blobs_duration_test

A basic Flutter project that tests a potential issue with the blobs Flutter Package.

When using Blob.animatedRandom, the duration of the animated blob seems to be stuck to the initial value, even if it is changed using setState in a StatefulWidget.

See the related issue in the flutter_blobs GitHub Repository.

Video of the issue

Here is the test app running on an Android 11.0 (API 30) emulator. Pressing the FAB button assigns a random duration and a random color. So the duration keeps changing (as reflected in the app bar), but the animation of the blob shape doesn't seem to change its rythm.

blobs_duration_test_2.mp4

The code

...

class _HomeScreenState extends State<HomeScreen> {
  final Random _random = Random();
  Color _color = Colors.blueGrey;

  // The duration of the animated blob seems to be stuck to this initial value,
  // even if we change it using setState.
  int _duration = 500;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Duration: $_duration milliseconds'), // display the current duration
      ),
      body: Blob.animatedRandom(
        size: 400,
        edgesCount: 6,
        minGrowth: 7,
        // Apply the current color - this works.
        styles: BlobStyles(color: _color),
        loop: true,
        // Apply the current duration - doesn't seem to work!
        duration: Duration(milliseconds: _duration),
      ),
      floatingActionButton: FloatingActionButton(
        child: const Icon(Icons.shuffle),
        onPressed: () => setState(() {
          // Randomize the duration and the color
          _duration = _random.nextInt(20) * 500;
          _color = Color.fromRGBO(_random.nextInt(256), _random.nextInt(256), _random.nextInt(256), 1.0);
        }),
      ),
    );
  }
}

(See the full code).