有没有办法在bottomsheet中验证Textfield？

final _formKey = GlobalKey<FormState>();

showModalBottomSheet(
  context: context,
  builder: (BuildContext context) {
    return Container(
      padding: EdgeInsets.all(20.0),
      child: Form(
        key: _formKey,
        child: Column(
          children: <Widget>[
            TextFormField(
              validator: (value) {
                if (value.isEmpty) {
                  return '请输入内容';
                }
                return null;
              },
              decoration: InputDecoration(
                labelText: '文本框',
              ),
            ),
            RaisedButton(
              onPressed: () {
                if (_formKey.currentState.validate()) {
                  // 验证通过，执行其他操作
                }
              },
              child: Text('提交'),
            ),
          ],
        ),
      ),
    );
  },
);