7 @@ class _TimeseriesChartExampleState extends State<TimeseriesChartExample> {
   charts.BehaviorPosition _legendPosition = charts.BehaviorPosition.bottom;
 
   // Data to render.
-  List<_SalesData> _series1, _series2;
+  late List<_SalesData> _series1, _series2;
 
   @override
   void initState() {
@@ -135,7 +135,7 @@ class _TimeseriesChartExampleState extends State<TimeseriesChartExample> {
           title: const Text('titlePosition:'),
           trailing: DropdownButton<charts.BehaviorPosition>(
             value: this._titlePosition,
-            onChanged: (charts.BehaviorPosition newVal) {
+            onChanged: (charts.BehaviorPosition? newVal) {
               if (newVal != null) {
                 setState(() => this._titlePosition = newVal);
               }
@@ -150,7 +150,7 @@ class _TimeseriesChartExampleState extends State<TimeseriesChartExample> {
           title: const Text('legendPosition:'),
           trailing: DropdownButton<charts.BehaviorPosition>(
             value: this._legendPosition,
-            onChanged: (charts.BehaviorPosition newVal) {
+            onChanged: (charts.BehaviorPosition? newVal) {
               if (newVal != null) {
                 setState(() => this._legendPosition = newVal);
               }

lib/routes/data/todo_item.dart

@@ -6,16 +6,20 @@ part 'todo_item.g.dart';
 @HiveType(typeId: 0)
 class TodoItem extends HiveObject {
   @HiveField(0)
-  int id;
+  int? id;
   @HiveField(1)
   String content;
   @HiveField(2)
   bool isDone;
   @HiveField(3)
   final DateTime createdAt;
 
-  TodoItem({this.id, this.content, this.isDone = false, DateTime createdAt})
-      : this.createdAt = createdAt ?? DateTime.now();
+  TodoItem({
+    this.id,
+    required this.content,
+    this.isDone = false,
+    DateTime? createdAt,
+  }) : this.createdAt = createdAt ?? DateTime.now();
 
   @override
   String toString() {

lib/routes/firebase_chatroom_ex.dart

@@ -19,8 +19,8 @@ class FirebaseChatroomExample extends StatefulWidget {
 }
 
 class _FirebaseChatroomExampleState extends State<FirebaseChatroomExample> {
-  firebase_auth.User _user;
-  DatabaseReference _firebaseMsgDbRef;
+  firebase_auth.User? _user;
+  late DatabaseReference _firebaseMsgDbRef;
 
   final TextEditingController _textController = TextEditingController();
   bool _isComposing = false;
@@ -49,7 +49,7 @@ class _FirebaseChatroomExampleState extends State<FirebaseChatroomExample> {
           scrollDirection: Axis.horizontal,
           child: Text(_user == null
               ? 'Chatting'
-              : 'Chatting as "${_user.displayName}"'),
+              : 'Chatting as "${_user!.displayName}"'),
         ),
       ),
       body: Center(
@@ -91,7 +91,7 @@ class _FirebaseChatroomExampleState extends State<FirebaseChatroomExample> {
         child: FirebaseAnimatedList(
           defaultChild: const Center(child: CircularProgressIndicator()),
           query: _firebaseMsgDbRef,
-          sort: (a, b) => b.key.compareTo(a.key),
+          sort: (a, b) => b.key!.compareTo(a.key!),
           padding: const EdgeInsets.all(8.0),
           reverse: true,
           itemBuilder: (BuildContext ctx, DataSnapshot snapshot,
@@ -214,9 +214,9 @@ class _FirebaseChatroomExampleState extends State<FirebaseChatroomExample> {
     });
     // Send message to firebase realtime database.
     _firebaseMsgDbRef.push().set({
-      'senderId': this._user.uid,
-      'senderName': this._user.displayName,
-      'senderPhotoUrl': this._user.photoURL,
+      'senderId': this._user!.uid,
+      'senderName': this._user!.displayName,
+      'senderPhotoUrl': this._user!.photoURL,
       'text': text,
       'timestamp': DateTime.now().millisecondsSinceEpoch,
     });