Flutter 在单击某个位置之前，颤振typeahead不会显示建议

我在我的flatterweb项目中使用了flatter-typeahead包。 问题是，当用户在文本字段中键入程序包时，直到单击页面上的某个地方，程序包才显示任何建议，然后显示。 这是我的密码：

Container(
            height: 45,
            width: 250,
            decoration: searchBoxDecoration,
            child: TypeAheadField(
              noItemsFoundBuilder: (BuildContext context) {
                return Container(
                  width: 250,
                  height: 60,
                  child: Center(
                    child: Text(
                      'loading..',
                      style: TextStyle(color: Colors.black54),
                      textAlign: TextAlign.center,
                    ),
                  ),
                );
              },
              loadingBuilder: (BuildContext context) {
                return Container(
                  width: 250,
                  height: 60,
                  child: Center(
                    child: Text(
                      'loading..',
                      style: TextStyle(fontSize: 12.5),
                    ),
                  ),
                );
              },
              errorBuilder: (BuildContext context, Object error) =>
                  Container(width: 0, height: 0),
              textFieldConfiguration: TextFieldConfiguration(
                  scrollPadding: EdgeInsets.all(10),
                  textDirection: TextDirection.rtl,
                  maxLines: 1,
                  style: TextStyle(fontSize: 12.5),
                  decoration: searchFieldDecoration,
                  controller: this._typeAheadController),
              suggestionsCallback: (pattern) async {
                return await getSuggestions(pattern);
              },
              itemBuilder: (context, suggestion) {
                return Padding(
                  padding: EdgeInsets.symmetric(vertical: 9.0),
                  child: Center(
                      child: Text(
                    suggestion['major'],
                    textDirection: TextDirection.rtl,
                    textAlign: TextAlign.center,
                  )),
                );
              },
              onSuggestionSelected: (suggestion) {
                this._typeAheadController.text = suggestion['major'];
                setState(() {
                  majorSearchFieldValue = suggestion['major'];
                  majorId = suggestion['id'];
                });
              },
            )),

我的建议是：

  Future<List> getSuggestions(String query) async {
await Future.delayed(Duration(milliseconds: 300));
http.Response response = await http.get('${Config.url}/major/title/$query');
if (response.statusCode == 200) {
  var jsonToData = jsonDecode(response.body);
  setState(() {
    List data = jsonToData["majors"];
    for (int i = 0; i < data.length; i++) {
      majorsId.add(data[i]["id"]);
      majors.add(data[i]["title"]);
    }
  });
  return List.generate(5, (index) {
    return {'major': majors[index], 'id': majorsId[index]};
  });
} else {
  throw Exception('Something went wrong');
}

Future-getSuggestions（字符串查询）异步{
等待未来。延迟（持续时间（毫秒：300））；
http.Response-Response=wait http.get（'${Config.url}/major/title/$query'）；
如果（response.statusCode==200）{
var jsonToData=jsonDecode（response.body）；
设置状态（）{
列表数据=jsonToData[“专业”]；
对于（int i=0；i

} 这个问题不存在，但当我得到一个新的建设，它显示出来