Window10搭建Flutter for Android环境

Flutter是谷歌的移动UI框架，可以快速在iOS和Android上构建高质量的原生用户界面。
目前，支持Windows、Linux、Mac OS以及Android和iOS，最新版本也已经支持Web（浏览器）平台。
本文大致记录下Flutter在Windows10下Android环境的搭建过程，一些细节步骤已经忽略。
环境搭建一旦成功，任务就已经成功了80%-90%，开始干！

系统环境：

软件清单：

• JDK：jdk-8u91-windows-x64.exe

• Android SDK：android-sdk_r24.4.1.zip 或 installer_r24.4.1-windows.exe

• Android Studio：android-studio-ide-192.6241897-windows.exe

• Flutter：flutter_windows_v1.12.13+hotfix.8-stable.zip

 

环境变量请参考资料自行添加。

执行flutter doctor时，可能存在问题：

Android license status unknow.
网上的资料都提示flutter doctor --android-licenses，但是需要升级Android SDK。
执行sdkmanager --update，命令窗口提示done，但是依旧提示升级Android SDK。
解决：在Android Studio中升级Android SDK Tools到可用最新版本，我这里原来是25.2.5，升级到了26.1.1就可以了！

在Android中新建Flutter工程，打开Android虚拟机，在main.dart窗口右键：

由于Android Studio比较重量级，很占用系统资源，而大家的电脑并不是都配置很高，此时可以切换到占用资源较小的VS Code上去。
为VS Code安装好Flutter插件：

