diff --git a/.gitignore b/.gitignore
index 979ee4c..be151c9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,6 +9,7 @@
 .buildlog/
 .history
 .svn/
+.vscode/
 
 # IntelliJ related
 *.iml
@@ -29,6 +30,7 @@
 .pub-cache/
 .pub/
 build/
+pubspec.lock
 
 # Android related
 **/android/**/gradle-wrapper.jar
@@ -71,3 +73,5 @@ build/
 !**/ios/**/default.pbxuser
 !**/ios/**/default.perspectivev3
 !/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
+example/.gitignore
+example/pubspec.lock
diff --git a/example/.gitignore b/example/.gitignore
index 7391f94..a8eb59a 100644
--- a/example/.gitignore
+++ b/example/.gitignore
@@ -13,6 +13,8 @@
 **/android/
 **/ios/
 **/macos/
+**/windows/
+**/web/
 
 # IntelliJ related
 *.iml
diff --git a/example/lib/example.dart b/example/lib/example.dart
deleted file mode 100644
index 93e40ab..0000000
--- a/example/lib/example.dart
+++ /dev/null
@@ -1,12 +0,0 @@
-import 'package:flutter/material.dart';
-
-class Example extends StatelessWidget {
-  const Example({Key key}) : super(key: key);
-
-  @override
-  Widget build(BuildContext context) {
-    return Container(
-      child: Text("An example widget"),
-    );
-  }
-}
diff --git a/example/lib/main.dart b/example/lib/main.dart
index d6da513..9a980a0 100644
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -1,45 +1,73 @@
+import 'dart:math';
+
 import 'package:flutter/material.dart';
 import 'package:widget_with_codeview/widget_with_codeview.dart';
 
-import 'example.dart';
-
 void main() {
   runApp(MyApp());
 }
 
+/// ensure the files in sourceFilePath are included in pubspec.yaml
+/// in this case the codeViewer will display this file's code
+/// by pointing to the main.dart file
 class MyApp extends StatelessWidget {
-  // This widget is the root of your application.
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
-      title: 'Flutter Demo',
-      theme: ThemeData(
-        primarySwatch: Colors.blue,
+      theme: ThemeData.dark(),
+      home: Scaffold(
+        body: WidgetWithCodeView(
+          child: const SomeWidget(),
+          sourceFilePath: 'lib/main.dart',
+          codeLinkPrefix: 'https://google.com?q=',
+          iconBackgroundColor: Colors.white,
+          iconForegroundColor: Colors.pink,
+          labelBackgroundColor: Theme.of(context).canvasColor,
+          labelTextStyle:
+              TextStyle(color: Theme.of(context).textTheme.bodyText1.color),
+          showLabelText: true,
+          syntaxHighlighterStyle:
+              SyntaxHighlighterStyle.darkThemeStyle().copyWith(
+            commentStyle: TextStyle(color: Colors.yellow),
+            keywordStyle: TextStyle(color: Colors.lightGreen),
+            classStyle: TextStyle(color: Colors.amber),
+            numberStyle: TextStyle(color: Colors.orange),
+          ),
+        ),
       ),
-      home: MyHomePage(title: 'Flutter Demo Home Page'),
     );
   }
 }
 
-class MyHomePage extends StatefulWidget {
-  MyHomePage({Key key, this.title}) : super(key: key);
-  final String title;
-
-  @override
-  _MyHomePageState createState() => _MyHomePageState();
-}
+class SomeWidget extends StatelessWidget {
+  const SomeWidget({Key key}) : super(key: key);
 
