update dart and flutter version

example/lib/highlight.dart

@@ -6,7 +6,6 @@
  * @LastEditTime: 2020-08-02 12:39:26
  */
 import 'dart:math';
-import 'dart:ui';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_highlight/themes/a11y-light.dart';
@@ -30,16 +29,16 @@ List<TextSpan> _convert(String code) {
       stack.add(currentSpans);
       currentSpans = tmp;
 
-      node.children.forEach((n) {
+      node.children!.forEach((n) {
         _traverse(n);
-        if (n == node.children.last) {
+        if (n == node.children!.last) {
           currentSpans = stack.isEmpty ? spans : stack.removeLast();
         }
       });
     }
   }
 
-  for (var node in nodes) {
+  for (var node in nodes!) {
     _traverse(node);
   }
 
@@ -47,18 +46,19 @@ List<TextSpan> _convert(String code) {
 }
 
 class CodeInputController extends TextEditingController {
-  CodeInputController({String text}) : super(text: text);
+  CodeInputController({required String text}) : super(text: text);
 
   TextSpan oldSpan = TextSpan();
-  Future<void> spanCall;
+  Future<void>? spanCall;
 
   @override
   TextSpan buildTextSpan(
-      {@required BuildContext context, TextStyle style, bool withComposing}) {
+      {required BuildContext context, TextStyle? style,
+        bool? withComposing}) {
     String oldText = oldSpan.toPlainText();
     String newText = value.text;
     if (oldText == newText) return oldSpan;
-    (spanCall?.timeout(Duration.zero) ?? Future.value())
+    spanCall?.timeout(Duration.zero)
         .then((_) => spanCall = compute(_convert, value.text).then((lsSpan) {
               TextSpan newSpan = TextSpan(style: style, children: lsSpan);
               if (newSpan.toPlainText() == value.text) oldSpan = newSpan;
@@ -70,7 +70,7 @@ class CodeInputController extends TextEditingController {
     int splitAt = value.selection.start;
     if (splitAt < 0) splitAt = newText.length ~/ 2;
     int start = 0;
-    InlineSpan leftSpan;
+    InlineSpan? leftSpan;
     oldSpan.children?.indexWhere((element) {
       String elementText = element.toPlainText();
       if (start + elementText.length > splitAt ||
@@ -78,14 +78,14 @@ class CodeInputController extends TextEditingController {
         leftSpan = element;
         return true;
       }
-      beforeSpans.add(element);
+      beforeSpans.add(element as TextSpan);
       start += elementText.length;
       return false;
     });
     List<TextSpan> endSpans = [];
     int end = 0;
-    InlineSpan rightSpan;
-    oldSpan.children?.sublist(beforeSpans.length)?.lastIndexWhere((element) {
+    InlineSpan? rightSpan;
+    oldSpan.children?.sublist(beforeSpans.length).lastIndexWhere((element) {
       String elementText = element.toPlainText();
       if (splitAt + end + elementText.length >= newText.length ||
           !newText
@@ -94,7 +94,7 @@ class CodeInputController extends TextEditingController {
         rightSpan = element;
         return true;
       }
-      endSpans.add(element);
+      endSpans.add(element as TextSpan);
       end += elementText.length;
       return false;
     });
@@ -102,8 +102,8 @@ class CodeInputController extends TextEditingController {
     return TextSpan(style: style, children: [
       ...beforeSpans,
       TextSpan(
-          style: leftSpan != null && leftSpan == rightSpan
-              ? leftSpan.style
+          style: leftSpan != null && leftSpan == rightSpan!
+              ? leftSpan!.style
               : style,
           text: newText.substring(start, max(start, newText.length - end))),
       ...endSpans.reversed

example/lib/main.dart

@@ -17,7 +17,7 @@ void main() {
 }
 
 class MyApp extends StatelessWidget {
-  const MyApp({Key key}) : super(key: key);
+  const MyApp({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -25,9 +25,9 @@ class MyApp extends StatelessWidget {
       title: 'flutter_qjs',
       debugShowCheckedModeBanner: false,
       theme: ThemeData(
-        appBarTheme: AppBarTheme(brightness: Brightness.dark, elevation: 0),
-        backgroundColor: Colors.grey[300],
-        primaryColorBrightness: Brightness.dark,
+        brightness: Brightness.dark,
+        colorScheme: ColorScheme.fromSeed(seedColor: Colors.blue, brightness: Brightness.dark),
+        useMaterial3: true
       ),
       routes: {
         'home': (BuildContext context) => TestPage(),
@@ -43,8 +43,8 @@ class TestPage extends StatefulWidget {
 }
 
 class _TestPageState extends State<TestPage> {
-  String resp;
-  IsolateQjs engine;
+  String? resp;
+  IsolateQjs? engine;
 
   CodeInputController _controller = CodeInputController(
       text: 'import("hello").then(({default: greet}) => greet("world"));');
@@ -79,7 +79,7 @@ class _TestPageState extends State<TestPage> {
                       onPressed: () async {
                         await _ensureEngine();
                         try {
-                          resp = (await engine.evaluate(_controller.text ?? '',
+                          resp = (await engine!.evaluate(_controller.text,
                                   name: "<eval>"))
                               .toString();
                         } catch (e) {
@@ -91,7 +91,7 @@ class _TestPageState extends State<TestPage> {
                       child: Text("reset engine"),
                       onPressed: () async {
                         if (engine == null) return;
-                        await engine.close();
+                        await engine!.close();
                         engine = null;
                       }),
                 ],