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具有相同配置但不同数据的多个 Chartjs 图表

在我的脚本中，我使用一个函数来创建图表的配置。当我使用该函数创建第一个图表时，一切正常。但是当我第二次使用不同的数据时，图表没有出现。谁能解释为什么它不起作用并且可能更新我的代码使其起作用？希望你理解我的问题


编码如下：


<!DOCTYPE html>

<html>


<head>

    <meta charset="UTF-8">

    <meta name="viewport" content="width=device-width, initial-scale=1.0">

    <meta http-equiv="X-UA-Compatible" content="ie=edge">

    <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.3/Chart.min.js"></script>

    <script src="https://code.jquery.com/jquery-3.3.1.js"></script>

    <script src="https://cdn.jsdelivr.net/npm/chartjs-plugin-datalabels"></script>

    <script src="./js/script.js"></script>

</head>


<body>

    <div style="width: 100%; display: table;">

        <div style="display: table-row; height: 300px;">

            <div style="width:25%; display: table-cell;">

                <canvas id="canvas"></canvas>

            </div>

            <div style="width:25%; display: table-cell;">

                <canvas id="canvas1"></canvas>

            </div>

            <div style="width:25%; display: table-cell;">

                <canvas id="canvas2"></canvas>

            </div>

            <div style="width:25%; display: table-cell;">

                <canvas id="canvas3"></canvas>

            </div>

        </div>

    </div>


繁星淼淼
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1回答

一只萌萌小番薯

问题出在数据标签格式化程序中，其中 _meta 索引并不总是 0。如果您使用多个图表，第二个图表索引为 1，第三个图表索引为 2 等。我添加了这行代码以使用 Object.keys() 获取当前的 metaIndexlet metaIndex = Object.keys(ctx.dataset._meta)[0]let sum = ctx.dataset._meta[metaIndex].total;这是工作代码：<!DOCTYPE html><html><head>&nbsp; &nbsp; <meta charset="UTF-8">&nbsp; &nbsp; <meta name="viewport" content="width=device-width, initial-scale=1.0">&nbsp; &nbsp; <meta http-equiv="X-UA-Compatible" content="ie=edge">&nbsp; &nbsp; <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.3/Chart.min.js"></script>&nbsp; &nbsp; <script src="https://code.jquery.com/jquery-3.3.1.js"></script>&nbsp; &nbsp; <script src="https://cdn.jsdelivr.net/npm/chartjs-plugin-datalabels"></script>&nbsp; &nbsp; <script src="./js/script.js"></script></head><body>&nbsp; &nbsp; <div style="width: 100%; display: table;">&nbsp; &nbsp; &nbsp; &nbsp; <div style="display: table-row; height: 300px;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <div style="width:25%; display: table-cell;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <canvas id="canvas"></canvas>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </div>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <div style="width:25%; display: table-cell;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <canvas id="canvas1"></canvas>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </div>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <div style="width:25%; display: table-cell;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <canvas id="canvas2"></canvas>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </div>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <div style="width:25%; display: table-cell;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <canvas id="canvas3"></canvas>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </div>&nbsp; &nbsp; &nbsp; &nbsp; </div>&nbsp; &nbsp; </div>&nbsp; &nbsp; <script>&nbsp; &nbsp; &nbsp; function chartconfig(data, label, labels) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Chart.defaults.global.defaultFontFamily = 'Lato';&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Chart.defaults.global.defaultFontSize = 12;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; config = {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; type: 'doughnut',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; data: {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; datasets: [{&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; data,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; backgroundColor: ['rgb(0, 140, 75)', 'rgb(94, 140, 0)'],&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; label,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; labels,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; hoverBorderWidth: 3,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; fill: false,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; },],&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; },&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; options: {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; plugins: {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; datalabels: {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; color: '#000',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; align: 'start',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; anchor: 'end',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; display: 'auto',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; formatter: (value, ctx) => {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; let chartIndex = Object.keys(ctx.dataset._meta)[0]&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; let sum = ctx.dataset._meta[chartIndex].total;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; let percentage = (value * 100 / sum).toFixed(2) + "%";&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; let text = value + '\n' + percentage;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return text;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; },&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; },&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; rotation: -0.8 * Math.PI,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; legend: {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; position: 'bottom',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; labels: {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; fontColor: '#000',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; generateLabels: () => {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; let labels = [];&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; config.data.datasets.forEach((ds, iDs) => labels = labels.concat(ds.labels.map((l, iLabel) => ({&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; datasetIndex: iDs,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; labelIndex: iLabel,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; text: l,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; fillStyle: ds.backgroundColor[iLabel],&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; hidden: chart ? chart.getDatasetMeta(iDs).data[iLabel].hidden : false,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; strokeStyle: '#fff'&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }))));&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return labels;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; },&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onClick: (event, legendItem) => {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; let metaData = chart.getDatasetMeta(legendItem.datasetIndex).data;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; metaData[legendItem.labelIndex].hidden = !metaData[legendItem.labelIndex].hidden;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; chart.update();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; },&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; tooltips: {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; callbacks: {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; label: (tooltipItem, data) => {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; let dataset = data.datasets[tooltipItem.datasetIndex];&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; let index = tooltipItem.index;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return dataset.labels[index] + ": " + dataset.data[index];&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; };&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return config;&nbsp; &nbsp; &nbsp; }&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; function addData(data, backgroundColor, labels) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; chart.data.datasets.push({&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; data,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; backgroundColor,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; labels,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; fill: false,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; });&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; chart.update();&nbsp; &nbsp; &nbsp; }&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; var data = [160, 150,];&nbsp; &nbsp; &nbsp; var label = ['Februar'];&nbsp; &nbsp; &nbsp; var labels = ['21.02.2020', '22.02.2020'];&nbsp; &nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; var config = chartconfig(data, label, labels);&nbsp; &nbsp; &nbsp; var ctx1 = document.getElementById("canvas").getContext("2d");&nbsp; &nbsp; &nbsp; var chart = new Chart(ctx1, config); // worked fine and appears&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; var data = [120, 230,];&nbsp; &nbsp; &nbsp; var label = ['März'];&nbsp; &nbsp; &nbsp; var labels = ['21.03.2020', '22.03.2020'];&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; var config = chartconfig(data, label, labels);&nbsp; &nbsp; &nbsp; var ctx2 = document.getElementById("canvas1").getContext("2d");&nbsp; &nbsp; &nbsp; var chart = new Chart(ctx2, config); //didnt appear&nbsp;&nbsp;&nbsp; </script>&nbsp; </body>&nbsp; </html>
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