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我正在使用PageView.builder并在检测到来自_scrollController的滚动后逐渐增加viewportFraction 。演示相同的视频

当我们向下滚动时，我希望左右屏幕元素以更平滑的方式消失。在这里，当我逐渐改变视口时，文本正在重新对齐，这看起来很糟糕，左右屏幕内容失焦的方式会突然扩大。我希望这是一个平滑的过渡/动画。

知道如何实现这一目标吗？或者有什么更好的方法来实现这一点？

这是带有 PageController 的PageView.builder：

class CarouselHolder extends StatefulWidget {
  const CarouselHolder({Key? key}) : super(key: key);

  @override
  _CarouselHolderState createState() => _CarouselHolderState();
}

class _CarouselHolderState extends State<CarouselHolder> {
  int currentPage = 0;

  double factor = 0.90;

  bool fullScreen = false;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SafeArea(
          child: Stack(
        children: [
          PageView.builder(
            itemBuilder: (context, i) {
              return Opacity(
                opacity: currentPage == i ? 1.0 : 0.8,
                child: DetailViewScreen(
                  onViewPortFactorChanged: (double val) {
                    setState(() {
                      // fullScreen = val == 1.0 ? true : false;
                      factor = val;
                    });
                  },
                ),
              );
            },
            itemCount: data.length,
            controller:
                PageController(initialPage: 0, viewportFraction: factor),
            onPageChanged: (i) {
              setState(() {
                factor = 0.90;
                currentPage = i;
              });
            },
          ),
        ],
      )),
    );
  }
}

在这里，检测到滚动并逐渐增加视口

import 'package:flutter/material.dart';

class DetailViewScreen extends StatefulWidget {
  const DetailViewScreen({
    Key? key,
    this.onViewPortFactorChanged,
  }) : super(key: key);

  final Function(double)? onViewPortFactorChanged;

  @override
  State<DetailViewScreen> createState() => _DetailViewScreenState();
}

class _DetailViewScreenState extends State<DetailViewScreen> {
  ScrollController? _scrollController;

  _scrollListener() {
    for (int i = 1; i <= 20; i++) {
      if (_scrollController!.offset >= i * 20 &&
          _scrollController!.offset < 401.0) {
        widget.onViewPortFactorChanged!(0.90 + (i / 200));
      }
    }
  }

  @override
  void initState() {
    super.initState();
    _scrollController = ScrollController();
    _scrollController!.addListener(_scrollListener);
  }

  @override
  void dispose() {
    _scrollController!.dispose();
    // _controller!.removeListener(_scrollListener);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      controller: _scrollController,
      child: detailViewScreenContent(),
    );
  }

  Widget detailViewScreenContent() {
    const verticalDividerSpace = SizedBox(height: 24);
    const String text =
        'Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum';

    return Padding(
      padding: const EdgeInsets.all(8.0),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Container(
            height: 400,
            color: Colors.yellow,
          ),
          verticalDividerSpace,
          const Text(text),
          verticalDividerSpace,
          Container(height: 300, color: Colors.pinkAccent),
          verticalDividerSpace,
          Container(
            height: 400,
            color: Colors.amberAccent,
          ),
          verticalDividerSpace,
          Container(
            height: 400,
            color: Colors.greenAccent,
          )
        ],
      ),
    );
  }
}
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