Question

我正在尝试通过Flutter中的构造函数传递参数。当我在新页面上收到参数时，它为null。

我尝试更改

发送参数musicPlayerModel：

Align(
  alignment: Alignment.bottomRight,
  child: FlatButton(
    child: Text('Settings'),
    onPressed: () {
      Navigator.push(
        context,
        MaterialPageRoute(
          builder: (context) => SettingPage(musicPlayerModel: _musicPlayer,),
        ),
      );
    },
  ),
)

检索它，它为null：

class SettingPage extends StatefulWidget {
  SettingPage({@required this.musicPlayerModel});

  final MusicPlayerModel musicPlayerModel;
  UserApi _userApi = UserApi();
  UserModel _userModel = UserModel();

  _SettingPageState createState() =>
      _SettingPageState(musicPlayerModel, _userModel, _userApi);
}

_musicPlayer在第一页的开头实例化。我还使用调试工具检查了该值是否不为空。

class _MainPageState extends State<MainPage> {
  User user;

  _MainPageState(userInfo) {
    this.user = User(userInfo);
    _musicPlayer = MusicPlayerModel(user);
  }

在创建新页面方面，我可能缺少一些基本知识吗？

Answer 1

尝试在MaterialPageRoute之外创建页面

Align(
  alignment: Alignment.bottomRight,
  child: FlatButton(
    child: Text('Settings'),
    onPressed: () {
    final page = SettingPage(musicPlayerModel: _musicPlayer);
      Navigator.push(
        context,
        MaterialPageRoute(
          builder: (context) => page,
        ),
      );
    },
  ),
)

将数据传递到小部件构造函数为null

1 个答案: