diff --git a/example/lib/main.dart b/example/lib/main.dart
index e85b0fb1..857b9590 100644
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -20,7 +20,7 @@ class MyApp extends StatelessWidget {
 }
 
 class MyHomePage extends StatefulWidget {
-  MyHomePage({Key key}) : super(key: key);
+  MyHomePage({Key? key}) : super(key: key);
 
   @override
   _MyHomePageState createState() => _MyHomePageState();
@@ -69,7 +69,7 @@ class _MyHomePageState extends State<MyHomePage> {
             children: <Widget>[
               TextField(),
               TextField(),
-              ChipsInput(
+              ChipsInput<AppProfile>(
                 key: _chipKey,
                 /*initialValue: [
                   AppProfile('John Doe', 'jdoe@flutter.io',
@@ -199,14 +199,14 @@ class _MyHomePageState extends State<MyHomePage> {
                   );
                 },
               ),*/
-              RaisedButton(
-                child: Text('Add Chip'),
+              ElevatedButton(
                 onPressed: () {
-                  _chipKey.currentState.selectSuggestion(AppProfile(
+                  _chipKey.currentState?.selectSuggestion(AppProfile(
                       'Gina',
                       'fred@flutter.io',
                       'https://upload.wikimedia.org/wikipedia/commons/7/7c/Profile_avatar_placeholder_large.png'));
                 },
+                child: Text('Add Chip'),
               ),
             ],
           ),
diff --git a/example/pubspec.yaml b/example/pubspec.yaml
index 3aa75963..7a0e0a8f 100644
--- a/example/pubspec.yaml
+++ b/example/pubspec.yaml
@@ -2,7 +2,7 @@ name: example
 description: Example Project for flutter_chips_input
 
 environment:
-  sdk: ">=2.10.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
   flutter: ">=1.22.0"
 
 dependencies:
diff --git a/lib/src/chips_input.dart b/lib/src/chips_input.dart
index cfc00661..b2460d87 100644
--- a/lib/src/chips_input.dart
+++ b/lib/src/chips_input.dart
@@ -28,14 +28,14 @@ extension on TextEditingValue {
 
 class ChipsInput<T> extends StatefulWidget {
   const ChipsInput({
-    Key key,
+    Key? key,
     this.initialValue = const [],
     this.decoration = const InputDecoration(),
     this.enabled = true,
-    @required this.chipBuilder,
-    @required this.suggestionBuilder,
-    @required this.findSuggestions,
-    @required this.onChanged,
+    required this.chipBuilder,
+    required this.suggestionBuilder,
+    required this.findSuggestions,
+    required this.onChanged,
     this.onChipTapped,
     this.maxChips,
     this.textStyle,
@@ -56,28 +56,28 @@ class ChipsInput<T> extends StatefulWidget {
         super(key: key);
 
   final InputDecoration decoration;
-  final TextStyle textStyle;
+  final TextStyle? textStyle;
   final bool enabled;
   final ChipsInputSuggestions<T> findSuggestions;
   final ValueChanged<List<T>> onChanged;
   @Deprecated('Will be removed in the next major version')
-  final ValueChanged<T> onChipTapped;
+  final ValueChanged<T>? onChipTapped;
   final ChipsBuilder<T> chipBuilder;
   final ChipsBuilder<T> suggestionBuilder;
   final List<T> initialValue;
-  final int maxChips;
-  final double suggestionsBoxMaxHeight;
+  final int? maxChips;
+  final double? suggestionsBoxMaxHeight;
   final TextInputType inputType;
   final TextOverflow textOverflow;
   final bool obscureText;
   final bool autocorrect;
-  final String actionLabel;
+  final String? actionLabel;
   final TextInputAction inputAction;
   final Brightness keyboardAppearance;
   final bool autofocus;
   final bool allowChipEditing;
-  final FocusNode focusNode;
-  final List<T> initialSuggestions;
+  final FocusNode? focusNode;
+  final List<T>? initialSuggestions;
 
   // final Color cursorColor;
 
@@ -90,13 +90,14 @@ class ChipsInput<T> extends StatefulWidget {
 class ChipsInputState<T> extends State<ChipsInput<T>>
     implements TextInputClient {
   Set<T> _chips = <T>{};
-  List<T> _suggestions;
-  final _suggestionsStreamController = StreamController<List<T>>.broadcast();
+  List<T>? _suggestions;
+  final _suggestionsStreamController = StreamController<List<T>?>.broadcast();
   int _searchId = 0;
   TextEditingValue _value = TextEditingValue();
+
   // TextEditingValue _receivedRemoteTextEditingValue;
-  TextInputConnection _textInputConnection;
-  SuggestionsBoxController _suggestionsBoxController;
+  TextInputConnection? _textInputConnection;
+  SuggestionsBoxController? _suggestionsBoxController;
   final _layerLink = LayerLink();
   final _enteredTexts = <T, String>{};
 
