Question

1/ 我对这段代码有问题，但 3 天后我仍然不明白为什么。请参阅图片以更好地了解软件给我的错误（错误使用 ParentDataWidget 错误）。 Error code in Android Studio program

2/ 然后我有另一个关于初始化的问题：到 void Initstate 中，变量visualedText 不能用函数 getTranslated 翻译（它不接受上下文）。出于什么原因？

class WarmUpPage extends StatefulWidget {
  WarmUpPage({Key key}) : super(key: key);
  @override
  _WarmUpPageState createState() => _WarmUpPageState();
}

class _WarmUpPageState extends State<WarmUpPage> {
  int counter = 8;
  dynamic visualizedText; //text to be visualized above button
  Image imgButton;
  Image imgButtonUp = Image.asset("lib/images/unpressed.png");
  Image imgButtonDown = Image.asset("lib/images/pressed.png");

  //Inizialize the state of the picture into imgButtonUp
  void initState() {
    super.initState();
    imgButton = imgButtonUp;
    visualizedText ='Warm Up'; //initial text but I cannot translate it because context gives error
  }

  //Function to increment the counter
  void _decrementCounter() {
    setState(() {
      counter--;
      if (counter == 0) {
        randompagegenerator(context);
      } else if (counter == 99) {
        visualizedText = getTranslated(context, 'warmup1');
      } else if (counter == 70) {
        visualizedText = getTranslated(context, 'warmup2');
      } else if (counter == 40) {
        visualizedText = getTranslated(context, 'warmup3');
      } else if (counter == 20) {
        visualizedText = getTranslated(context, 'warmup4');
      } else if (counter == 10) {
        visualizedText = getTranslated(context, 'warmup5');
      } else if (counter == 5) {
        visualizedText = getTranslated(context, 'warmup6');
      } else if (counter == 1) {
        visualizedText = getTranslated(context, 'warmup7');
      } else {}
    });
  }

  @override
  Widget build(BuildContext context) {
    TextStyle _textStyleText = TextStyle(
      color: Colors.white,
      fontSize: 40,
    );
    TextStyle _textStyleNumber = TextStyle(
      color: Colors.white,
      fontSize: 70,
    );
    return Scaffold(
      //backgroundColor: Colors.white,
       appBar: ReusableBar(),
      body: SafeArea(
        child: Stack(
          alignment: Alignment.topCenter,
          children: [
            Container(
              width: MediaQuery.of(context).size.width / 1,
              height: MediaQuery.of(context).size.height / 1,
              padding: EdgeInsets.all(100),
              alignment: Alignment.center,
              //color: Colors.grey[850],
              //color: Theme.of(context).colorScheme.background,
              child: Center(
                child: Positioned(
                  width: MediaQuery.of(context).size.width / 1,
                  child: GestureDetector(
                    child: imgButton,
                    onTap:() {
                      _decrementCounter();
                      incrementAppBarCounter();
                  },
                    onTapDown: (tap) {
                      setState(() {
                        imgButton = imgButtonDown;
                      });
                    },
                    onTapUp: (tap) {
                      setState(() {
                        imgButton = imgButtonUp;
                      });
                    },
                  ),
                ),
              ),
            ),
            Positioned(
              top: 0,
              width: MediaQuery.of(context).size.width * 0.7,
              height: MediaQuery.of(context).size.height * 0.28,
              child: Container(
                //width: MediaQuery.of(context).size.width / 1,
                //height: MediaQuery.of(context).size.height * 0.25,
                padding: EdgeInsets.all(8),
                alignment: Alignment.bottomCenter,
                //color:Colors.grey[500],
                child: Text(
                  visualizedText,
                  style: _textStyleText,
                  textAlign: TextAlign.center,
                ),
              ),
            ),
            Positioned(
              width: MediaQuery.of(context).size.width / 1,
              top: MediaQuery.of(context).size.height * 0.58,
              child: Container(
                width: MediaQuery.of(context).size.width / 1,
                //height: MediaQuery.of(context).size.height *0.2,
                padding: EdgeInsets.all(1),
                alignment: Alignment.topCenter,
                //color: Colors.grey[200],
                child: Text('$counter', style: _textStyleNumber),
              ),
            ),
            Positioned(
              bottom: 0,
              width: MediaQuery.of(context).size.width / 1,
              child: Container(
                height: MediaQuery.of(context).size.height / 15,
                padding: EdgeInsets.all(1),
                alignment: Alignment.center,
              ),
            ),
          ],
        ),
      ),
    );
  }
}

Answer 1

对于 [1]，

定位小部件必须是堆栈的后代，并且从定位小部件到其封闭 Stack 的路径必须仅包含 StatelessWidgets 或 StatefulWidgets，显然您正在包装一个Positioned() 带有 Container() 和 Center()

ParentDataWidget 的不正确使用 - 如何修复此错误？

1 个答案: