Clean codes & add features & fix bugs

Features/Bugs:
- Feature: You can select what classes needs to be rebuilt instead of rebuilding everything, if you have widget A, either addi SU mixin or add 'A' to list ScreenUtilInit.responsiveWidgets
- Feature: Using ScreenUtilInit.builder is optional (use it only when using library in theme)
- Bug: Second call to ScreenUtil.init ignores any existing values and uses the default values when not provided, use ScreenUtil.configure instead
- Bug: ScreenUtil.ensureScreenSize raises an overflow error

@@ -139,3 +139,6 @@ doc
 .lock
 coverage*
 *.lock
+
+# Don't commit .fvm directory containing machine-specific symlink to sdk & flutter version
+**/.fvm

+/////////////////////////////////////////////////////////////////////////
+/// Generated via plugin: flutter_screenutil_generator - Do Not Touch ///
+/////////////////////////////////////////////////////////////////////////
+
+part of 'responsive_widgets.su.dart';
+
+const _responsiveWidgets = {
+  'MyThemedApp',
+  'MyApp',
+  'HomePageScaffold',
+};

+part 'responsive_widgets.g.dart';
+
+get responsiveWidgets => _responsiveWidgets;

+import 'package:example/responsive_widgets.su.dart';
 import 'package:example/src/home.dart';
 import 'package:flutter/material.dart';
+// import 'package:example/allowed_classes.su.dart';
 import 'package:flutter_screenutil/flutter_screenutil.dart';
 
 class MyApp extends StatelessWidget {
@@ -9,22 +11,19 @@ class MyApp extends StatelessWidget {
   Widget build(BuildContext context) {
     // In first method you only need to wrap [MaterialApp] with [ScreenUtilInit] and that's it
     return ScreenUtilInit(
-      useInheritedMediaQuery: false,
-      builder: (_, child) {
-        return MaterialApp(
-          debugShowCheckedModeBanner: false,
-          title: 'First Method',
-          // You can use the library anywhere in the app even in theme
-          theme: ThemeData(
-            primarySwatch: Colors.blue,
-            textTheme: Typography(platform: TargetPlatform.iOS)
-                .black
-                .apply(fontSizeFactor: 1),
-          ),
-          home: child,
-        );
-      },
-      child: const HomePage(title: 'First Method'),
+      responsiveWidgets: responsiveWidgets,
+      child: MaterialApp(
+        debugShowCheckedModeBanner: false,
+        title: 'First Method',
+        // You can use the library anywhere in the app even in theme
+        theme: ThemeData(
+          primarySwatch: Colors.blue,
+          textTheme: Typography(platform: TargetPlatform.iOS)
+              .black
+              .apply(fontSizeFactor: 1),
+        ),
+        home: const HomePage(title: 'First Method'),
+      ),
     );
   }
 }

@@ -2,7 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_screenutil/flutter_screenutil.dart';
 
-class HomePageScaffold extends StatelessWidget {
+class HomePageScaffold extends StatelessWidget with SU {
   const HomePageScaffold({Key? key, this.title = ''}) : super(key: key);
 
   void printScreenInformation(BuildContext context) {

@@ -25,6 +25,9 @@ dev_dependencies:
   flutter_test:
     sdk: flutter
   test: ^1.15.7
+  build_runner:
+  flutter_screenutil_generator:
+    path: ../../flutter_screenutil_generator
 
 flutter:
-  uses-material-design: true
\ No newline at end of file
+  uses-material-design: true

@@ -10,3 +10,4 @@ export 'src/r_sizedbox.dart';
 export 'src/screen_util.dart';
 export 'src/screenutil_init.dart';
 export 'src/size_extension.dart';
+export 'src/screenutil_mixin.dart';

@@ -4,8 +4,7 @@
  */
 
 import 'dart:math' show min, max;
-import 'dart:ui' show FlutterView;
-import 'dart:async' show Completer;
+import 'dart:ui' as ui show FlutterView;
 
 import 'package:flutter/widgets.dart';
 
@@ -20,10 +19,8 @@ class ScreenUtil {
   ///屏幕方向
   late Orientation _orientation;
 
-  late double _screenWidth;
-  late double _screenHeight;
   late bool _minTextAdapt;
-  BuildContext? _context;
+  late MediaQueryData _data;
   late bool _splitScreenMode;
 
   ScreenUtil._();
@@ -32,6 +29,22 @@ class ScreenUtil {
     return _instance;
   }
 