-class _MyHomePageState extends State<MyHomePage> {
   @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-      appBar: AppBar(
-        title: Text(widget.title),
-      ),
-      body: WidgetWithCodeView(
-        child: Example(),
-        sourceFilePath: 'lib/example.dart',
-      ),
-    );
-  }
+  Widget build(BuildContext context) => Stack(
+        children: [
+          Center(
+            child: Transform.rotate(
+              angle: Random().nextDouble(),
+              child: Text(
+                'Example',
+                textScaleFactor: 2,
+              ),
+            ),
+          ),
+          Wrap(
+            children: List.generate(
+              100,
+              (_) => SizedBox(
+                width: MediaQuery.of(context).size.width * .25,
+                height: MediaQuery.of(context).size.width * .25,
+                child: Placeholder(
+                  color: Colors.accents[Random().nextInt(
+                    Colors.accents.length,
+                  )],
+                ),
+              ),
+            ),
+          ),
+        ],
+      );
 }
diff --git a/example/pubspec.lock b/example/pubspec.lock
index a346624..aa4a460 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -7,7 +7,7 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.5.0"
+    version: "2.6.1"
   boolean_selector:
     dependency: transitive
     description:
@@ -223,7 +223,7 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0"
+    version: "1.8.1"
   stack_trace:
     dependency: transitive
     description:
@@ -258,7 +258,7 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.19"
+    version: "0.3.0"
   typed_data:
     dependency: transitive
     description:
diff --git a/example/pubspec.yaml b/example/pubspec.yaml
index 7186841..f511aa9 100644
--- a/example/pubspec.yaml
+++ b/example/pubspec.yaml
@@ -30,4 +30,4 @@ flutter:
   uses-material-design: true
 
   assets:
-    - lib/example.dart
+    - lib/
diff --git a/example/test/widget_test.dart b/example/test/widget_test.dart
index 2a37b68..be797e7 100644
--- a/example/test/widget_test.dart
+++ b/example/test/widget_test.dart
@@ -5,15 +5,14 @@
 // gestures. You can also use WidgetTester to find child widgets in the widget
 // tree, read text, and verify that the values of widget properties are correct.
 
-import 'package:example/main.dart';
-import 'package:flutter/material.dart';
-import 'package:flutter_test/flutter_test.dart';
+// import 'package:example/main.dart';
+// import 'package:flutter_test/flutter_test.dart';
 
 void main() {
-  testWidgets('smoke test', (WidgetTester tester) async {
-    // Build our app and trigger a frame.
-    await tester.pumpWidget(MyApp());
+  // testWidgets('smoke test', (WidgetTester tester) async {
+  //   // Build our app and trigger a frame.
+  //   // await tester.pumpWidget(MyApp());
 
-    expect(find.text('1'), findsNothing);
-  });
+  //   // expect(find.text('1'), findsNothing);
+  // });
 }
diff --git a/lib/source_code_view.dart b/lib/source_code_view.dart
deleted file mode 100644
index 2de8433..0000000
--- a/lib/source_code_view.dart
+++ /dev/null
@@ -1,133 +0,0 @@
-import 'dart:math';
-
-import 'package:flutter/material.dart';
-import 'package:flutter/services.dart';
-import 'package:flutter_speed_dial/flutter_speed_dial.dart';
-import 'package:google_fonts/google_fonts.dart';
-import 'package:url_launcher/url_launcher.dart' as url_launcher;
-import 'syntax_highlighter.dart';
-
-class SourceCodeView extends StatefulWidget {
-  final String filePath;
-  final String? codeLinkPrefix;
-
-  const SourceCodeView({Key? key, required this.filePath, this.codeLinkPrefix})
-      : super(key: key);
-
-  String? get codeLink => this.codeLinkPrefix == null
-      ? null
-      : '${this.codeLinkPrefix}/${this.filePath}';
-
-  @override
-  _SourceCodeViewState createState() {
-    return _SourceCodeViewState();
-  }
-}
-
-class _SourceCodeViewState extends State<SourceCodeView> {
-  double _textScaleFactor = 1.0;
-
-  Widget _getCodeView(String codeContent, BuildContext context) {
-    codeContent = codeContent.replaceAll('\r\n', '\n');
-    final SyntaxHighlighterStyle style =
-        Theme.of(context).brightness == Brightness.dark
-            ? SyntaxHighlighterStyle.darkThemeStyle()
-            : SyntaxHighlighterStyle.lightThemeStyle();
-    return Container(
-      constraints: BoxConstraints.expand(),
-      child: Scrollbar(
-        child: SingleChildScrollView(
-          child: SingleChildScrollView(
-            scrollDirection: Axis.horizontal,
-            child: SelectableText.rich(
-              TextSpan(
-                style: GoogleFonts.droidSansMono(fontSize: 12)
-                    .apply(fontSizeFactor: this._textScaleFactor),
-                children: <TextSpan>[
-                  DartSyntaxHighlighter(style).format(codeContent)
-                ],
-              ),
-              style: DefaultTextStyle.of(context)
-                  .style
-                  .apply(fontSizeFactor: this._textScaleFactor),
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-
-  List<SpeedDialChild> _buildFloatingButtons() {
-    return <SpeedDialChild>[
-      if (this.widget.codeLink != null)
-        SpeedDialChild(
-          child: Icon(Icons.content_copy),
-          label: 'Copy code link to clipboard',
-          backgroundColor: Colors.blue,
-          foregroundColor: Colors.white,
-          onTap: () {
-            Clipboard.setData(ClipboardData(text: this.widget.codeLink));
-            ScaffoldMessenger.of(context).showSnackBar(SnackBar(
-              content: Text('Code link copied to clipboard!'),
-            ));
-          },
-        ),
-      if (this.widget.codeLink != null)
-        SpeedDialChild(
-          child: Icon(Icons.open_in_new),
-          label: 'View code in browser',
-          backgroundColor: Colors.blue,
-          foregroundColor: Colors.white,
-          onTap: () => url_launcher.launch(this.widget.codeLink!),
-        ),
-      SpeedDialChild(
-        child: Icon(Icons.zoom_out),
-        label: 'Zoom out',
-        backgroundColor: Colors.blue,
-        foregroundColor: Colors.white,
-        onTap: () => setState(() {
-          this._textScaleFactor = max(0.8, this._textScaleFactor - 0.1);
-        }),
-      ),
-      SpeedDialChild(
-        child: Icon(Icons.zoom_in),
-        label: 'Zoom in',
-        backgroundColor: Colors.blue,
-        foregroundColor: Colors.white,
-        onTap: () => setState(() {
-          this._textScaleFactor += 0.1;
-        }),
-      ),
-    ];
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return FutureBuilder(
-      future: DefaultAssetBundle.of(context).loadString(widget.filePath),
-      builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
-        if (snapshot.hasData) {
-          return Scaffold(
-            body: Padding(
-              padding: EdgeInsets.all(4.0),
-              child: _getCodeView(snapshot.data!, context),
-            ),
-            floatingActionButton: SpeedDial(
-              renderOverlay: false,
-              overlayOpacity: 0,
-              children: _buildFloatingButtons(),
-              backgroundColor: Colors.blue,
-              foregroundColor: Colors.white,
-              activeBackgroundColor: Colors.red,
-              activeForegroundColor: Colors.white,
-              icon: Icons.menu,
-              activeIcon: Icons.close,
-            ),
-          );
-        } else {
-          return Center(child: CircularProgressIndicator());
-        }
-      },
-    );
-  }
-}
diff --git a/lib/src/source_code_view.dart b/lib/src/source_code_view.dart
new file mode 100644
index 0000000..8602f1d
--- /dev/null
+++ b/lib/src/source_code_view.dart
@@ -0,0 +1,169 @@
+import 'dart:math';
+
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_speed_dial/flutter_speed_dial.dart';
+import 'package:google_fonts/google_fonts.dart';
+import 'package:url_launcher/url_launcher.dart' as url_launcher;
+import 'syntax_highlighter.dart';
+
+class SourceCodeView extends StatefulWidget {
+  final String filePath;
+  final String? codeLinkPrefix;
+  final bool showLabelText;
+  final Color? iconBackgroundColor;
+  final Color? iconForegroundColor;
+  final Color? labelBackgroundColor;
+  final TextStyle? labelTextStyle;
+  final SyntaxHighlighterStyle? syntaxHighlighterStyle;
+
+  const SourceCodeView({
+    Key? key,
+    required this.filePath,
+    this.codeLinkPrefix,
+    this.showLabelText = false,
+    this.iconBackgroundColor,
+    this.iconForegroundColor,
+    this.labelBackgroundColor,
+    this.labelTextStyle,
+    this.syntaxHighlighterStyle,
+  }) : super(key: key);
+
+  String? get codeLink => this.codeLinkPrefix == null
+      ? null
+      : '${this.codeLinkPrefix}/${this.filePath}';
+
+  @override
+  _SourceCodeViewState createState() {
+    return _SourceCodeViewState();
+  }
+}
+
+class _SourceCodeViewState extends State<SourceCodeView> {
+  double _textScaleFactor = 1.0;
+
+  Widget _getCodeView(String codeContent, BuildContext context) {
+    codeContent = codeContent.replaceAll('\r\n', '\n');
+    final SyntaxHighlighterStyle style = widget.syntaxHighlighterStyle ??
+        (Theme.of(context).brightness == Brightness.dark
+            ? SyntaxHighlighterStyle.darkThemeStyle()
+            : SyntaxHighlighterStyle.lightThemeStyle());
+    return Container(
+      constraints: BoxConstraints.expand(),
+      child: Scrollbar(
+        child: SingleChildScrollView(
+          child: SingleChildScrollView(
+            scrollDirection: Axis.horizontal,
+            child: SelectableText.rich(
+              TextSpan(
+                style: GoogleFonts.droidSansMono(fontSize: 12)
+                    .apply(fontSizeFactor: this._textScaleFactor),
+                children: <TextSpan>[
+                  DartSyntaxHighlighter(style).format(codeContent)
+                ],
+              ),
+              style: DefaultTextStyle.of(context)
+                  .style
+                  .apply(fontSizeFactor: this._textScaleFactor),
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+
+  List<SpeedDialChild> _buildFloatingButtons({
+    TextStyle? labelTextStyle,
+    Color? iconBackgroundColor,
+    Color? iconForegroundColor,
+    Color? labelBackgroundColor,
+    required bool showLabelText,
+  }) =>
+      [
+        if (this.widget.codeLink != null)
+          SpeedDialChild(
+            child: Icon(Icons.content_copy),
+            label: showLabelText ? 'Copy code to clipboard' : null,
+            backgroundColor: iconBackgroundColor,
+            foregroundColor: iconForegroundColor,
+            labelBackgroundColor: labelBackgroundColor,
+            labelStyle: labelTextStyle,
+            onTap: () async {
+              Clipboard.setData(ClipboardData(
+                  text: await DefaultAssetBundle.of(context)
+                      .loadString(widget.filePath)));
+              ScaffoldMessenger.of(context).showSnackBar(SnackBar(
+                content: Text('Code copied to clipboard!'),
+              ));
+            },
+          ),
+        if (this.widget.codeLink != null)
+          SpeedDialChild(
+            child: Icon(Icons.open_in_new),
+            label: showLabelText ? 'View code in browser' : null,
+            backgroundColor: iconBackgroundColor,
+            foregroundColor: iconForegroundColor,
+            labelBackgroundColor: labelBackgroundColor,
+            labelStyle: labelTextStyle,
+            onTap: () => url_launcher.launch(this.widget.codeLink!),
+          ),
+        SpeedDialChild(
+          child: Icon(Icons.zoom_out),
+          label: showLabelText ? 'Zoom out' : null,
+          backgroundColor: iconBackgroundColor,
+          foregroundColor: iconForegroundColor,
+          labelBackgroundColor: labelBackgroundColor,
+          labelStyle: labelTextStyle,
+          onTap: () => setState(() {
+            this._textScaleFactor = max(0.8, this._textScaleFactor - 0.1);
+          }),
+        ),
+        SpeedDialChild(
+          child: Icon(Icons.zoom_in),
+          label: showLabelText ? 'Zoom in' : null,
+          backgroundColor: iconBackgroundColor,
+          foregroundColor: iconForegroundColor,
+          labelBackgroundColor: labelBackgroundColor,
+          labelStyle: labelTextStyle,
+          onTap: () => setState(() {
+            this._textScaleFactor += 0.1;
+          }),
+        ),
+      ];
+
+  @override
+  Widget build(BuildContext context) {
+    return FutureBuilder(
+      future: DefaultAssetBundle.of(context).loadString(widget.filePath),
+      builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
+        if (snapshot.hasData) {
+          return Scaffold(
+            body: Padding(
+              padding: EdgeInsets.all(4.0),
+              child: _getCodeView(snapshot.data!, context),
+            ),
+            floatingActionButton: SpeedDial(
+              renderOverlay: false,
+              overlayOpacity: 0,
+              children: _buildFloatingButtons(
+                labelTextStyle: widget.labelTextStyle,
+                iconBackgroundColor: widget.iconBackgroundColor,
+                iconForegroundColor: widget.iconForegroundColor,
+                labelBackgroundColor: widget.labelBackgroundColor,
+                showLabelText: widget.showLabelText,
+              ),
+              backgroundColor: Colors.blue,
+              foregroundColor: Colors.white,
+              activeBackgroundColor: Colors.red,
+              activeForegroundColor: Colors.white,
+              icon: Icons.menu,
+              activeIcon: Icons.close,
+            ),
+          );
+        } else {
+          return Center(child: CircularProgressIndicator());
+        }
+      },
+    );
+  }
+}
diff --git a/lib/syntax_highlighter.dart b/lib/src/syntax_highlighter.dart
similarity index 91%
rename from lib/syntax_highlighter.dart
rename to lib/src/syntax_highlighter.dart
index 88d2bee..b46e2ab 100644
--- a/lib/syntax_highlighter.dart
+++ b/lib/src/syntax_highlighter.dart
@@ -16,8 +16,7 @@ class SyntaxHighlighterStyle {
       this.classStyle,
       this.constantStyle});
 