@@ -111,33 +112,42 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
       );
 
   bool get _hasInputConnection =>
-      _textInputConnection != null && _textInputConnection.attached;
+      _textInputConnection != null && _textInputConnection!.attached;
 
   bool get _hasReachedMaxChips =>
-      widget.maxChips != null && _chips.length >= widget.maxChips;
+      widget.maxChips != null && _chips.length >= widget.maxChips!;
 
   // FocusAttachment _focusAttachment;
-  FocusNode _focusNode;
-
-  RenderBox get renderBox => context.findRenderObject();
+  FocusNode? _focusNode;
 
   @override
   void initState() {
     super.initState();
     _chips.addAll(widget.initialValue);
+    final initialText =
+        String.fromCharCodes(_chips.map((_) => kObjectReplacementChar));
+    _value = TextEditingValue(
+      text: initialText,
+      selection: TextSelection.collapsed(offset: initialText.length),
+    );
+
     _suggestions = widget.initialSuggestions
         ?.where((r) => !_chips.contains(r))
-        ?.toList(growable: false);
+        .toList(growable: false);
     // _focusAttachment = _focusNode.attach(context);
     _suggestionsBoxController = SuggestionsBoxController(context);
 
     _focusNode = widget.focusNode ?? FocusNode();
-    _focusNode.addListener(_handleFocusChanged);
+    _focusNode!.addListener(_handleFocusChanged);
 
-    WidgetsBinding.instance.addPostFrameCallback((_) async {
-      _initOverlayEntry();
+    WidgetsBinding.instance?.addPostFrameCallback((_) async {
+      final renderBox = context.findRenderObject() as RenderBox?;
+      assert(renderBox != null,
+          "This cannot be null because it's called after the build");
+
+      _initOverlayEntry(renderBox!);
       if (mounted && widget.autofocus && _focusNode != null) {
-        FocusScope.of(context).autofocus(_focusNode);
+        FocusScope.of(context).autofocus(_focusNode!);
       }
     });
   }
@@ -146,13 +156,13 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
   void dispose() {
     _closeInputConnectionIfNeeded();
 
-    _focusNode.removeListener(_handleFocusChanged);
+    _focusNode?.removeListener(_handleFocusChanged);
     if (null == widget.focusNode) {
-      _focusNode.dispose();
+      _focusNode?.dispose();
     }
 
     _suggestionsStreamController.close();
-    _suggestionsBoxController.close();
+    _suggestionsBoxController?.close();
     super.dispose();
   }
 
@@ -163,12 +173,12 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
   }
 
   void _handleFocusChanged() {
-    if (_focusNode.hasFocus) {
+    if (_focusNode != null && _focusNode!.hasFocus) {
       _openInputConnection();
-      _suggestionsBoxController.open();
+      _suggestionsBoxController?.open();
     } else {
       _closeInputConnectionIfNeeded();
-      _suggestionsBoxController.close();
+      _suggestionsBoxController?.close();
     }
     if (mounted) {
       setState(() {
@@ -177,9 +187,9 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
     }
   }
 
-  void _initOverlayEntry() {
+  void _initOverlayEntry(RenderBox renderBox) {
     // _suggestionsBoxController.close();
-    _suggestionsBoxController.overlayEntry = OverlayEntry(
+    _suggestionsBoxController?.overlayEntry = OverlayEntry(
       builder: (context) {
         final size = renderBox.size;
         final renderBoxOffset = renderBox.localToGlobal(Offset.zero);
@@ -190,20 +200,20 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
             renderBoxOffset.dy -
             size.height;
         var _suggestionBoxHeight = max(topAvailableSpace, bottomAvailableSpace);
-        if (null != widget.suggestionsBoxMaxHeight) {
+        if (widget.suggestionsBoxMaxHeight != null) {
           _suggestionBoxHeight =
-              min(_suggestionBoxHeight, widget.suggestionsBoxMaxHeight);
+              min(_suggestionBoxHeight, widget.suggestionsBoxMaxHeight!);
         }
         final showTop = topAvailableSpace > bottomAvailableSpace;
         // print("showTop: $showTop" );
         final compositedTransformFollowerOffset =
             showTop ? Offset(0, -size.height) : Offset.zero;
 
