Multiple calls to ExprollablePageController.animateViewportOffsetTo during the animation can cause it to become stuck.

[khoadng]

Video:

Screen.Recording.2023-05-04.at.22.40.56.mov

import 'package:example/src/common.dart';
import 'package:exprollable_page_view/exprollable_page_view.dart';
import 'package:flutter/material.dart';

class SimpleExample extends StatefulWidget {
  const SimpleExample({super.key});

  @override
  State<SimpleExample> createState() => _SimpleExampleState();
}

class _SimpleExampleState extends State<SimpleExample> {
  late final controller = ExprollablePageController(
    initialPage: 0,
    maxViewportOffset: ViewportOffset.shrunk,
    minViewportFraction: 0.8,
    snapViewportOffsets: [
      ViewportOffset.expanded,
      ViewportOffset.shrunk,
    ],
  );
  var expanded = false;
  var title = "";

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(title),
        actions: [
          if (expanded)
            IconButton(
                onPressed: () {
                  setState(() {
                    title = "animate to shrunk";
                  });
                  controller.animateViewportOffsetTo(ViewportOffset.shrunk,
                      curve: Curves.easeOut,
                      duration: Duration(milliseconds: 150));
                },
                icon: Icon(Icons.keyboard_double_arrow_up))
          else
            IconButton(
                onPressed: () {
                  setState(() {
                    title = "animate to expanded";
                  });
                  controller.animateViewportOffsetTo(ViewportOffset.expanded,
                      curve: Curves.easeOut,
                      duration: Duration(milliseconds: 150));
                },
                icon: Icon(Icons.keyboard_double_arrow_down))
        ],
      ),
      bottomNavigationBar: const ExampleBottomAppBar(),
      body: ExprollablePageView(
        onViewportChanged: (metrics) => setState(() {
          expanded = metrics.isExpanded;
        }),
        controller: controller,
        itemCount: 5,
        itemBuilder: (context, page) {
          return ExampleListView(
            controller: PageContentScrollController.of(context),
            page: page,
          );
        },
      ),
    );
  }
}

[fujidaiti]

Seems like a bug related to floating point precision. I'll work on it.