Cannot run with sound null safety, because the following dependencies don‘t support
  解決辦法：終端執(zhí)行flutter run --no-sound-null-safety 或者在pubspec.yaml升級依賴版本到支持null-safety版本

Expected a key while parsing a block mapping.
pubspec.yaml里的assets 要對齊不要留空格，很無語的bug提示信息也很不友好
flutter:
  uses-material-design: true
  assets:
     - images/bg1.png

Flutter異常：
Could not find a generator for route RouteSettings("second_route", null) in the _WidgetsAppState.  注冊路由的路由名稱與你在pushname使用的路由名稱不匹配

[ERROR:flutter/lib/ui/ui_dart_state.cc(199)] Unhandled Exception: DioError [DioErrorType.DEFAULT]: type 'String' is not a subtype of type 'Map<String, dynamic>'
Retrofit自動生成的代碼改成如下所示，原因是后臺接口返回的Response的contentType是text/html而不是application/json，而這個接口是老接口后臺不好改動所以只能自己修改Retrofit自動生成的代碼_dio.fetch<T>的泛型T傳String 然后自己把String轉(zhuǎn)成json,再把json轉(zhuǎn)成對象返回
@override
  Future<BaseResponse<Object?>> requestCode(loginParam) async {
    const _extra = <String, dynamic>{};
    final queryParameters = <String, dynamic>{};
    final _headers = <String, dynamic>{};
    final _data = <String, dynamic>{};
    _data.addAll(loginParam);
    final _result = await _dio.fetch<String>(
        _setStreamType<BaseResponse<String?>>(
            Options(method: 'POST', headers: _headers, extra: _extra)
                .compose(_dio.options, 'securityCode/send',
                    queryParameters: queryParameters, data: _data)
                .copyWith(baseUrl: baseUrl ?? _dio.options.baseUrl)));
    final value = BaseResponse<Object?>.fromJson(
      jsonDecode(_result.data ?? ""),
      (json) => jsonEncode(json),
    );
    return value;
  }