使用 syncfusion 图表，图表未显示在屏幕上

Question

创建了一个简单的条形图，但它不会显示在页面上。

这是我的代码

import 'package:flutter/material.dart';
import 'bar_chart_sample1.dart';

class BarChartPage extends StatelessWidget {
  const BarChartPage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      color: Color.fromARGB(255, 166, 166, 166),
      child: ListView(
        children: <Widget>[
          Padding(
            padding: EdgeInsets.only(
              left: 28,
              right: 28,
            ),
            child: BarChartWidget(),
          ),
          SizedBox(height: 22),
        ],
      ),
    );
  }
}

import 'package:flutter/material.dart';
import 'package:syncfusion_flutter_charts/charts.dart';

class BarChartWidget extends StatefulWidget {
  const BarChartWidget({Key? key}) : super(key: key);

  @override
  State<BarChartWidget> createState() => _BarChartWidgetState();
}

class _BarChartWidgetState extends State<BarChartWidget> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: Center(
            child: Container(
      child:
          SfCartesianChart(primaryXAxis: CategoryAxis(), series: <ChartSeries>[
        // Initialize line series
        LineSeries<ChartData, String>(
            dataSource: [
              // Bind data source
              ChartData('Jan', 35),
              ChartData('Feb', 28),
              ChartData('Mar', 34),
              ChartData('Apr', 32),
              ChartData('May', 40)
            ],
            xValueMapper: (ChartData data, _) => data.x,
            yValueMapper: (ChartData data, _) => data.y)
      ]),
    )));
  }
}

class ChartData {
  ChartData(this.x, this.y);
  final String x;
  final double? y;
}

它应该看起来像这样

我做错什么了？

我做错什么了？ 我做错什么了？ 我做错什么了？ 我做错什么了？ 我做错什么了？ 我做错什么了？ 我做错什么了？ 我做错什么了？ 我做错什么了？ 我做错什么了？ 我做错什么了？

Answer 1

您已将脚手架小部件包装在 ListView 中，这就是您遇到此异常的原因。 Scaffold 小部件始终必须是父小部件，或者如果它与任何其他小部件一起包装，我们必须需要指定父小部件的大小。因此，我们建议您避免将 Scaffold 小部件包装在 ListView 中。

Answer 2

即使我也面临着同样的问题..但我在 Scafold 上没有任何父母.. 该图在 Emulator 中看起来不错，但在 Emulator 中根本没有显示

@override
  Widget build(BuildContext context) {
    TextTheme _textTheme = Theme.of(context).textTheme;
    // TODO: implement build
    return Scaffold(
      backgroundColor: Colors.white,
      body: Column(
        children: [
          SizedBox(
            height: 20,
          ),
          Padding(
            padding: const EdgeInsets.fromLTRB(20, 10, 20, 10),
            child: Row(
              children: [
                GestureDetector(
                  onTap: () {
                    Navigator.pop(context);
                  },
                  child: Icon(
                    Icons.arrow_back_ios,
                    color: Colors.blueAccent,
                    size: 20,
                  ),
                ),
                SizedBox(
                  width: 10,
                ),
                Image.network(
                  widget.cryptoData.cryptoImage!,
                  height: 20,
                  width: 20,
                  // fit: BoxFit.fill,
                ),
                SizedBox(
                  width: 6,
                ),
                Text(widget.cryptoData.cryptoName!,
                    style: _textTheme.labelSmall),
                SizedBox(
                  width: 2,
                ),
                Text('(' + widget.cryptoData.cryptoSymbol! + ')',
                    style: _textTheme.titleMedium)
              ],
            ),
          ),
          SizedBox(
            height: 10,
          ),
          Padding(
            padding: const EdgeInsets.fromLTRB(20, 0, 20, 10),
            child: Row(
              children: [
                Text(
                    "$" +
                        limitDecimalToTwo(
                            widget.cryptoData.cryptoValue.toString()),
                    style: _textTheme.labelLarge),
                SizedBox(
                  width: 20,
                ),
                Text(
                    limitDecimalToTwo(
                        widget.cryptoData.cryptoValueChange.toString()),
                    style: TextStyle(
                        color:
                            widget.cryptoData.cryptoValueChange.toString()[0] ==
                                    '-'
                                ? Colors.red
                                : Colors.green,
                        fontSize: 14)),
              ],
            ),
          ),
          Expanded(
              flex: 4,
              child: Container(
                child: SfCartesianChart(
                  primaryXAxis: CategoryAxis(),
                  primaryYAxis: CategoryAxis(
                      isVisible: false,
                      majorGridLines: const MajorGridLines(width: 0)),
                  series: <ChartSeries<CryptoData, String>>[
                    LineSeries<CryptoData, String>(
                        dataSource: cryptoDataList,
                        xValueMapper: (CryptoData crypto, _) =>
                            getDateInProperFormat(crypto.date),
                        yValueMapper: (CryptoData crypto, _) => crypto.value),
                  ],
                ),
              )),
          SizedBox(
            height: 20,
          ),
          Padding(
            padding: const EdgeInsets.all(15),
            child: Expanded(
                flex: 2,
                child: CryptoRowWidget(
                    cryptoName: widget.cryptoData.cryptoName,
                    cryptoCode: widget.cryptoData.cryptoSymbol,
                    cryptoImage: widget.cryptoData.cryptoImage,
                    cryptoValue: widget.cryptoData.cryptoValue.toString(),
                    cryptoValueChange:
                        widget.cryptoData.cryptoValueChange.toString(),
                    cryptoQunatityAvailable: '')),
          ),
          Padding(
            padding: const EdgeInsets.all(15),
            child: Expanded(
              flex: 1,
              child: Row(
                crossAxisAlignment: CrossAxisAlignment.center,
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  ElevatedButton(
                      style: ElevatedButton.styleFrom(shape: StadiumBorder()),
                      onPressed: () {
                        showAlertDialog(context, _textTheme, 'Buy');
                      },
                      child: Padding(
                          padding: const EdgeInsets.fromLTRB(30, 10, 30, 10),
                          child: Text(
                            'Buy',
                            style: _textTheme.bodySmall,
                          ))),
                  SizedBox(
                    width: 40,
                  ),
                  ElevatedButton(
                      style: ElevatedButton.styleFrom(shape: StadiumBorder()),
                      onPressed: () {
                        showAlertDialog(context, _textTheme, 'Sell');
                      },
                      child: Padding(
                          padding: const EdgeInsets.fromLTRB(30, 10, 30, 10),
                          child: Text(
                            'Sell',
                            style: _textTheme.bodySmall,
                          ))),
                ],
              ),
            ),
          )
        ],
      ),
    );
  }