-  static SyntaxHighlighterStyle lightThemeStyle() {
-    return SyntaxHighlighterStyle(
+  static SyntaxHighlighterStyle lightThemeStyle() => SyntaxHighlighterStyle(
         baseStyle: const TextStyle(color: const Color(0xFF000000)),
         numberStyle: const TextStyle(color: const Color(0xFF1565C0)),
         commentStyle: const TextStyle(color: const Color(0xFF9E9E9E)),
@@ -25,11 +24,10 @@ class SyntaxHighlighterStyle {
         stringStyle: const TextStyle(color: const Color(0xFF43A047)),
         punctuationStyle: const TextStyle(color: const Color(0xFF000000)),
         classStyle: const TextStyle(color: const Color(0xFF512DA8)),
-        constantStyle: const TextStyle(color: const Color(0xFF795548)));
-  }
+        constantStyle: const TextStyle(color: const Color(0xFF795548)),
+      );
 
-  static SyntaxHighlighterStyle darkThemeStyle() {
-    return SyntaxHighlighterStyle(
+  static SyntaxHighlighterStyle darkThemeStyle() => SyntaxHighlighterStyle(
         baseStyle: const TextStyle(color: const Color(0xFFFFFFFF)),
         numberStyle: const TextStyle(color: const Color(0xFF1565C0)),
         commentStyle: const TextStyle(color: const Color(0xFF9E9E9E)),
@@ -37,8 +35,29 @@ class SyntaxHighlighterStyle {
         stringStyle: const TextStyle(color: const Color(0xFF009688)),
         punctuationStyle: const TextStyle(color: const Color(0xFFFFFFFF)),
         classStyle: const TextStyle(color: const Color(0xFF009688)),
-        constantStyle: const TextStyle(color: const Color(0xFF795548)));
-  }
+        constantStyle: const TextStyle(color: const Color(0xFF795548)),
+      );
+
+  SyntaxHighlighterStyle copyWith({
+    TextStyle? baseStyle,
+    TextStyle? numberStyle,
+    TextStyle? commentStyle,
+    TextStyle? keywordStyle,
+    TextStyle? stringStyle,
+    TextStyle? punctuationStyle,
+    TextStyle? classStyle,
+    TextStyle? constantStyle,
+  }) =>
+      SyntaxHighlighterStyle(
+        baseStyle: baseStyle ?? this.baseStyle,
+        numberStyle: numberStyle ?? this.numberStyle,
+        commentStyle: commentStyle ?? this.commentStyle,
+        keywordStyle: keywordStyle ?? this.keywordStyle,
+        stringStyle: stringStyle ?? this.stringStyle,
+        punctuationStyle: punctuationStyle ?? this.punctuationStyle,
+        classStyle: classStyle ?? this.classStyle,
+        constantStyle: constantStyle ?? this.constantStyle,
+      );
 
