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我想在我的 SliverAppBar 中垂直居中标题。我在互联网上找到了一个解决方案,您将空容器放在标题上方和下方,以便文本居中,但问题是当您向上滚动并且只有小应用栏时,您看不到更多标题,因为空容器太大。我已经将我的标题水平居中,但我也需要它垂直居中。有谁知道这个问题的解决方案?

这是我目前的代码:

SliverAppBar(
    expandedHeight: MediaQuery.of(context).size.height * 0.20,
    floating: false,
    pinned: true,
    flexibleSpace: FlexibleSpaceBar(
      centerTitle: true,
      title: Text("Training"),
      background: Image.asset(
        "assets/purpleBackground.png",
        fit: BoxFit.cover,
      ),
    ),
  ),
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1 回答 1

3

这是一种可能的方法:

 @override
  Widget build(BuildContext context) {
    double height = MediaQuery.of(context).size.height;
    return Scaffold(
      body: CustomScrollView(
        slivers: <Widget>[
          SliverAppBar(
            pinned: true,
            expandedHeight: height * 0.2,
            collapsedHeight: height * 0.075,
            flexibleSpace: LayoutBuilder(
              builder: (context, constraints) {
                double appBarHeight = constraints.biggest.height; //getting AppBar height
                bool isExpanded = appBarHeight > height * 0.2; //check if AppBar is expanded
                return FlexibleSpaceBar(
                  titlePadding: EdgeInsets.zero,
                  centerTitle: true,
                  title: SizedBox(
                    height: height * 0.15,
                    child: Column(
                      mainAxisAlignment: isExpanded
                          ? MainAxisAlignment.center
                          : MainAxisAlignment.end,
                      children: <Widget>[
                        Container(
                          padding:
                              isExpanded ? EdgeInsets.zero : EdgeInsets.all(20),
                          child: Text(
                            "Training",
                          ),
                        ),
                      ],
                    ),
                  ),
                );
              },
            ),
          ),
          SliverList(
            delegate: SliverChildListDelegate.fixed(
              List.generate(
                50,
                (index) => ListTile(
                  title: Text('Index $index'),
                ),
              ),
            ),
          ),
        ],
      ),
    );
 

输出 :

在此处输入图像描述

于 2021-02-12T16:16:07.117 回答