打开Android虚拟机，打开Flutter工程，打开终端窗口（Ctrl+~）：flutter run

运行速度比Android Studio快多了~
体验热重载：修改下窗口标题，输入r立即执行效果

可能由于需要，需要切换Flutter SDK的版本，如果再编译之前的flutter工程可能会运行出错：

or: 'Matrix4' isn't a type.
    Matrix4 result = Matrix4.identity()
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/matrix_utils.dart:503:22: Error: Getter not found: 'Matrix4'.
    Matrix4 result = Matrix4.identity()
                     ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/matrix_utils.dart:512:15: Error: Getter not found: 'Matrix4'.
            ? Matrix4.rotationY(angle)
              ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/matrix_utils.dart:513:15: Error: Getter not found: 'Matrix4'.
            : Matrix4.rotationX(angle)
              ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/matrix_utils.dart:514:9: Error: Getter not found: 'Matrix4'.
    ) * Matrix4.translationValues(0.0, 0.0, radius);
        ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/matrix_utils.dart:522:12: Error: Getter not found: 'Matrix4'.
    return Matrix4.identity()
           ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/matrix_utils.dart:523:19: Error: Method not found: 'Vector4'.
      ..setRow(0, Vector4(0, 0, 0, offset.dx))
                  ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/matrix_utils.dart:524:19: Error: Method not found: 'Vector4'.
      ..setRow(1, Vector4(0, 0, 0, offset.dy));
                  ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/matrix_utils.dart:532:37: Error: 'Matrix4' isn't a type.
List<String> debugDescribeTransform(Matrix4 transform) {
                                    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/matrix_utils.dart:550:5: Error: 'Matrix4' isn't a type.
    Matrix4 value, {
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/rounded_rectangle_border.dart:147:6: Error: Getter not found: 'required'.
    @required this.circleness,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/rounded_rectangle_border.dart:147:6: Error: This can't be used as metadata; metadata should be a reference to
a compile-time constant variable, or a call to a constant constructor.
    @required this.circleness,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/shape_decoration.dart:78:6:
Error: Getter not found: 'required'.
    @required this.shape,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/shape_decoration.dart:78:6:
Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.shape,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/text_painter.dart:41:6: Error: Getter not found: 'required'.
    @required this.size,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/text_painter.dart:41:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.size,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/text_painter.dart:42:6: Error: Getter not found: 'required'.
    @required this.alignment,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/painting/text_painter.dart:42:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.alignment,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/drag_details.dart:135:6: Error: Getter not found: 'required'.
    @required this.globalPosition,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/drag_details.dart:135:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.globalPosition,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:450:9: Error: 'Matrix4' isn't a type.
  final Matrix4 transform;
        ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:475:28: Error: 'Matrix4' isn't a type.
  PointerEvent transformed(Matrix4 transform);
                           ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:518:35: Error: 'Matrix4' isn't a type.
  static Offset transformPosition(Matrix4 transform, Offset position) {
                                  ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:522:11: Error: 'Vector3' isn't a type.
    final Vector3 position3 = Vector3(position.dx, position.dy, 0.0);
          ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:522:31: Error: Method not found: 'Vector3'.
    final Vector3 position3 = Vector3(position.dx, position.dy, 0.0);
                              ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:523:11: Error: 'Vector3' isn't a type.
    final Vector3 transformed3 = transform.perspectiveTransform(position3);
          ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:535:6: Error: Getter not found: 'required'.
    @required Offset untransformedEndPosition,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:535:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required Offset untransformedEndPosition,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:537:6: Error: Getter not found: 'required'.
    @required Offset untransformedDelta,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:537:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required Offset untransformedDelta,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:538:6: Error: Getter not found: 'required'.
    @required Matrix4 transform,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:538:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required Matrix4 transform,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:538:15: Error: 'Matrix4' isn't a type.
    @required Matrix4 transform,
              ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:561:45: Error: 'Matrix4' isn't a type.
  static Matrix4 removePerspectiveTransform(Matrix4 transform) {
                                            ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:562:11: Error: 'Vector4' isn't a type.
    final Vector4 vector = Vector4(0, 0, 1, 0);
          ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:562:28: Error: Method not found: 'Vector4'.
    final Vector4 vector = Vector4(0, 0, 1, 0);
                           ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:592:5: Error: 'Matrix4' isn't a type.
    Matrix4 transform,
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:615:33: Error: 'Matrix4' isn't a type.
  PointerAddedEvent transformed(Matrix4 transform) {
                                ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:660:5: Error: 'Matrix4' isn't a type.
    Matrix4 transform,
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:680:35: Error: 'Matrix4' isn't a type.
  PointerRemovedEvent transformed(Matrix4 transform) {
                                  ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:738:5: Error: 'Matrix4' isn't a type.
    Matrix4 transform,
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:769:33: Error: 'Matrix4' isn't a type.
  PointerHoverEvent transformed(Matrix4 transform) {
                                ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:844:5: Error: 'Matrix4' isn't a type.
    Matrix4 transform,
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:914:33: Error: 'Matrix4' isn't a type.
  PointerEnterEvent transformed(Matrix4 transform) {