+  factory ScreenUtil.init(
+    BuildContext context, {
+    Size designSize = defaultSize,
+    bool splitScreenMode = false,
+    bool minTextAdapt = false,
+  }) {
+    configure(
+      data: MediaQuery.maybeOf(context),
+      designSize: designSize,
+      minTextAdapt: minTextAdapt,
+      splitScreenMode: splitScreenMode,
+    );
+
+    return _instance;
+  }
+
   /// Manually wait for window size to be initialized
   ///
   /// `Recommended` to use before you need access window size
@@ -55,19 +68,25 @@ class ScreenUtil {
   ///   )
   /// ```
   static Future<void> ensureScreenSize([
-    FlutterView? window,
+    ui.FlutterView? window,
     Duration duration = const Duration(milliseconds: 10),
   ]) async {
     final binding = WidgetsFlutterBinding.ensureInitialized();
-    window ??= WidgetsBinding.instance.platformDispatcher.implicitView;
+    binding.deferFirstFrame();
 
-    if (window?.physicalGeometry.isEmpty == true) {
-      return Future.delayed(duration, () async {
-        binding.deferFirstFrame();
-        await ensureScreenSize(window, duration);
-        return binding.allowFirstFrame();
-      });
-    }
+    await Future.doWhile(() {
+      if (window == null) {
+        window = binding.platformDispatcher.implicitView;
+      }
+
+      if (window == null || window!.physicalGeometry.isEmpty == true) {
+        return Future.delayed(duration, () => true);
+      }
+
+      return false;
+    });
+
+    binding.allowFirstFrame();
   }
 
   Set<Element>? _elementsToRebuild;
@@ -89,43 +108,30 @@ class ScreenUtil {
   }
 
   /// Initializing the library.
-  static Future<void> init(BuildContext context,
-      {Size designSize = defaultSize,
-      bool splitScreenMode = false,
-      bool minTextAdapt = false,
-      bool scaleByHeight = false}) async {
-    final mediaQueryContext =
-        context.getElementForInheritedWidgetOfExactType<MediaQuery>();
-
-    final initCompleter = Completer<void>();
-
-    WidgetsFlutterBinding.ensureInitialized().addPostFrameCallback((_) {
-      mediaQueryContext?.visitChildElements((el) => _instance._context = el);
-      if (_instance._context != null) initCompleter.complete();
-    });
+  static void configure({
+    MediaQueryData? data,
+    Size? designSize,
+    bool? splitScreenMode,
+    bool? minTextAdapt,
+  }) {
+    if (data != null) _instance._data = data;
+
+    final deviceData = _instance._data.nonEmptySizeOrNull();
+    final deviceSize = deviceData?.size ?? designSize ?? _instance._uiSize;
 
-    final deviceData = MediaQuery.maybeOf(context).nonEmptySizeOrNull();
+    if (designSize != null) _instance._uiSize = designSize;
 
-    final deviceSize = deviceData?.size ?? designSize;
     final orientation = deviceData?.orientation ??
         (deviceSize.width > deviceSize.height
             ? Orientation.landscape
             : Orientation.portrait);
 
     _instance
-      .._context = scaleByHeight ? null : context
-      .._uiSize = designSize
-      .._splitScreenMode = splitScreenMode
-      .._minTextAdapt = minTextAdapt
-      .._orientation = orientation
-      .._screenWidth = scaleByHeight
-          ? (deviceSize.height * designSize.width) / designSize.height
-          : deviceSize.width
-      .._screenHeight = deviceSize.height;
+      .._minTextAdapt = minTextAdapt ?? _instance._minTextAdapt
+      .._splitScreenMode = splitScreenMode ?? _instance._splitScreenMode
+      .._orientation = orientation;
 
     _instance._elementsToRebuild?.forEach((el) => el.markNeedsBuild());
-
-    return initCompleter.future;
   }
 
   ///获取屏幕方向
@@ -134,33 +140,27 @@ class ScreenUtil {
 
   /// 每个逻辑像素的字体像素数，字体的缩放比例
   /// The number of font pixels for each logical pixel.
-  double get textScaleFactor =>
-      _context != null ? MediaQuery.of(_context!).textScaleFactor : 1;
+  double get textScaleFactor => _data.textScaleFactor;
 
   /// 设备的像素密度
   /// The size of the media in logical pixels (e.g, the size of the screen).
-  double? get pixelRatio =>
-      _context != null ? MediaQuery.of(_context!).devicePixelRatio : 1;
+  double? get pixelRatio => _data.devicePixelRatio;
 
   /// 当前设备宽度 dp
   /// The horizontal extent of this size.
-  double get screenWidth =>
-      _context != null ? MediaQuery.of(_context!).size.width : _screenWidth;
+  double get screenWidth => _data.size.width;
 
