title: How to solved 'dart:ui' error when going to run flutter app?
body: <p><a href="https://i.stack.imgur.com/I5Q7O.png" rel="noreferrer"><img src="https://i.stack.imgur.com/I5Q7O.png" alt="enter image description here" /></a>Below error occurs when I try to run my first flutter app.</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>file:///Volumes/Data/FlutterSDk/flutter/packages/flutter/lib/src/cupertino/action_sheet.dart:5:8: Error: Not found: 'dart:ui'
  import 'dart:ui' show ImageFilter;
         ^
   file:///Volumes/Data/FlutterSDk/flutter/packages/flutter/lib/src/cupertino/bottom_tab_bar.dart:5:8: Error: Not found: 'dart:ui'
  import 'dart:ui' show ImageFilter;
         ^
  file:///Volumes/Data/FlutterSDk/flutter/packages/flutter/lib/src/cupertino/colors.dart:5:8: Error: Not found: 'dart:ui'
  import 'dart:ui' show Color;
         ^
  file:///Volumes/Data/FlutterSDk/flutter/packages/flutter/lib/src/cupertino/dialog.dart:6:8: Error: Not found: 'dart:ui'
  import 'dart:ui' show ImageFilter;
         ^
   file:///Volumes/Data/FlutterSDk/flutter/packages/flutter/lib/src/cupertino/nav_bar.dart:6:8: Error: Not found: 'dart:ui'
  import 'dart:ui' show ImageFilter;
         ^
   file:///Volumes/Data/FlutterSDk/flutter/packages/flutter/lib/src/cupertino/slider.dart:6:8: Error: Not found: 'dart:ui'
  import 'dart:ui' show lerpDouble;
         ^
   file:///Volumes/Data/FlutterSDk/flutter/packages/flutter/lib/src/cupertino/switch.dart:6:8: Error: Not found: 'dart:ui'
  import 'dart:ui' show lerpDouble;
         ^
   file:///Volumes/Data/FlutterSDk/flutter/packages/flutter/lib/src/material/animated_icons.dart:9:8: Error: Not found: 'dart:ui'
  import 'dart:ui' as ui show Paint, Path, Canvas;
         ^   file:///Volumes/Data/FlutterSDk/flutter/packages/flutter/lib/src/material/animated_icons.dart:10:8: Error: Not found: 'dart:ui'
  import 'dart:ui' show lerpDouble;
         ^  file:///Volumes/Data/FlutterSDk/flutter/packages/flutter/lib/src/material/arc.dart:6:8: Error: Not found: 'dart:ui'
  import 'dart:ui' show lerpDouble;
         ^
  
  Process finished with exit code 254</code></pre>
  </div>
  </div>
  </p>
  <p>I have tried many ways to solve this issue but still, this issue is coming.</p>