                                ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:990:5: Error: 'Matrix4' isn't a type.
    Matrix4 transform,
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:1060:32: Error:
'Matrix4' isn't a type.
  PointerExitEvent transformed(Matrix4 transform) {
                               ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:1124:5: Error: 'Matrix4' isn't a type.
    Matrix4 transform,
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:1153:32: Error:
'Matrix4' isn't a type.
  PointerDownEvent transformed(Matrix4 transform) {
                               ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:1218:5: Error: 'Matrix4' isn't a type.
    Matrix4 transform,
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:1251:32: Error:
'Matrix4' isn't a type.
  PointerMoveEvent transformed(Matrix4 transform) {
                               ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:1320:5: Error: 'Matrix4' isn't a type.
    Matrix4 transform,
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:1349:30: Error:
'Matrix4' isn't a type.
  PointerUpEvent transformed(Matrix4 transform) {
                             ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:1395:5: Error: 'Matrix4' isn't a type.
    Matrix4 transform,
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:1424:5: Error: 'Matrix4' isn't a type.
    Matrix4 transform,
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:1445:34: Error:
'Matrix4' isn't a type.
  PointerScrollEvent transformed(Matrix4 transform) {
                                 ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:1493:5: Error: 'Matrix4' isn't a type.
    Matrix4 transform,
    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/events.dart:1522:34: Error:
'Matrix4' isn't a type.
  PointerCancelEvent transformed(Matrix4 transform) {
                                 ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/force_press.dart:53:6: Error: Getter not found: 'required'.
    @required this.globalPosition,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/force_press.dart:53:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.globalPosition,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/force_press.dart:55:6: Error: Getter not found: 'required'.
    @required this.pressure,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/force_press.dart:55:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.pressure,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/hit_test.dart:68:3: Error: 'Matrix4' isn't a type.
  Matrix4 _transform;
  ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/hit_test.dart:76:28: Error:
'Matrix4' isn't a type.
       _transforms = Queue<Matrix4>();
                           ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/hit_test.dart:96:15: Error:
'Matrix4' isn't a type.
  final Queue<Matrix4> _transforms;
              ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/hit_test.dart:134:22: Error: 'Matrix4' isn't a type.
  void pushTransform(Matrix4 transform) {
                     ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/hit_test.dart:137:57: Error: The method 'Vector4' isn't defined for the class 'HitTestResult'.
 - 'HitTestResult' is from 'package:flutter/src/gestures/hit_test.dart' ('/D:/GitWork/flutter/packages/flutter/lib/src/gestures/hit_test.dart').
Try correcting the name to the name of an existing method, or defining a method named 'Vector4'.
      _debugVectorMoreOrLessEquals(transform.getRow(2), Vector4(0, 0, 1, 0)) &&
                                                        ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/hit_test.dart:138:60: Error: The method 'Vector4' isn't defined for the class 'HitTestResult'.
 - 'HitTestResult' is from 'package:flutter/src/gestures/hit_test.dart' ('/D:/GitWork/flutter/packages/flutter/lib/src/gestures/hit_test.dart').
Try correcting the name to the name of an existing method, or defining a method named 'Vector4'.
      _debugVectorMoreOrLessEquals(transform.getColumn(2), Vector4(0, 0, 1, 0)),
                                                           ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/hit_test.dart:167:37: Error: 'Vector4' isn't a type.
  bool _debugVectorMoreOrLessEquals(Vector4 a, Vector4 b, { double epsilon = precisionErrorTolerance }) {
                                    ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/hit_test.dart:167:48: Error: 'Vector4' isn't a type.
  bool _debugVectorMoreOrLessEquals(Vector4 a, Vector4 b, { double epsilon = precisionErrorTolerance }) {
                                               ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/hit_test.dart:170:13: Error: 'Vector4' isn't a type.
      final Vector4 difference = a - b;
            ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/monodrag.dart:179:3: Error:
'Matrix4' isn't a type.
  Matrix4 _lastTransform;
  ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/monodrag.dart:270:15: Error: 'Matrix4' isn't a type.
        final Matrix4 localToGlobalTransform = event.transform == null ? null : Matrix4.tryInvert(event.transform);
              ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/monodrag.dart:270:81: Error: The getter 'Matrix4' isn't defined for the class 'DragGestureRecognizer'.
 - 'DragGestureRecognizer' is from 'package:flutter/src/gestures/monodrag.dart' ('/D:/GitWork/flutter/packages/flutter/lib/src/gestures/monodrag.dart').
Try correcting the name to the name of an existing getter, or defining a getter or field named 'Matrix4'.
        final Matrix4 localToGlobalTransform = event.transform == null ? null : Matrix4.tryInvert(event.transform);
                                                                                ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/monodrag.dart:294:13: Error: 'Matrix4' isn't a type.
      final Matrix4 transform = _lastTransform;
            ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/monodrag.dart:310:15: Error: 'Matrix4' isn't a type.
        final Matrix4 localToGlobal = transform != null ? Matrix4.tryInvert(transform) : null;
              ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/monodrag.dart:310:59: Error: The getter 'Matrix4' isn't defined for the class 'DragGestureRecognizer'.
 - 'DragGestureRecognizer' is from 'package:flutter/src/gestures/monodrag.dart' ('/D:/GitWork/flutter/packages/flutter/lib/src/gestures/monodrag.dart').
Try correcting the name to the name of an existing getter, or defining a getter or field named 'Matrix4'.
        final Matrix4 localToGlobal = transform != null ? Matrix4.tryInvert(transform) : null;
                                                          ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/mouse_tracking.dart:78:6: Error: Getter not found: 'required'.
