在appbar更改抽屉的菜单图标

Question

如果您创建Scafold,则可以选择抽屉.如果您现在创建此抽屉,则会自动获得应用栏前导位置上的菜单图标.但我想在那里打开抽屉的另一个图标.我尝试在领先位置自己制作一个iconbutton但是这个按钮无法打开抽屉,即使是"Scafold.of(context).openDrawer()"也无法打开它.

是否有任何选项可以替换抽屉按钮的图标？

Answer 1

使用Key你的,Scaffold并通过调用显示抽屉myKey.currentState.openDrawer(),这是一个工作代码:

import "package:flutter/material.dart";

class Test extends StatefulWidget {
  @override
  _TestState createState() => new _TestState();
}

class _TestState extends State<Test> {
  final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      key: _scaffoldKey,
      drawer: new Drawer(),
      appBar: new AppBar(
        leading: new IconButton(icon: new Icon(Icons.settings),
            onPressed: () => _scaffoldKey.currentState.openDrawer()),
      ),
    );
  }
}

Answer 2

替代接受的答案,不需要GlobalKey:

class _TestState extends State<Test> {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      drawer: new Drawer(),
      appBar: new AppBar(
        leading: Builder(
            builder: (context) => IconButton(
                  icon: new Icon(Icons.settings),
                  onPressed: () => Scaffold.of(context).openDrawer(),
                ),
        ),
      ),
    );
  }
}

Answer 3

使用全局密钥：

final GlobalKey<ScaffoldState> _key = GlobalKey(); // Create a key

@override
Widget build(BuildContext context) {
  return Scaffold(
    key: _key, // Assign the key to Scaffold.
    drawer: Drawer(),
    floatingActionButton: FloatingActionButton(
      onPressed: () => _key.currentState!.openDrawer(), // <-- Opens drawer
    ),
  );
}

使用生成器：

@override
Widget build(BuildContext context) {
  return Scaffold(
    drawer: Drawer(),
    floatingActionButton: Builder(builder: (context) {
      return FloatingActionButton(
        onPressed: () => Scaffold.of(context).openDrawer(), // <-- Opens drawer.
      );
    }),
  );
}

Answer 4

之后你需要初始化scaffoldKey ，

打开抽屉和关闭抽屉

 GestureDetector(
          onTap: () {
            if(scaffoldKey.currentState.isDrawerOpen){
              scaffoldKey.currentState.openEndDrawer();
            }else{
              scaffoldKey.currentState.openDrawer();
            }
          },
          child:  LeadingIcon(icon: Icons.menu),//your button
        ),