   final TextStyle? baseStyle;
   final TextStyle? numberStyle;
diff --git a/lib/src/widget_with_codeview.dart b/lib/src/widget_with_codeview.dart
new file mode 100644
index 0000000..145073e
--- /dev/null
+++ b/lib/src/widget_with_codeview.dart
@@ -0,0 +1,142 @@
+library widget_with_codeview;
+
+import 'package:flutter/material.dart';
+
+import 'source_code_view.dart';
+import 'syntax_highlighter.dart';
+
+class WidgetWithCodeView extends StatefulWidget {
+  // Path of source file (relative to project root). The file's content will be
+  // shown in the "Code" tab.
+  final String sourceFilePath;
+  final Widget child;
+  final String? codeLinkPrefix;
+  final bool? showLabelText;
+  final Color? iconBackgroundColor;
+  final Color? iconForegroundColor;
+  final Color? labelBackgroundColor;
+  final TextStyle? labelTextStyle;
+  final SyntaxHighlighterStyle? syntaxHighlighterStyle;
+
+  const WidgetWithCodeView({
+    Key? key,
+    required this.child,
+    required this.sourceFilePath,
+    this.codeLinkPrefix,
+    this.showLabelText,
+    this.iconBackgroundColor,
+    this.iconForegroundColor,
+    this.labelBackgroundColor,
+    this.labelTextStyle,
+    this.syntaxHighlighterStyle,
+  }) : super(key: key);
+
+  static const _TABS = <Widget>[
+    Tab(
+      child: ListTile(
+        leading: Icon(Icons.phone_android, color: Colors.white),
+        title: Text('Preview', style: TextStyle(color: Colors.white)),
+      ),
+    ),
+    Tab(
+      child: ListTile(
+        leading: Icon(Icons.code, color: Colors.white),
+        title: Text('Code', style: TextStyle(color: Colors.white)),
+      ),
+    ),
+  ];
+
+  @override
+  _WidgetWithCodeViewState createState() => _WidgetWithCodeViewState();
+}
+
+class _WidgetWithCodeViewState extends State<WidgetWithCodeView>
+    with SingleTickerProviderStateMixin {
+  TabController? _tabController;
+
+  @override
+  void initState() {
+    super.initState();
+    _tabController = TabController(length: 2, vsync: this);
+  }
+
+  @override
+  void dispose() {
+    _tabController!.dispose();
+    super.dispose();
+  }
+
+  String get routeName => '/${this.runtimeType.toString()}';
+
+  Widget get sourceCodeView => SourceCodeView(
+        filePath: this.widget.sourceFilePath,
+        codeLinkPrefix: this.widget.codeLinkPrefix,
+        labelTextStyle: widget.labelTextStyle,
+        showLabelText: widget.showLabelText ?? true,
+        iconBackgroundColor: widget.iconBackgroundColor,
+        iconForegroundColor: widget.iconForegroundColor,
+        labelBackgroundColor: widget.labelBackgroundColor,
+        syntaxHighlighterStyle: widget.syntaxHighlighterStyle,
+      );
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: _ColoredTabBar(
+        color: Theme.of(context).primaryColor,
+        tabBar: TabBar(
+          controller: _tabController,
+          tabs: WidgetWithCodeView._TABS,
+        ),
+      ),
+      body: TabBarView(
+        controller: _tabController,
+        children: <Widget>[
+          _AlwaysAliveWidget(child: this.widget.child),
+          _AlwaysAliveWidget(child: this.sourceCodeView),
+        ],
+      ),
+    );
+  }
+}
+
+// This widget is always kept alive, so that when tab is switched back, its
+// child's state is still preserved.
+class _AlwaysAliveWidget extends StatefulWidget {
+  final Widget child;
+
+  const _AlwaysAliveWidget({Key? key, required this.child}) : super(key: key);
+
+  @override
+  _AlwaysAliveWidgetState createState() => _AlwaysAliveWidgetState();
+}
+
+class _AlwaysAliveWidgetState extends State<_AlwaysAliveWidget>
+    with AutomaticKeepAliveClientMixin<_AlwaysAliveWidget> {
+  @override
+  Widget build(BuildContext context) {
+    super.build(context); // This build method is annotated "@mustCallSuper".
+    return this.widget.child;
+  }
+
+  @override
+  bool get wantKeepAlive => true;
+}
+
+class _ColoredTabBar extends Container implements PreferredSizeWidget {
+  final Color color;
+  final TabBar tabBar;
+
+  _ColoredTabBar({Key? key, required this.color, required this.tabBar})
+      : super(key: key);
+
+  @override
+  Size get preferredSize => tabBar.preferredSize;
+
+  @override
+  Widget build(BuildContext context) => Material(
+        elevation: 4.0,
+        color: color,
+        child: tabBar,
+      );
+}
diff --git a/lib/widget_with_codeview.dart b/lib/widget_with_codeview.dart
index 3019623..5dd6da8 100644
--- a/lib/widget_with_codeview.dart
+++ b/lib/widget_with_codeview.dart
@@ -1,122 +1,2 @@
-library widget_with_codeview;
-
-import 'package:flutter/material.dart';
-
-import 'source_code_view.dart';
-
-class WidgetWithCodeView extends StatefulWidget {
-  // Path of source file (relative to project root). The file's content will be
-  // shown in the "Code" tab.
-  final String sourceFilePath;
-  final Widget child;
-  final String? codeLinkPrefix;
-
-  const WidgetWithCodeView({
-    Key? key,
-    required this.child,
-    required this.sourceFilePath,
-    this.codeLinkPrefix,
-  }) : super(key: key);
-
-  static const _TABS = <Widget>[
-    Tab(
-      child: ListTile(
-        leading: Icon(Icons.phone_android, color: Colors.white),
-        title: Text('Preview', style: TextStyle(color: Colors.white)),
-      ),
-    ),
-    Tab(
-      child: ListTile(
-        leading: Icon(Icons.code, color: Colors.white),
-        title: Text('Code', style: TextStyle(color: Colors.white)),
-      ),
-    ),
-  ];
-
-  @override
-  _WidgetWithCodeViewState createState() => _WidgetWithCodeViewState();
-}
-
-class _WidgetWithCodeViewState extends State<WidgetWithCodeView>
-    with SingleTickerProviderStateMixin {
-  TabController? _tabController;
-
-  @override
-  void initState() {
-    super.initState();
-    _tabController = TabController(length: 2, vsync: this);
-  }
-
-  @override
-  void dispose() {
-    _tabController!.dispose();
-    super.dispose();
-  }
-
-  String get routeName => '/${this.runtimeType.toString()}';
-
-  Widget get sourceCodeView => SourceCodeView(
-      filePath: this.widget.sourceFilePath,
-      codeLinkPrefix: this.widget.codeLinkPrefix);
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-      appBar: _ColoredTabBar(
-        color: Theme.of(context).primaryColor,
-        tabBar: TabBar(
-          controller: _tabController,
-          tabs: WidgetWithCodeView._TABS,
-        ),
-      ),
-      body: TabBarView(
-        controller: _tabController,
-        children: <Widget>[
-          _AlwaysAliveWidget(child: this.widget.child),
-          _AlwaysAliveWidget(child: this.sourceCodeView),
-        ],
-      ),
-    );
-  }
-}
-
-// This widget is always kept alive, so that when tab is switched back, its
-// child's state is still preserved.
-class _AlwaysAliveWidget extends StatefulWidget {
-  final Widget child;
-
-  const _AlwaysAliveWidget({Key? key, required this.child}) : super(key: key);
-
-  @override
-  _AlwaysAliveWidgetState createState() => _AlwaysAliveWidgetState();
-}
-
-class _AlwaysAliveWidgetState extends State<_AlwaysAliveWidget>
-    with AutomaticKeepAliveClientMixin<_AlwaysAliveWidget> {
-  @override
-  Widget build(BuildContext context) {
-    super.build(context); // This build method is annotated "@mustCallSuper".
-    return this.widget.child;
-  }
-
-  @override
-  bool get wantKeepAlive => true;
-}
-
-class _ColoredTabBar extends Container implements PreferredSizeWidget {
-  final Color color;
-  final TabBar tabBar;
-
-  _ColoredTabBar({Key? key, required this.color, required this.tabBar})
-      : super(key: key);
-
-  @override
-  Size get preferredSize => tabBar.preferredSize;
-
-  @override
-  Widget build(BuildContext context) => Material(
-        elevation: 4.0,
-        color: color,
-        child: tabBar,
-      );
-}
+export 'src/widget_with_codeview.dart';
+export 'src/syntax_highlighter.dart' show SyntaxHighlighterStyle;
diff --git a/pubspec.lock b/pubspec.lock
index cb0113e..bbac9e5 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -7,7 +7,7 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.5.0"
+    version: "2.6.1"
   boolean_selector:
     dependency: transitive
     description:
@@ -216,7 +216,7 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0"
+    version: "1.8.1"
   stack_trace:
     dependency: transitive
     description:
@@ -251,7 +251,7 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.19"
+    version: "0.3.0"
   typed_data:
     dependency: transitive
     description: