您可以使用自定义高度创建自己的自定义小部件：

import "package:flutter/material.dart";

class Page extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Column(children : <Widget>[new CustomAppBar("Custom App Bar"),new Container()],);
  }
}


class CustomAppBar extends StatelessWidget {

  final String title;
  final double barHeight = 50.0; // change this for different heights 

  CustomAppBar(this.title);

  @override
  Widget build(BuildContext context) {
    final double statusbarHeight = MediaQuery
        .of(context)
        .padding
        .top;

    return new Container(
      padding: new EdgeInsets.only(top: statusbarHeight),height: statusbarHeight + barHeight,child: new Center(
        child: new Text(
          title,style: new TextStyle(fontSize: 20.0,fontWeight: FontWeight.bold),),);
  }
}