Flutter_svg: Error using `precachePicture` with `null` context on `beta` and `dev` channels

[ifiokjr]

I'm seeing a similar error to this mentioned by @Nazacheres.

When using both the dev and beta channel of flutter. I haven't checked on stable yet.

Flutter 1.16.4-pre.86 • channel dev • https://github.com/flutter/flutter
Framework • revision a8b3d1b74f (3 days ago) • 2020-04-02 15:40:37 -0700
Engine • revision f56e678e7f
Tools • Dart 2.8.0 (build 2.8.0-dev.19.0 fae35fca47)

My dart code looks like this.

Future<void> main() async {
  await precachePicture(
    ExactAssetPicture(SvgPicture.svgStringDecoder, SvgAsset.logo.withText),
    null,
  );

  runApp(const SpinnyBoxApp());

  // Loads the local settings for the device.
  await SpinnyBoxSettings.loadSettings();
}

It crashes on the await precachePicture line with the following error log. _Click to expand the accordion._

Error Log

E/flutter (24782): Tried calling: dependOnInheritedWidgetOfExactType<DefaultAssetBundle>()
E/flutter (24782): #0      Object.noSuchMethod  (dart:core-patch/object_patch.dart:53:5)
E/flutter (24782): #1      DefaultAssetBundle.of 
package:flutter/…/widgets/basic.dart:5485
E/flutter (24782): #2      createLocalPictureConfiguration 
package:flutter_svg/src/picture_provider.dart:48
E/flutter (24782): #3      precachePicture 
package:flutter_svg/svg.dart:138
E/flutter (24782): #4      main 
package:spinny_box/main.dart:18
E/flutter (24782): #5      _runMainZoned.<anonymous closure>.<anonymous closure>  (dart:ui/hooks.dart:241:25)
E/flutter (24782): #6      _rootRun  (dart:async/zone.dart:1184:13)
E/flutter (24782): #7      _CustomZone.run  (dart:async/zone.dart:1077:19)
E/flutter (24782): #8      _runZoned  (dart:async/zone.dart:1619:10)
E/flutter (24782): #9      runZonedGuarded  (dart:async/zone.dart:1608:12)
E/flutter (24782): #10     _runMainZoned.<anonymous closure>  (dart:ui/hooks.dart:233:5)
E/flutter (24782): #11     _startIsolate.<anonymous closure>  (dart:isolate-patch/isolate_patch.dart:301:19)
E/flutter (24782): #12     _RawReceivePortImpl._handleMessage  (dart:isolate-patch/isolate_patch.dart:168:12)
E/flutter (24782):

239 is a similar issue, but since it's already been closed I thought it would be better to open a new one.

[dnfield]

Ahhh. Null won't work here.

precachePicture needs to be updated to handle this.

[dnfield]

Fixed in v0.17.4

[LiveLikeCounter]

@dnfield Awesome work, just what I needed!

One question: How can you load multiple assets-images at once?

Now, my main looks like this:

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  await precachePicture(
    ExactAssetPicture(SvgPicture.svgStringDecoder, 'assets/images/Welcome_carousel_1.svg'),
    null,
  );
  await precachePicture(
    ExactAssetPicture(SvgPicture.svgStringDecoder, 'assets/images/Welcome_carousel_2.svg'),
    null,
  );
  await precachePicture(
    ExactAssetPicture(SvgPicture.svgStringDecoder, 'assets/images/Welcome_carousel_3.svg'),
    null,
  );

  runApp(BrilliantButtonsApp());
}

Keep up the good work.

[dnfield]

That's basically it. You could refactor that into a method that just takes the strings I suppose

[ycherniavskyi]

For someone who doesn't like manually call precachePicture per asset:

  await Future.wait(
    [
      'assets/images/Welcome_carousel_1.svg',
      'assets/images/Welcome_carousel_2.svg',
      'assets/images/Welcome_carousel_3.svg',
    ].map(
      (assetName) => precachePicture(
        ExactAssetPicture(SvgPicture.svgStringDecoder, assetName),
        null,
      ),
    ),
  );