• 将leading设置为null
• 将automaticallyImplyLeading设置为false

看看automaticallyImplyLeading的说明：

Controls whether we should try to imply the leading widget if null.
If true and [AppBar.leading] is null, automatically try to deduce what the leading widget should be. If false and [AppBar.leading] is null, leading space is given to [AppBar.title]. If leading widget is not null, this parameter has no effect.

意思就是说：

• 如果leading为null 并且 automaticallyImplyLeading为true ， 那么会保留leading的占位位置；
• 如果如果leading为null 并且automaticallyImplyLeading为false ， 那么会将leading的位置让给title；
• 如果leading不为null ， automaticallyImplyLeading这个设置失效。

代码如下：

@override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
      	
        leading: null,
        automaticallyImplyLeading: false,
        title: Container(
            margin: EdgeInsets.fromLTRB(0, 0, 0, 0), 
            height: Screenadapter.height(100),
            width:  Screenadapter.width(880) ,
            decoration: BoxDecoration(
              borderRadius: BorderRadius.circular(20),
              color: Color.fromARGB(10, 0, 0, 0)
            ),
            child: Row(
              crossAxisAlignment: CrossAxisAlignment.center,
              children: [
                Padding(padding: EdgeInsets.fromLTRB(10, 0, 0, 0), child: Icon(Icons.search, color: Colors.black26)),
                Expanded(child: Text("耳机", style: TextStyle(color: Colors.black45, fontSize: Screenadapter.fontSize(36)))),
                Padding(padding: EdgeInsets.fromLTRB(0, 0, 10, 0), child: Icon(FangXMIcon.saomiao, color: Colors.black26)),
              ],
            ),
          ),
        centerTitle: true,
        actions: [
          Container(
            padding: EdgeInsets.fromLTRB(0, 0, 0, 0),
            width: Screenadapter.width(124),
            height: Screenadapter.height(100),
            child: InkWell(
              child: Icon(FangXMIcon.xiaoxi, color: Colors.black54 ),
            ),
          )
        ],
      ),
      body: const Center(
        child: Text(
          'GiveView is working',
          style: TextStyle(fontSize: 20),
        ),
      ),
    );
  }

效果如下：