Flutter-如何更改AppBar高度并对齐标题垂直中心？

Question

我需要在Flutter应用中更改应用栏的高度。我使用此代码：

 Widget build(BuildContext context) {
 return Scaffold(
    appBar: PreferredSize(
      preferredSize: Size.fromHeight(100.0),
      child: AppBar(
        automaticallyImplyLeading: false, 
        flexibleSpace: Container(),
        centerTitle: true,
        title: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: <Widget>[
            Icon(Icons.search),
            Icon(Icons.home),
            PopupMenuButton<String>(
              icon: Icon(Icons.menu),
                itemBuilder: (BuildContext context) => <PopupMenuEntry<String>>[
                  PopupMenuItem<String>(
                    value: "1",
                    child: Text('Hello'),
                  ),
                  PopupMenuItem<String>(
                    value: "2",
                    child: Text('World'),
                  ),
                ]
            )
          ],
        ),
      ),
    ),
    body: Container());
}

这是我的结果：

高度已更改，但我需要将内容垂直居中对齐。我尝试了此选项，但它不起作用：

        automaticallyImplyLeading: false, 
        flexibleSpace: Container(),
        centerTitle: true,

任何建议？

Answer 1

尝试一下

Widget build(BuildContext context) {
 return Scaffold(
    appBar: PreferredSize(
      preferredSize: Size.fromHeight(100.0),
      child: AppBar(
        automaticallyImplyLeading: false, 
        flexibleSpace: Container(),
        centerTitle: true,
        title: Row(
          crossAxisAlignment:CrossAxisAlignment.center
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: <Widget>[
            Icon(Icons.search),
            Icon(Icons.home),
            PopupMenuButton<String>(
              icon: Icon(Icons.menu),
                itemBuilder: (BuildContext context) => <PopupMenuEntry<String>>[
                  PopupMenuItem<String>(
                    value: "1",
                    child: Text('Hello'),
                  ),
                  PopupMenuItem<String>(
                    value: "2",
                    child: Text('World'),
                  ),
                ]
            )
          ],
        ),
      ),
    ),
    body: Container());
}