    @required PointerEvent mostRecentEvent,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/mouse_tracking.dart:78:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required PointerEvent mostRecentEvent,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/mouse_tracking.dart:293:6: Error: Getter not found: 'required'.
    @required LinkedHashSet<MouseTrackerAnnotation> nextAnnotations,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/mouse_tracking.dart:293:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required LinkedHashSet<MouseTrackerAnnotation> nextAnnotations,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/mouse_tracking.dart:294:6: Error: Getter not found: 'required'.
    @required _MouseState currentState,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/mouse_tracking.dart:294:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required _MouseState currentState,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/multidrag.dart:196:6: Error: Getter not found: 'required'.
    @required Object debugOwner,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/multidrag.dart:196:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time
constant variable, or a call to a constant constructor.
    @required Object debugOwner,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/multitap.dart:44:22: Error:
Getter not found: 'required'.
  _CountdownZoned({ @required Duration duration })
                     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/multitap.dart:44:22: Error:
This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
  _CountdownZoned({ @required Duration duration })
                     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/multitap.dart:62:6: Error: Getter not found: 'required'.
    @required PointerDownEvent event,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/multitap.dart:62:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required PointerDownEvent event,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/multitap.dart:64:6: Error: Getter not found: 'required'.
    @required Duration doubleTapMinTime,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/multitap.dart:64:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required Duration doubleTapMinTime,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/multitap.dart:81:49: Error:
'Matrix4' isn't a type.
  void startTrackingPointer(PointerRoute route, Matrix4 transform) {
                                                ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:15:36: Error: 'Matrix4' isn't a type.
  final Map<int, Map<PointerRoute, Matrix4>> _routeMap = <int, Map<PointerRoute, Matrix4>>{};
                                   ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:15:82: Error: 'Matrix4' isn't a type.
  final Map<int, Map<PointerRoute, Matrix4>> _routeMap = <int, Map<PointerRoute, Matrix4>>{};
                                                                                 ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:16:27: Error: 'Matrix4' isn't a type.
  final Map<PointerRoute, Matrix4> _globalRoutes = <PointerRoute, Matrix4>{};
                          ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:16:67: Error: 'Matrix4' isn't a type.
  final Map<PointerRoute, Matrix4> _globalRoutes = <PointerRoute, Matrix4>{};
                                                                  ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:25:51: Error: 'Matrix4' isn't a type.
  void addRoute(int pointer, PointerRoute route, [Matrix4 transform]) {
                                                  ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:26:29: Error: 'Matrix4' isn't a type.
    final Map<PointerRoute, Matrix4> routes = _routeMap.putIfAbsent(
                            ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:28:28: Error: 'Matrix4' isn't a type.
      () => <PointerRoute, Matrix4>{},
                           ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:43:29: Error: 'Matrix4' isn't a type.
    final Map<PointerRoute, Matrix4> routes = _routeMap[pointer];
                            ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:56:44: Error: 'Matrix4' isn't a type.
  void addGlobalRoute(PointerRoute route, [Matrix4 transform]) {
                                           ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:73:58: Error: 'Matrix4' isn't a type.
  void _dispatch(PointerEvent event, PointerRoute route, Matrix4 transform) {
                                                         ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:98:29: Error: 'Matrix4' isn't a type.
    final Map<PointerRoute, Matrix4> routes = _routeMap[event.pointer];
                            ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:99:29: Error: 'Matrix4' isn't a type.
    final Map<PointerRoute, Matrix4> copiedGlobalRoutes = Map<PointerRoute, Matrix4>.from(_globalRoutes);
                            ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:99:77: Error: 'Matrix4' isn't a type.
    final Map<PointerRoute, Matrix4> copiedGlobalRoutes = Map<PointerRoute, Matrix4>.from(_globalRoutes);
                                                                            ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:104:27:
Error: 'Matrix4' isn't a type.
        Map<PointerRoute, Matrix4>.from(routes),
                          ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:112:23:
Error: 'Matrix4' isn't a type.
    Map<PointerRoute, Matrix4> referenceRoutes,
                      ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:113:23:
Error: 'Matrix4' isn't a type.
    Map<PointerRoute, Matrix4> copiedRoutes,
                      ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/pointer_router.dart:115:47:
Error: 'Matrix4' isn't a type.
    copiedRoutes.forEach((PointerRoute route, Matrix4 transform) {
                                              ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/recognizer.dart:317:43: Error: 'Matrix4' isn't a type.
  void startTrackingPointer(int pointer, [Matrix4 transform]) {
                                          ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/recognizer.dart:549:6: Error: Getter not found: 'required'.
    @required this.local,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/recognizer.dart:549:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.local,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/recognizer.dart:550:6: Error: Getter not found: 'required'.
    @required this.global,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/recognizer.dart:550:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.global,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/scale.dart:243:3: Error: 'Matrix4' isn't a type.
  Matrix4 _lastTransform;
  ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/velocity_tracker.dart:19:6:
Error: Getter not found: 'required'.
    @required this.pixelsPerSecond,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/velocity_tracker.dart:19:6:
Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.pixelsPerSecond,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/velocity_tracker.dart:97:6:
Error: Getter not found: 'required'.
    @required this.pixelsPerSecond,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/velocity_tracker.dart:97:6:
Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.pixelsPerSecond,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/velocity_tracker.dart:98:6:
Error: Getter not found: 'required'.
    @required this.confidence,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/velocity_tracker.dart:98:6:
Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.confidence,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/velocity_tracker.dart:99:6:
Error: Getter not found: 'required'.
    @required this.duration,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/velocity_tracker.dart:99:6:
Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.duration,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/velocity_tracker.dart:100:6: Error: Getter not found: 'required'.
    @required this.offset,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/gestures/velocity_tracker.dart:100:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.offset,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:100:33: Error: Getter not found: 'required'.
  const CustomSemanticsAction({@required this.label})
                                ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:100:33: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
  const CustomSemanticsAction({@required this.label})
                                ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:110:50: Error: Getter not found: 'required'.
  const CustomSemanticsAction.overridingAction({@required this.hint, @required this.action})
                                                 ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:110:50: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
  const CustomSemanticsAction.overridingAction({@required this.hint, @required this.action})
                                                 ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:110:71: Error: Getter not found: 'required'.
  const CustomSemanticsAction.overridingAction({@required this.hint, @required this.action})
                                                                      ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:110:71: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
  const CustomSemanticsAction.overridingAction({@required this.hint, @required this.action})
                                                                      ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:182:6: Error: Getter not found: 'required'.
    @required this.flags,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:182:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.flags,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:183:6: Error: Getter not found: 'required'.
    @required this.actions,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:183:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.actions,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:184:6: Error: Getter not found: 'required'.
    @required this.label,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:184:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.label,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:185:6: Error: Getter not found: 'required'.
    @required this.increasedValue,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:185:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.increasedValue,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:186:6: Error: Getter not found: 'required'.
    @required this.value,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:186:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.value,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:187:6: Error: Getter not found: 'required'.
    @required this.decreasedValue,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:187:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.decreasedValue,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:188:6: Error: Getter not found: 'required'.
    @required this.hint,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:188:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.hint,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:189:6: Error: Getter not found: 'required'.
    @required this.textDirection,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:189:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.textDirection,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:190:6: Error: Getter not found: 'required'.
    @required this.rect,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:190:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.rect,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:191:6: Error: Getter not found: 'required'.
    @required this.elevation,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:191:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.elevation,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:192:6: Error: Getter not found: 'required'.
    @required this.thickness,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:192:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.thickness,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:193:6: Error: Getter not found: 'required'.
    @required this.textSelection,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:193:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.textSelection,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:194:6: Error: Getter not found: 'required'.
    @required this.scrollIndex,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:194:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.scrollIndex,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:195:6: Error: Getter not found: 'required'.
    @required this.scrollChildCount,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:195:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.scrollChildCount,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:196:6: Error: Getter not found: 'required'.
    @required this.scrollPosition,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:196:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.scrollPosition,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:197:6: Error: Getter not found: 'required'.
    @required this.scrollExtentMax,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:197:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.scrollExtentMax,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:198:6: Error: Getter not found: 'required'.
    @required this.scrollExtentMin,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:198:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.scrollExtentMin,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:199:6: Error: Getter not found: 'required'.
