小编典典

Flutter:如何将变量从StatelessWidget传递到StatefulWidget

flutter

问题是我无法将我自己的类ForceSelection值从另一个屏幕传递到另一个屏幕的StatefulWidget。在StatelessWidget中工作正常。我试着从下面的教程中学习:https :
//flutter.dev/docs/cookbook/navigation/passing-data#4-navigate-and-pass-data-
to-the-detail-screen

我在levelSelection.dart中有此类

class ForceSelection {
  final String forceSelection;
  final String langSelection;

  ForceSelection(this.forceSelection, this.langSelection);
}

我正在尝试将值传递给下一个文件PlayQuiz.dart

Game(forceSelection: ForceSelection('maa', 'fin'))

game.dart看起来像这样:

class Game extends StatelessWidget {
  final ForceSelection forceSelection;

  Game({Key key, @required this.forceSelection}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: forceSelection.langSelection, // TODO should work and change later
      theme: new ThemeData(
        primaryColor: Colors.white,
      ),
      home: PlayQuiz(),
    );
  }
}

我想将ForceSelection值传递给PlayQuiz()

class PlayQuizState extends State<PlayQuiz> {
  Game.forceSelection // <--- How can I get the value out of here?
}

class PlayQuiz extends StatefulWidget {
  @override
  PlayQuizState createState() => new PlayQuizState(); 
}
整个代码可以在这里找到:https
://pastebin.com/nKssz42R以及levelSelection.dart:https
//pastebin.com/8QbBD0A2

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2020-08-13

共1个答案

小编典典

试试这个代码

在PlayQuiz()中添加了forceSelecton参数

class Game extends StatelessWidget {
final ForceSelection forceSelection;

Game({Key key, @required this.forceSelection}) : super(key: key);

@override
Widget build(BuildContext context) {
  return MaterialApp(
    title: forceSelection.langSelection, // TODO should work and change later
    theme: new ThemeData(
      primaryColor: Colors.white,
    ),
    home: PlayQuiz(forceSelection),
  );
 }
}

进行中测验

class PlayQuiz extends StatefulWidget {
  final ForceSelection forceSelection;

  PlayQuiz(this.forceSelection);

  @override
  PlayQuizState createState() => new PlayQuizState(forceSelection); 
}

在PlayQuizState

class PlayQuizState extends State<PlayQuiz> {
  ForceSelection forceSelection;

  PlayQuizState(ForceSelection forceSelection) {
    this.forceSelection = forceSelection;
  }
}
2020-08-13