将SafeArea添加到SliverAppBar

本文介绍了将SafeArea添加到SliverAppBar的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

如何使SliverAppBar中的FlexibleSpaceBar遵守SafeArea？

How to make FlexibleSpaceBar in SliverAppBar honour SafeArea?.

CustomScrollView(
        slivers: <Widget>[
          SliverAppBar(
            pinned: true,
            expandedHeight: 200,
            flexibleSpace: FlexibleSpaceBar(
              collapseMode: CollapseMode.pin,
              title: FittedBox(
                  fit: BoxFit.fitWidth,
                  child: Image.asset('assets/images/user.png')),
            ),
          ),
          SliverList(
            delegate: SliverChildListDelegate([
              TextField(),
            ]),
          )
        ],
      )

我需要图像始终在os头下

I need the image be below os header at all time

我试图用SafeArea小部件包装它，但是没有用，并且崩溃了d

I tried to wrap it with SafeArea widget but that didn't work and crashed

推荐答案

以下方法应该起作用：

class TestSafeArea extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomScrollView(
        slivers: <Widget>[
          SliverPersistentHeader(
              pinned: true,
              delegate: SafeAreaPersistentHeaderDelegate(
                  expandedHeight: 200,
                  child: Image.asset('assets/YOUR_IMAGE.png'))),
          SliverList(
            delegate: SliverChildListDelegate([
              TextField(),
            ]),
          )
        ],
      ),
    );
  }
}

class SafeAreaPersistentHeaderDelegate extends SliverPersistentHeaderDelegate {
  final Widget child;

  final double expandedHeight;

  SafeAreaPersistentHeaderDelegate({this.child, this.expandedHeight});

  @override
  Widget build(
      BuildContext context, double shrinkOffset, bool overlapsContent) {
    return SafeArea(bottom: false, child: SizedBox.expand(child: child));
  }

  @override
  double get maxExtent => expandedHeight;

  @override
  double get minExtent => kToolbarHeight;

  @override
  bool shouldRebuild(SafeAreaPersistentHeaderDelegate old) {
    if (old.child != child) {
      return true;
    }
    return false;
  }
}

很抱歉造成混乱！

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