顫動底部被無窮大像素溢出

Question

我正面臨這個問題，當我將某個小部件添加到列的子項中時，我不斷收到“無限像素溢出的底部”。 現在這是添加名為countdown的新小部件之前的樣子：

以下是我添加countdown后發生的情況：

這是屏幕下半部分的代碼，我在其中添加了countdown ：

    final countdown = Countdown();

    final quizBottomContent = SingleChildScrollView(
      child: Container(
      width: MediaQuery.of(context).size.width,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: <Widget>[quizBottomContentText, quizOptions, countdown],
        ),
      )
    ); 

這是倒計時小部件：

import 'package:flutter/material.dart';
import 'dart:math' as math;

class Countdown extends StatefulWidget {
  @override
  CountdownState createState() => CountdownState();
}

class CountdownState extends State<Countdown> with TickerProviderStateMixin {
  AnimationController controller;

  String get timerString {
    Duration duration = controller.duration * controller.value;
    return '${duration.inMinutes}:${(duration.inSeconds % 60).toString().padLeft(2, '0')}';
  }

  @override
  void initState() {
    super.initState();
    controller = AnimationController(
      vsync: this,
      duration: Duration(seconds: 10),
    );
  }

  @override
  Widget build(BuildContext context) {
    ThemeData themeData = Theme.of(context);
    return Scaffold(
      body: Padding(
        padding: EdgeInsets.all(8.0),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: <Widget>[
            Expanded(
              child: Align(
                alignment: FractionalOffset.center,
                child: AspectRatio(
                  aspectRatio: 1.0,
                  child: Stack(
                    children: <Widget>[
                      Positioned.fill(
                        child: AnimatedBuilder(
                          animation: controller,
                          builder: (BuildContext context, Widget child) {
                            return CustomPaint(
                                painter: TimerPainter(
                              animation: controller,
                              backgroundColor: Colors.white,
                              color: themeData.indicatorColor,
                            ));
                          },
                        ),
                      ),
                      Align(
                        alignment: FractionalOffset.center,
                        child: Column(
                          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                          crossAxisAlignment: CrossAxisAlignment.center,
                          children: <Widget>[
                            Text(
                              "Count Down",
                              style: themeData.textTheme.subhead,
                            ),
                            AnimatedBuilder(
                                animation: controller,
                                builder: (BuildContext context, Widget child) {
                                  return Text(
                                    timerString,
                                    style: themeData.textTheme.display4,
                                  );
                                }),
                          ],
                        ),
                      ),
                    ],
                  ),
                ),
              ),
            ),
            Container(
              margin: EdgeInsets.all(8.0),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                children: <Widget>[
                  FloatingActionButton(
                    child: AnimatedBuilder(
                      animation: controller,
                      builder: (BuildContext context, Widget child) {
                        return Icon(controller.isAnimating
                            ? Icons.pause
                            : Icons.play_arrow);
                      },
                    ),
                    onPressed: () {
                      if (controller.isAnimating)
                        controller.stop();
                      else {
                        controller.reverse(
                            from: controller.value == 0.0
                                ? 1.0
                                : controller.value);
                      }
                    },
                  )
                ],
              ),
            )
          ],
        ),
      ),
    );
  }
}

class TimerPainter extends CustomPainter {
  TimerPainter({
    this.animation,
    this.backgroundColor,
    this.color,
  }) : super(repaint: animation);

  final Animation<double> animation;
  final Color backgroundColor, color;

  @override
  void paint(Canvas canvas, Size size) {
    Paint paint = Paint()
      ..color = backgroundColor
      ..strokeWidth = 5.0
      ..strokeCap = StrokeCap.round
      ..style = PaintingStyle.stroke;

    canvas.drawCircle(size.center(Offset.zero), size.width / 2.0, paint);
    paint.color = color;
    double progress = (1.0 - animation.value) * 2 * math.pi;
    canvas.drawArc(Offset.zero & size, math.pi * 1.5, -progress, false, paint);
  }

  @override
  bool shouldRepaint(TimerPainter old) {
    return animation.value != old.animation.value ||
        color != old.color ||
        backgroundColor != old.backgroundColor;
  }
}

一些上下文：倒計時基本上是一個帶有動畫的計時器，同時倒計時我從這個鏈接中提取。 所以計時器就在按鈕下方。

Answer 1

嘗試設置列mainAxisSize: MainAxisSize.min,

更新

好的，如果您嘗試將倒計時小部件作為列中的小部件，您可以從倒計時小部件的構建方法中移除腳手架並將其包裝在容器中並定義高度

 return Scaffold(
      body: Padding(
        padding: EdgeInsets.all(8.0),
        child: Column(

到

 return Container(
         height: 100,
         child: Padding(
              padding: EdgeInsets.all(8.0),
              child: Column(

Answer 2

我有類似的問題，用Expanded小部件包裝quizBottomContent為我解決了這個問題：

final quizBottomContent = Expanded(
  child: SingleChildScrollView(
    ...
  )
);

Answer 3

只需用容器包裝該小部件並指定高度即可