-        return StreamBuilder<List<T>>(
+        return StreamBuilder<List<T>?>(
           stream: _suggestionsStreamController.stream,
           initialData: _suggestions,
           builder: (context, snapshot) {
-            if (snapshot.hasData && snapshot.data.isNotEmpty) {
+            if (snapshot.hasData && (snapshot.data ?? []).isNotEmpty) {
               var suggestionsListView = Material(
                 elevation: 4.0,
                 child: ConstrainedBox(
@@ -213,12 +223,13 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
                   child: ListView.builder(
                     shrinkWrap: true,
                     padding: EdgeInsets.zero,
-                    itemCount: snapshot.data.length,
+                    itemCount:
+                        snapshot.data == null ? 0 : snapshot.data!.length,
                     itemBuilder: (BuildContext context, int index) {
                       return widget.suggestionBuilder(
                         context,
                         this,
-                        _suggestions[index],
+                        snapshot.data![index],
                       );
                     },
                   ),
@@ -250,16 +261,16 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
     if (!_hasReachedMaxChips) {
       _chips.add(data);
       if (widget.allowChipEditing) {
-        var enteredText = _value.normalCharactersText ?? '';
+        var enteredText = _value.normalCharactersText;
         if (enteredText.isNotEmpty) _enteredTexts[data] = enteredText;
       }
       _updateTextInputState(replaceText: true);
 
       _suggestions = null;
       _suggestionsStreamController.add(_suggestions);
-      if (widget.maxChips == _chips.length) _suggestionsBoxController.close();
+      if (widget.maxChips == _chips.length) _suggestionsBoxController?.close();
     } else {
-      _suggestionsBoxController.close();
+      _suggestionsBoxController?.close();
     }
     widget.onChanged(_chips.toList(growable: false));
   }
@@ -278,12 +289,14 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
       _textInputConnection = TextInput.attach(this, textInputConfiguration)
         ..setEditingState(_value);
     }
-    _textInputConnection.show();
+    _textInputConnection?.show();
 
     Future.delayed(const Duration(milliseconds: 100), () {
-      WidgetsBinding.instance.addPostFrameCallback((_) async {
-        final RenderBox renderBox = context.findRenderObject();
-        await Scrollable.of(context)?.position?.ensureVisible(renderBox);
+      WidgetsBinding.instance?.addPostFrameCallback((_) async {
+        final renderBox = context.findRenderObject();
+        if (renderBox != null) {
+          await Scrollable.of(context)?.position.ensureVisible(renderBox);
+        }
       });
     });
   }
@@ -300,7 +313,7 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
 
   void _closeInputConnectionIfNeeded() {
     if (_hasInputConnection) {
-      _textInputConnection.close();
+      _textInputConnection?.close();
       _textInputConnection = null;
       // _receivedRemoteTextEditingValue = null;
     }
@@ -320,7 +333,7 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
         var removedChip = _chips.last;
         _chips = Set.of(_chips.take(value.replacementCharactersCount));
         widget.onChanged(_chips.toList(growable: false));
-        var putText = '';
+        String? putText = '';
         if (widget.allowChipEditing && _enteredTexts.containsKey(removedChip)) {
           putText = _enteredTexts[removedChip];
           _enteredTexts.remove(removedChip);
@@ -345,9 +358,8 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
         //composing: TextRange(start: 0, end: text.length),
       );
     });
-    _closeInputConnectionIfNeeded(); //Hack for #34 (https://github.com/danvick/flutter_chips_input/issues/34#issuecomment-684505282). TODO: Find permanent fix
     _textInputConnection ??= TextInput.attach(this, textInputConfiguration);
-    _textInputConnection.setEditingState(_value);
+    _textInputConnection?.setEditingState(_value);
     // _closeInputConnectionIfNeeded(false);
   }
 
@@ -358,14 +370,14 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
       case TextInputAction.go:
       case TextInputAction.send:
       case TextInputAction.search:
-        if (_suggestions != null && _suggestions.isNotEmpty) {
-          selectSuggestion(_suggestions.first);
+        if (_suggestions != null && _suggestions!.isNotEmpty) {
+          selectSuggestion(_suggestions!.first);
         } else {
-          _focusNode.unfocus();
+          _focusNode?.unfocus();
         }
         break;
       default:
-        _focusNode.unfocus();
+        _focusNode?.unfocus();
         break;
     }
   }
@@ -376,7 +388,7 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
   }
 
