小编Raj*_*A V的帖子

只是在探索颤振并被卡住了。prefixIcon 在单击字段上消失，当聚焦时它会出现。如何解决这个问题？代码如下。尝试删除表单的键。我希望图标即使聚焦或聚焦也能保持不变。还有其他属性要设置吗？无法找到修复方法。

        class _MyHomePageState extends State<MyHomePage> {
          String _email = "";
          String _password = "";

          final  _formKey = GlobalKey<FormState>();
          final FocusNode _emailFocus = FocusNode();
          final FocusNode _passwordFocus = FocusNode();



          @override
          Widget build(BuildContext context) {
            return Scaffold(
              appBar: AppBar(
                title: Text(widget.title),
              ),
              body: Container(
                      padding: const EdgeInsets.symmetric(horizontal: 50.0,vertical: 100.0),
                      decoration: BoxDecoration(color: Colors.white),
                      child:Form(
                        key: _formKey,
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: <Widget>[
                            TextFormField(
                              focusNode: _emailFocus,
                                decoration: InputDecoration(
                                    labelText: 'Username or email',
                                    prefixIcon: Icon(Icons.person), //prefixIcon
                                  focusedBorder: UnderlineInputBorder(),
                                  hintText: "example@mail.com",
                                )
                            ),
                            Padding(
                              padding: …