每日tips：FocusScopeNode移动焦点你用对了吗？

class EmailPasswordSignInForm extends StatefulWidget {
  @override
  _EmailPasswordSignInFormState createState() =>
      _EmailPasswordSignInFormState();
}

class _EmailPasswordSignInFormState extends State<EmailPasswordSignInForm> {
  final FocusScopeNode _node = FocusScopeNode();
  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();

  @override
  void dispose() {
    _node.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Form(
      key: _formKey,
      child: FocusScope(
        node: _node,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: <Widget>[
            // email
            TextFormField(
              decoration: InputDecoration(
                labelText: 'Email',
                hintText: 'john@doe.com',
              ),
              textInputAction: TextInputAction.next,
              keyboardType: TextInputType.emailAddress,
              // move to the next field
              onEditingComplete: _node.nextFocus,
            ),
            // password
            TextFormField(
              decoration: InputDecoration(
                labelText: 'Password',
              ),
              obscureText: true,
              textInputAction: TextInputAction.done,
              // move to the next field
              onEditingComplete: _node.nextFocus,
            ),
            // submit
            RaisedButton(
              child: Text('Sign In'),
              onPressed: () {/* submit code here */},
            ),
          ],
        ),
      ),
    );
  }
}