    @required this.platformViewId,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:199:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.platformViewId,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:200:6: Error: Getter not found: 'required'.
    @required this.maxValueLength,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:200:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.maxValueLength,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:201:6: Error: Getter not found: 'required'.
    @required this.currentValueLength,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:201:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.currentValueLength,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:345:9: Error: 'Matrix4' isn't a type.
  final Matrix4 transform;
        ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:502:6: Error: Getter not found: 'required'.
    @required SemanticsNode value,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:502:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required SemanticsNode value,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:503:6: Error: Getter not found: 'required'.
    @required DiagnosticsTreeStyle style,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:503:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required DiagnosticsTreeStyle style,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:504:6: Error: Getter not found: 'required'.
    @required this.childOrder,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:504:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.childOrder,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:1232:3: Error: 'Matrix4' isn't a type.
  Matrix4 _transform;
  ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:1233:17: Error: 'Matrix4' isn't a type.
  set transform(Matrix4 value) {
                ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:1840:6: Error: Getter not found: 'required'.
    @required SemanticsConfiguration config,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:1840:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required SemanticsConfiguration config,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2029:12: Error: Getter not found: 'Matrix4'.
    return Matrix4.identity().storage;
           ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2299:6: Error: Getter not found: 'required'.
    @required this.isLeadingEdge,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2299:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.isLeadingEdge,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2300:6: Error: Getter not found: 'required'.
    @required this.offset,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2300:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.offset,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2301:6: Error: Getter not found: 'required'.
    @required this.node,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2301:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.node,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2337:6: Error: Getter not found: 'required'.
    @required this.startOffset,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2337:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.startOffset,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2338:6: Error: Getter not found: 'required'.
    @required this.textDirection,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2338:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.textDirection,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2489:9: Error: 'Vector3' isn't a type.
  final Vector3 vector = Vector3(point.dx, point.dy, 0.0);
        ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2489:26: Error: Method not found: 'Vector3'.
  final Vector3 vector = Vector3(point.dx, point.dy, 0.0);
                         ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2559:6: Error: Getter not found: 'required'.
    @required this.node,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2559:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.node,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2561:6: Error: Getter not found: 'required'.
    @required this.position,
     ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2561:6: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
    @required this.position,
     ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2699:13: Error: 'Matrix4' isn't a type.
      final Matrix4 inverse = Matrix4.identity();
            ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:2699:31: Error: The getter 'Matrix4' isn't defined for the class 'SemanticsOwner'.
 - 'SemanticsOwner' is from 'package:flutter/src/semantics/semantics.dart' ('/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart').
Try correcting the name to the name of an existing getter, or defining a getter or field named 'Matrix4'.
      final Matrix4 inverse = Matrix4.identity();
                              ^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:3968:4: Error: Getter not found: 'required'.
  @required String thisString,
   ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:3968:4: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
  @required String thisString,
   ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:3969:4: Error: Getter not found: 'required'.
  @required String otherString,
   ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:3969:4: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
  @required String otherString,
   ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:3970:4: Error: Getter not found: 'required'.
  @required TextDirection thisTextDirection,
   ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:3970:4: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
  @required TextDirection thisTextDirection,
   ^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:3971:4: Error: Getter not found: 'required'.
  @required TextDirection otherTextDirection,
   ^^^^^^^^
/D:/GitWork/flutter/packages/flutter/lib/src/semantics/semantics.dart:3971:4: Error: This can't be used as metadata; metadata should be a reference to a compile-time constant variable, or a call to a constant constructor.
  @required TextDirection otherTextDirection,
   ^
Target kernel_snapshot failed: Exception: Errors during snapshot creation: null
build failed.

FAILURE: Build failed with an exception.

* Where:
Script 'D:GitWorkflutterpackagesflutter_toolsgradleflutter.gradle' line: 780
* What went wrong:
Execution failed for task ':app:compileFlutterBuildDebug'.
> Process 'command 'D:GitWorkflutterinflutter.bat'' finished with non-zero exit value 1

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 7s
Running Gradle task 'assembleDebug'...
Running Gradle task 'assembleDebug'... Done                        18.9s
Gradle task assembleDebug failed with exit code 1

检查flutter doctor也没有问题，这是由于之前建立的flutter工程是另外一个flutter SDK版本导致的，此时可以重新在当前flutter SDK上建立工程，或使用examples中自带的工程即可。