将继承的小部件更改为有状态不起作用

Question

所以我有一个小部件，我想让它有状态，这样我就可以向图像添加动画。然而，这个小部件从另一个类继承了最终变量，当我使它有状态时，它就会停止正常工作。如有任何帮助，我们将不胜感激。

最后一类：

class Result extends GetPicture {
Result(int resultScore, Function resetHandler)     //Here's the inherited values
: super(resetHandler, resultScore);
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.black87,
body: ListView(
children: <Widget>[
GetPicture(resetHandler, resultScore),
Align(
alignment: Alignment.center,
child: RaisedButton(
child: Text(
'Restart Quiz!',
style: TextStyle(fontSize: 20),
),
textColor: Colors.blue,
onPressed: resetHandler,
),
)
],
),
);
}
}

这是它继承自的类：

// i want to make this stateful:
class GetPicture extends StatelessWidget {
final int resultScore;
final Function resetHandler;
GetPicture(this.resetHandler, this.resultScore);
@override
Widget build(BuildContext context) {
AlignmentDirectional _standAlignment = AlignmentDirectional(0.0, 0.7);
Widget child;
if (resultScore <= 5) {
child = Container(
margin: EdgeInsets.only(top: 10),
child: Column(children: <Widget>[
Container(
child: Text(
'You Got Star Platinum!',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 30,
color: Colors.white54),
),
),
AnimatedContainer(
duration: Duration(milliseconds: 500),
alignment: _standAlignment,
child: Image.asset('assets/images/stands/star platinum.jpg',
height: 300, width: 200),
),
Container(
margin: EdgeInsets.only(right: 20, left: 20, bottom: 50),
child: Text(
'Star Platinum is a close-range Stand, with a basic reach of only 2 meters from Jotaros 
body, but with incredible strength, speed, and precision. It is one of the most powerful Stands 
featured in the series.',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 20,
color: Colors.white54),
))
]));
} else if (resultScore > 5 && resultScore <= 10) {
child = Container(
margin: EdgeInsets.only(top: 10),
child: Column(children: <Widget>[
Container(
child: Text(
'You Got Hierophant Green!',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 30,
color: Colors.white54),
),
),
Image.asset('assets/images/stands/H-green.jpg',
height: 300, width: 200),
Container(
margin: EdgeInsets.only(right: 20, left: 20, bottom: 50),
child: Text(
'H-green is a close-range Stand, with a basic reach of only 2 meters from Jotaros body, but with incredible strength, speed, and precision. It is one of the most powerful Stands featured in the series.',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 20,
color: Colors.white54),
))
]));
}
return new Container(child: child);
}
}

这是它从中获得最终值的类：

import './quiz.dart';
import './result.dart';

void main() => runApp(QuizPage());
class QuizPage extends StatefulWidget {
@override
State<StatefulWidget> createState() {
// TODO: implement createState
return _MyAppState();
}
}
class _MyAppState extends State<QuizPage> {
var _questionIndex = 0;
var _totalScore = 0;
final _questions = const [
{
'questionText': 'Which would Describe you best?',
'answers': [
{'text': 'Brash', 'score': 0},
{'text': 'Confident', 'score': 1},
{'text': 'Timid', 'score': 2},
{'text': 'Nice', 'score': 3}
]
},
{
'questionText': 'Which's mother toung of India?',
'answers': [
{'text': 'Marathi', 'score': 0},
{'text': 'Gujarati', 'score': 1},
{'text': 'Tamil', 'score': 2},
{'text': 'Hindi', 'score': 3}
]
},
{
'questionText': 'Who's prime ministor of India?',
'answers': [
{'text': 'Narendra Modi', 'score': 0},
{'text': 'Amit Shah', 'score': 1},
{'text': 'Sonia Gandhi', 'score': 2},
{'text': 'Rahul Gandhi', 'score': 3}
]
},
{
'questionText': 'Who's president of India?',
'answers': [
{'text': 'Lalkrishna Advani', 'score': 0},
{'text': 'Barak Obama', 'score': 1},
{'text': 'Ramnath Kovind', 'score': 2},
{'text': 'Pratibha Patil', 'score': 3}
]
},
{
'questionText': 'Who's Chief Minister of Gujarat?',
'answers': [
{'text': 'Nitin Patel', 'score': 0},
{'text': 'Vijay Rupani', 'score': 1},
{'text': 'Jayesh Radadiya', 'score': 2},
{'text': 'Paresh Dhanani', 'score': 3}
]
},
{
'questionText':
'Which of the following was the author of the Arthashastra?',
'answers': [
{'text': 'Kalhan', 'score': 0},
{'text': 'Visakhadatta', 'score': 1},
{'text': 'Bana Bhatta', 'score': 2},
{'text': 'Chanakya', 'score': 3}
]
},
];
void _resetQuiz() {
setState(() {
_questionIndex = 0;
_totalScore = 0;
});
}
void _answerQuestions(int score) {
_totalScore += score;
setState(() {
_questionIndex = _questionIndex + 1;
});
print('_questionIndex:$_questionIndex');
}
@override
Widget build(BuildContext context) {
// TODO: implement build
return MaterialApp(
home: Scaffold(
appBar: GradientAppBar(
gradient: LinearGradient(
begin: Alignment.topLeft,
end: Alignment.bottomRight,
colors: <Color>[Colors.blue, Colors.black]),
title: Text('Quiz App'),
),
body: _questionIndex < _questions.length
? Quiz(
questions: _questions,
answerQuestions: _answerQuestions,
questionIndex: _questionIndex)
: Result(_totalScore, _resetQuiz),
),
);
}
}

Answer 1

您可以这样使用有状态的小部件：

class Hello extends StatefulWidget {
final hello;
//final declared here
const Hello({Key key, this.hello}) : super(key: key);
@override
_HelloState createState() => _HelloState();
}
class _HelloState extends State<Hello> {
@override
Widget build(BuildContext context) {
return Container(
height: widget.hello, //called here
);
}
}

也就是说，你可以有最终值，然后你可以使用widget.variablename调用它们，它将工作