flutter - flutter 中的计时器控制

我试图在2秒后将一个 bool(boolean) 值设置为false(showSpinner)，但无法处理，主要思想是比显示解决方案显示加载微调器2秒钟，但旋转器永不停止且解决方案从不显示(旋转器正在加载微调器，文字=解决方案)

@override
  void initState(){
    super.initState();
    showSpinner=true;

      Timer(Duration(seconds: 2),(){
        setState(() {
          showSpinner=false;
        });
      });

  }

Widget build(BuildContext context) {


     Widget child;
      if (showSpinner == true && isPressed4 == true) {
        setState(() {
          Timer(Duration(seconds: 2), () {
            showSpinner == false;
          });
        });

        child = spinkit;
      }

      if (showSpinner == false && isPressed4 == true) {
        text = simpleInterest.accumulationFunction(
            time, yearlySimpleInterestRate, principal);
        child = Text(
          text,
          style: TextStyle(fontSize: 18),
          textAlign: TextAlign.center,
        );
      }

有3个按钮(如果按钮true为true，则按钮1为isPressed1，按钮2为isPressed2，按钮3为isPressd3)

 var floatingActionButton1 = FloatingActionButton(
          onPressed: () {
            setState(() {
              isPressed1 = !isPressed1;
            });
            setState(() {
              principal = double.parse(_principalController.text);
            });
            setState(() {
              if (isPressed3 == true && isPressed2 == true && isPressed1 == true) {
                isPressed4 = true;
              }
            });
          },
          elevation: 40,
          backgroundColor: isPressed1 ? Colors.lightGreenAccent : null,
          heroTag: "btn1",
          child: Icon(Icons.check),
        );

最佳答案

我不知道spinkit和isPressed4是什么，但是我会这样做:

  bool showSpinner;

  @override
  void initState() {
    super.initState();
    showSpinner = true;

    Timer(Duration(seconds: 2), () {
      setState(() {
        showSpinner = false;
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text('Title'),
        ),
        body: buildBody()
    );
  }

  Widget buildBody(){
    return showSpinner ?
    CircularProgressIndicator() :
    Text(
      'The answer',
    );
  }

UPD:

最初我有2秒。然后:

如果尚未按下showSpinner == false和floatingActionButton1，那么我会收到文本The time is up!。

如果尚未按下showSpinner == true和floatingActionButton1，那么我会收到文本Button 4 is not pressed yet。

如果已按下showSpinner == true和floatingActionButton1，那么我会得到CircularProgressIndicator()(如问题中所述)。

如果按下了showSpinner == false和floatingActionButton1，那么我得到带有Text的The answer(如问题中所示):

  bool showSpinner;

  var floatingActionButton1;

  bool isPressed1;
  bool isPressed2;
  bool isPressed3;
  bool isPressed4;

  @override
  void initState() {
    super.initState();
    showSpinner = true;

    isPressed1 = false;
    isPressed2 = true;
    isPressed3 = true;
    isPressed4 = false;

    floatingActionButton1 = FloatingActionButton(
      onPressed: () {
        setState(() {
          isPressed1 = !isPressed1;

          if (isPressed3 == true && isPressed2 == true && isPressed1 == true) {
            isPressed4 = true;
          }
        });
      },
      backgroundColor: isPressed1 ? Colors.lightGreenAccent : null,
      child: Icon(Icons.check),
    );

    Timer(Duration(seconds: 2), () {
      setState(() {
        showSpinner = false;
      });
    });
  }


  Widget build(BuildContext context) {
    Widget child;

    if(showSpinner == false && isPressed4 == false)
      child = Text('The time is up!');

    else if(showSpinner == true && isPressed4 == false)
      child = Text('Button 4 is not pressed yet');

    else if (showSpinner == true && isPressed4 == true) {
      child = CircularProgressIndicator();
    }

    else if (showSpinner == false && isPressed4 == true) {
      child = Text(
        'The answer',
        style: TextStyle(fontSize: 18),
        textAlign: TextAlign.center,
      );
    }

    return Scaffold(
        appBar: AppBar(
          title: Text('Title'),
        ),
        body: child,
      floatingActionButton: floatingActionButton1,
    );
  }