   ///当前设备高度 dp
   ///The vertical extent of this size. dp
-  double get screenHeight =>
-      _context != null ? MediaQuery.of(_context!).size.height : _screenHeight;
+  double get screenHeight => _data.size.height;
 
   /// 状态栏高度 dp 刘海屏会更高
   /// The offset from the top, in dp
-  double get statusBarHeight =>
-      _context == null ? 0 : MediaQuery.of(_context!).padding.top;
+  double get statusBarHeight => _data.padding.top;
 
   /// 底部安全区距离 dp
   /// The offset from the bottom, in dp
-  double get bottomBarHeight =>
-      _context == null ? 0 : MediaQuery.of(_context!).padding.bottom;
+  double get bottomBarHeight => _data.padding.bottom;
 
   /// 实际尺寸与UI设计的比例
   /// The ratio of actual width to UI design

 import 'package:flutter/widgets.dart';
 
+import 'screenutil_mixin.dart';
 import 'screen_util.dart';
 
 typedef RebuildFactor = bool Function(MediaQueryData old, MediaQueryData data);
@@ -9,9 +10,7 @@ typedef ScreenUtilInitBuilder = Widget Function(
   Widget? child,
 );
 
-class RebuildFactors {
-  const RebuildFactors._();
-
+abstract class RebuildFactors {
   static bool size(MediaQueryData old, MediaQueryData data) {
     return old.size != data.size;
   }
@@ -24,35 +23,43 @@ class RebuildFactors {
     return old.viewInsets != data.viewInsets;
   }
 
-  static bool all(MediaQueryData old, MediaQueryData data) {
+  static bool change(MediaQueryData old, MediaQueryData data) {
     return old != data;
   }
+
+  static bool always(MediaQueryData _, MediaQueryData __) {
+    return true;
+  }
+
+  static bool none(MediaQueryData _, MediaQueryData __) {
+    return false;
+  }
 }
 
 class ScreenUtilInit extends StatefulWidget {
   /// A helper widget that initializes [ScreenUtil]
-  const ScreenUtilInit(
-      {Key? key,
-      required this.builder,
-      this.child,
-      this.rebuildFactor = RebuildFactors.size,
-      this.designSize = ScreenUtil.defaultSize,
-      this.splitScreenMode = false,
-      this.minTextAdapt = false,
-      this.useInheritedMediaQuery = false,
-      this.scaleByHeight = false})
-      : super(key: key);
-
-  final ScreenUtilInitBuilder builder;
+  const ScreenUtilInit({
+    Key? key,
+    this.builder,
+    this.child,
+    this.rebuildFactor = RebuildFactors.size,
+    this.designSize = ScreenUtil.defaultSize,
+    this.splitScreenMode = false,
+    this.minTextAdapt = false,
+    this.useInheritedMediaQuery = false,
+    this.responsiveWidgets,
+  }) : super(key: key);
+
+  final ScreenUtilInitBuilder? builder;
   final Widget? child;
   final bool splitScreenMode;
   final bool minTextAdapt;
   final bool useInheritedMediaQuery;
-  final bool scaleByHeight;
   final RebuildFactor rebuildFactor;
 
   /// The [Size] of the device in the design draft, in dp
   final Size designSize;
+  final Iterable<String>? responsiveWidgets;
 
   @override
   State<ScreenUtilInit> createState() => _ScreenUtilInitState();
@@ -60,127 +67,85 @@ class ScreenUtilInit extends StatefulWidget {
 
 class _ScreenUtilInitState extends State<ScreenUtilInit>
     with WidgetsBindingObserver {
+  late final Iterable<String>? _canMarkedToBuild;
   MediaQueryData? _mediaQueryData;
+  final WidgetsBinding _binding = WidgetsBinding.instance;
+
+  @override
+  void initState() {
+    _canMarkedToBuild = widget.responsiveWidgets;
+    super.initState();
+    _binding.addObserver(this);
+  }
+
+  @override
+  void didChangeMetrics() {
+    super.didChangeMetrics();
+    _revalidate();
+  }
 
-  bool wrappedInMediaQuery = false;
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    _revalidate();
+  }
 
-  WidgetsBinding get binding => WidgetsFlutterBinding.ensureInitialized();
+  MediaQueryData? _newData() {
+    MediaQueryData? mq = MediaQuery.maybeOf(context);
+    if (mq == null) mq = MediaQueryData.fromView(View.of(context));
 
-  MediaQueryData get mediaQueryData => _mediaQueryData!;
+    return mq;
+  }
 
-  MediaQueryData get newData {
-    final data = MediaQuery.maybeOf(context);
+  void _markNeedsBuildIfAllowed(Element el) {
+    if (_canMarkedToBuild != null) {
+      final widget = el.widget, widgetName = el.widget.runtimeType.toString();
 
-    if (data != null) {
-      if (widget.useInheritedMediaQuery) {
-        wrappedInMediaQuery = true;
-      }
-      return data;
+      if (widget is! SU && !_canMarkedToBuild!.contains(widgetName)) return;
     }
 
-    return MediaQueryData.fromView(View.of(context));
+    el.markNeedsBuild();
   }
 
-  _updateTree(Element el) {
-    el.markNeedsBuild();
+  void _updateTree(Element el) {
+    _markNeedsBuildIfAllowed(el);
     el.visitChildren(_updateTree);
   }
 
-  @override
-  void initState() {
-    super.initState();
-    binding.addObserver(this);
-  }
+  void _revalidate([void Function()? callback]) {
+    final oldData = _mediaQueryData;
+    final newData = _newData();
 
-  @override
-  void didChangeMetrics() {
-    final old = _mediaQueryData!;
-    final data = newData;
+    if (newData == null) return;
 
-    if (widget.scaleByHeight || widget.rebuildFactor(old, data)) {
-      _mediaQueryData = data;
-      _updateTree(context as Element);
+    if (oldData == null || widget.rebuildFactor(oldData, newData)) {
+      setState(() {
+        _mediaQueryData = newData;
+        _updateTree(context as Element);
+        callback?.call();
+      });
     }
   }
 
   @override
-  void didChangeDependencies() {
-    super.didChangeDependencies();
-    if (_mediaQueryData == null) _mediaQueryData = newData;
-    didChangeMetrics();
-  }
-
-  @override
-  void dispose() {
-    binding.removeObserver(this);
-    super.dispose();
-  }
+  Widget build(BuildContext context) {
+    final mq = _mediaQueryData;
 
-  @override
-  Widget build(BuildContext _context) {
-    if (mediaQueryData.size == Size.zero) return const SizedBox.shrink();
-    if (!wrappedInMediaQuery) {
-      return MediaQuery(
-        data: mediaQueryData,
-        child: Builder(
-          builder: (__context) {
-            ScreenUtil.init(
-              __context,
-              designSize: widget.designSize,
-              splitScreenMode: widget.splitScreenMode,
-              minTextAdapt: widget.minTextAdapt,
-              scaleByHeight: widget.scaleByHeight,
-            );
-            final deviceData = MediaQuery.maybeOf(__context);
-            final deviceSize = deviceData?.size ?? widget.designSize;
-            return MediaQuery(
-              data: MediaQueryData.fromView(View.of(__context)),
-              child: Container(
-                width: deviceSize.width,
-                height: deviceSize.height,
-                child: FittedBox(
-                  fit: BoxFit.none,
-                  alignment: Alignment.center,
-                  child: Container(
-                    width: widget.scaleByHeight
-                        ? (deviceSize.height * widget.designSize.width) /
-                            widget.designSize.height
-                        : deviceSize.width,
-                    height: deviceSize.height,
-                    child: widget.builder(__context, widget.child),
-                  ),
-                ),
-              ),
-            );
-          },
-        ),
-      );
-    }
+    if (mq == null) return SizedBox.shrink();
 
-    ScreenUtil.init(
-      _context,
+    ScreenUtil.configure(
+      data: mq,
       designSize: widget.designSize,
       splitScreenMode: widget.splitScreenMode,
       minTextAdapt: widget.minTextAdapt,
-      scaleByHeight: widget.scaleByHeight,
-    );
-    final deviceData = MediaQuery.maybeOf(_context);
-    final deviceSize = deviceData?.size ?? widget.designSize;
-    return Container(
-      width: deviceSize.width,
-      height: deviceSize.height,
-      child: FittedBox(
-        fit: BoxFit.none,
-        alignment: Alignment.center,
-        child: Container(
-          width: widget.scaleByHeight
-              ? (deviceSize.height * widget.designSize.width) /
-                  widget.designSize.height
-              : deviceSize.width,
-          height: deviceSize.height,
-          child: widget.builder(_context, widget.child),
-        ),
-      ),
     );
+
+    return widget.builder?.call(context, widget.child) ?? widget.child!;
+  }
+
+  @override
+  void dispose() {
+    _binding.removeObserver(this);
+    super.dispose();
   }
 }

+import 'package:flutter/widgets.dart';
+
+mixin SU on Widget {}

@@ -14,3 +14,4 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
+  build_runner: