Flutter控制某个TextField获取焦点及失去焦点

FocusNode _commentFocus = FocusNode();

TextField(
  focusNode: _commentFocus,
),

FocusScope.of(context).requestFocus(_commentFocus);     // 获取焦点

_commentFocus.unfocus();    // 失去焦点

import ‘package:flutter/material.dart‘;

class CommentTest extends StatefulWidget {
  @override
  _CommentTestState createState() => _CommentTestState();
}

class _CommentTestState extends State<CommentTest> {

  TextEditingController _textEditingController = TextEditingController();
  String _currentTipsText = "有爱评论，说点儿好听的~";
  FocusNode _commentFocus = FocusNode();
  List<Map> _commentList = [
    {
      ‘name‘: ‘涂山雏雏‘,
      ‘headerImg‘: ‘http://i2.hdslb.com/bfs/face/cab3e9ec886ff98bc7ac6cb2dca194051895dfba.jpg@52w_52h.webp‘,
      ‘content‘: ‘你以为我是红细胞，其实我是兵库北哒(｀?ω?´)~‘
    },
    {
      ‘name‘: ‘漆黑的魂焰魔法使‘,
      ‘headerImg‘: ‘http://i0.hdslb.com/bfs/face/6edd973203eb1ec2b576a3bc61ee555e3757b674.jpg@52w_52h.webp‘,
      ‘content‘: ‘你说我的头发怎么了啊，啊!‘
    },
    {
      ‘name‘: ‘汐华初流艿‘,
      ‘headerImg‘: ‘http://i0.hdslb.com/bfs/face/ecf4c932d4f09ffdcd769b423764210488d03209.jpg@52w_52h.webp‘,
      ‘content‘: ‘你们因为你们身体里面真的有萌妹子吗，其实全都是dio哒‘
    }
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(‘点击留言输入框获取焦点‘,style: TextStyle(color: Colors.white,fontSize: 20),),
      ),
      body: Stack(
        children: <Widget>[
          ListView.builder(
            itemCount: _commentList.length,
            itemBuilder: (context,index){
              return ListTile(
                leading: ClipRRect(borderRadius: BorderRadius.circular(20),child: Image.network(_commentList[index][‘headerImg‘],width: 40,height: 40,),),
                title: Text(_commentList[index][‘name‘]),
                subtitle: Text(_commentList[index][‘content‘]),
                onTap: (){
                  _switchReply(_commentList[index][‘name‘]);
                },
              );
            },
          ),
          Positioned(
            left: 0,
            bottom: 0,
            child: Container(
              width: MediaQuery.of(context).size.width,
              color: Color.fromRGBO(222, 222, 222, 1),
              height: 50,
              child: Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                crossAxisAlignment: CrossAxisAlignment.center,
                children: <Widget>[
                  Expanded(
                    child: TextField(
                      controller: _textEditingController,
                      focusNode: _commentFocus,
                      decoration: InputDecoration(
                        hintText: _currentTipsText,
                        contentPadding: EdgeInsets.only(left: 10,top: 17,bottom: 17),
                      ),
                    ),
                  ),
                  InkWell(
                    child: Container(
                      width: 50,
                      height: 50,
                      alignment: Alignment.center,
                      child: Icon(Icons.near_me,size: 25.5,color: Color.fromRGBO(50, 50, 50, 1)),
                    ),
                    onTap: (){
                      _sendMessage();
                    },
                  ),
                ],
              ),
            ),
          ),
        ],
      )
    );
  }

  // 发送回复评论
  void _sendMessage() {
    _commentList.add({
      ‘name‘: ‘爱吃汉堡包的天残‘,
      ‘headerImg‘: ‘http://i1.hdslb.com/bfs/face/1cb09a8cfec19bd06fbbeba5b978c1ee52a62d3f.jpg@52w_52h.webp‘,
      ‘content‘: _textEditingController.text
    });
    _currentTipsText = "有爱评论，说点儿好听的~";
    _textEditingController.text = ‘‘;
    _commentFocus.unfocus();    // 失去焦点
  }

  // 获取焦点拉起键盘
  void _switchReply(nickname) {
    setState(() {
      _currentTipsText = ‘回复 ‘+nickname+‘:‘;
    });
    FocusScope.of(context).requestFocus(_commentFocus);     // 获取焦点
  }

}