   @override
-  void didUpdateWidget(ChipsInput oldWidget) {
+  void didUpdateWidget(ChipsInput<T> oldWidget) {
     super.didUpdateWidget(oldWidget);
     /* if(widget.focusNode != oldWidget.focusNode){
       oldWidget.focusNode.removeListener(_handleFocusChanged);
@@ -403,7 +415,7 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
   void showAutocorrectionPromptRect(int start, int end) {}
 
   @override
-  AutofillScope get currentAutofillScope => null;
+  AutofillScope? get currentAutofillScope => null;
 
   @override
   Widget build(BuildContext context) {
@@ -427,12 +439,13 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
                 maxLines: 1,
                 overflow: widget.textOverflow,
                 style: widget.textStyle ??
-                    theme.textTheme.subtitle1.copyWith(height: 1.5),
+                    theme.textTheme.subtitle1?.copyWith(height: 1.5),
               ),
             ),
             Flexible(
               flex: 0,
-              child: TextCursor(resumed: _focusNode.hasFocus),
+              child: TextCursor(
+                  resumed: _focusNode != null && _focusNode!.hasFocus),
             ),
           ],
         ),
@@ -441,8 +454,8 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
 
     return NotificationListener<SizeChangedLayoutNotification>(
       onNotification: (SizeChangedLayoutNotification val) {
-        WidgetsBinding.instance.addPostFrameCallback((_) async {
-          _suggestionsBoxController.overlayEntry.markNeedsBuild();
+        WidgetsBinding.instance?.addPostFrameCallback((_) async {
+          _suggestionsBoxController?.overlayEntry?.markNeedsBuild();
         });
         return true;
       },
@@ -457,12 +470,12 @@ class ChipsInputState<T> extends State<ChipsInput<T>>
               },
               child: InputDecorator(
                 decoration: widget.decoration,
-                isFocused: _focusNode.hasFocus,
+                isFocused: _focusNode != null && _focusNode!.hasFocus,
                 isEmpty: _value.text.isEmpty && _chips.isEmpty,
                 child: Wrap(
-                  children: chipsChildren,
                   spacing: 4.0,
                   runSpacing: 4.0,
+                  children: chipsChildren,
                 ),
               ),
             ),
diff --git a/lib/src/suggestions_box_controller.dart b/lib/src/suggestions_box_controller.dart
index 5fbf4baf..df9586e0 100644
--- a/lib/src/suggestions_box_controller.dart
+++ b/lib/src/suggestions_box_controller.dart
@@ -3,7 +3,7 @@ import 'package:flutter/material.dart';
 class SuggestionsBoxController {
   final BuildContext context;
 
-  OverlayEntry overlayEntry;
+  OverlayEntry? overlayEntry;
 
   bool _isOpened = false;
 
@@ -14,7 +14,7 @@ class SuggestionsBoxController {
   void open() {
     if (_isOpened) return;
     assert(overlayEntry != null);
-    Overlay.of(context).insert(overlayEntry);
+    Overlay.of(context)?.insert(overlayEntry!);
     _isOpened = true;
   }
 
@@ -22,7 +22,7 @@ class SuggestionsBoxController {
     // debugPrint("Closing suggestion box");
     if (!_isOpened) return;
     assert(overlayEntry != null);
-    overlayEntry.remove();
+    overlayEntry!.remove();
     _isOpened = false;
   }
 
diff --git a/lib/src/text_cursor.dart b/lib/src/text_cursor.dart
index 3a9118e2..cd08fb32 100644
--- a/lib/src/text_cursor.dart
+++ b/lib/src/text_cursor.dart
@@ -4,7 +4,7 @@ import 'package:flutter/material.dart';
 
 class TextCursor extends StatefulWidget {
   const TextCursor({
-    Key key,
+    Key? key,
     this.duration = const Duration(milliseconds: 500),
     this.resumed = false,
   }) : super(key: key);
@@ -19,7 +19,7 @@ class TextCursor extends StatefulWidget {
 class _TextCursorState extends State<TextCursor>
     with SingleTickerProviderStateMixin {
   bool _displayed = false;
-  Timer _timer;
+  Timer? _timer;
 
   @override
   void initState() {
@@ -33,7 +33,7 @@ class _TextCursorState extends State<TextCursor>
 
   @override
   void dispose() {
-    _timer.cancel();
+    _timer?.cancel();
     super.dispose();
   }
 
diff --git a/pubspec.yaml b/pubspec.yaml
index fc372cb1..dfe6da32 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -4,7 +4,7 @@ version: 1.10.0
 homepage: https://github.com/danvick/flutter_chips_input
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   flutter: