使用 PageView 进行页面切换的时候，通常需要更炫酷的方式，看下面的效果：

在滑出的时候当前页面逐渐缩小并居中，通过给PageController添加监听获取当前滑动的进度：

_pageController.addListener(() {
      setState(() {
        _currPageValue = _pageController.page;
      });
    });

通过当前的进度计算各个页面的缩放系数及平移系数，通过 判断当前构建的是哪个页面

if (index == _currPageValue.floor()) {
      //当前的item
      var currScale = 1 - (_currPageValue - index) * (1 - _scaleFactor);
     
    } else if (index == _currPageValue.floor() + 1) {
      //右边的item
      
    } else if (index == _currPageValue.floor() - 1) {
      //左边
      
    } else {
      //其他，不在屏幕显示的item
      
    }

通过对这几种类型的页面的缩放和平移达到我们想要的效果。

完整代码：

class ViewPage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _ViewPageState();
}

class _ViewPageState extends State<ViewPage> {
  var imgList = [
    'https://ss1.bdstatic.com/70cFvXSh_Q1YnxGkpoWK1HF6hhy/it/u=2877516247,37083492&fm=26&gp=0.jpg',
    'https://timgsa.demo.com/timg?image&quality=80&size=b9999_10000&sec=1582796218195&di=04ce93c4ac826e19067e71f916cec5d8&imgtype=0&src=http%3A%2F%2Fhbimg.b0.upaiyun.com%2F344fda8b47808261c946c81645bff489c008326f15140-koiNr3_fw658'
  ];
  PageController _pageController;

  var _currPageValue = 0.0;

  //缩放系数
  double _scaleFactor = .8;

  //view page height
  double _height = 230.0;

  @override
  void initState() {
    super.initState();
    _pageController = PageController(viewportFraction: 0.9);
    _pageController.addListener(() {
      setState(() {
        _currPageValue = _pageController.page;
      });
    });
  }

  @override
  void dispose() {
    super.dispose();
    _pageController.dispose();
  }
  @override
  Widget build(BuildContext context) {
    return Container(
        height: _height,
        child: PageView.builder(
          itemBuilder: (context, index) => _buildPageItem(index),
          itemCount: 10,
          controller: _pageController,
        ));
  }

  _buildPageItem(int index) {
    Matrix4 matrix4 = Matrix4.identity();
    if (index == _currPageValue.floor()) {
      //当前的item
      var currScale = 1 - (_currPageValue - index) * (1 - _scaleFactor);
      var currTrans = _height * (1 - currScale) / 2;

      matrix4 = Matrix4.diagonal3Values(1.0, currScale, 1.0)
        ..setTranslationRaw(0.0, currTrans, 0.0);
    } else if (index == _currPageValue.floor() + 1) {
      //右边的item
      var currScale =
          _scaleFactor + (_currPageValue - index + 1) * (1 - _scaleFactor);
      var currTrans = _height * (1 - currScale) / 2;

      matrix4 = Matrix4.diagonal3Values(1.0, currScale, 1.0)
        ..setTranslationRaw(0.0, currTrans, 0.0);
    } else if (index == _currPageValue.floor() - 1) {
      //左边
      var currScale = 1 - (_currPageValue - index) * (1 - _scaleFactor);
      var currTrans = _height * (1 - currScale) / 2;

      matrix4 = Matrix4.diagonal3Values(1.0, currScale, 1.0)
        ..setTranslationRaw(0.0, currTrans, 0.0);
    } else {
      //其他，不在屏幕显示的item
      matrix4 = Matrix4.diagonal3Values(1.0, _scaleFactor, 1.0)
        ..setTranslationRaw(0.0, _height * (1 - _scaleFactor) / 2, 0.0);
    }

    return Transform(
      transform: matrix4,
      child: Padding(
        padding: EdgeInsets.symmetric(horizontal: 10),
        child: Container(
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(12),
            image: DecorationImage(
                image: NetworkImage(imgList[index % 2]), fit: BoxFit.fill),
          ),
        ),
      ),
    );
  }
}