javascript - 为 ChartJs 中的图表添加第二个自定义工具提示

Question

我正在尝试为 ChartsJs 中的圆环图添加第二个自定义工具提示。但是，现在我添加了一组新数据(labels2)和一个新函数(labels2)。 donut 出现，但工具提示不出现。有人可以看看下面的代码或我的 JSFiddle 中的代码吗？并看看可能出现什么问题？
这是我第一次使用 Chartsjs 和图表。

以下是该函数的代码:

// HTML
    <canvas id="myChart" height="100"></canvas>

    //JS    
var ctx = document.getElementById("myChart");
var myChart = new Chart(ctx, {
  type: 'doughnut',
  data: {
    labels: ["Red", "Blue", "Yellow"],
     //**LABELS FOR SECOND TOOLTIP**??
    labels2: ["One", "Two", "Three"],
    datasets: [{
      label: '# of Votes',
      data: [12, 19, 3],
      backgroundColor: [
        'rgba(255, 99, 132, 0.2)',
        'rgba(54, 162, 235, 0.2)',
        'rgba(255, 206, 86, 0.2)'
      ],
      borderColor: [
        'rgba(255,99,132,1)',
        'rgba(54, 162, 235, 1)',
        'rgba(255, 206, 86, 1)'
      ],
      borderWidth: 1
    }]
  },
  options: {
    tooltips: {
     // Disable the on-canvas tooltip
        enabled: false,
      custom: function(tooltipModel){
        // Tooltip Element
                var tooltipEl = document.getElementById("myChart");

            // Create element on first render
            if (!tooltipEl){
            tooltipEl = document.getElementById("div");
            tooltipEl.id = 'myChart';
            tooltipEL.innerHTML = '<table></table>';
            document.body.appendChild(tooltipEl);
            }

             // Hide if no tooltip
            if (tooltipModel.opacity === 0){
            tooltipEl.style.opacity = 0;
            return;
            }

             // Set caret Position
            tooltipEl.classList.remove('above', 'below', 'no-transform');
            if (tooltipModel.yAlign) {
            tooltipEl.classList.add(tooltipModel.yAlign);
            } else {
            tooltipEl.classList.add('no-transform');
            }

            function getBody(bodyItem) {
             return bodyItem.lines;
            }
            // Set Text
             if (tooltipModel.body) {
                    var titleLines = tooltipModel.title || [];
                    var bodyLines = tooltipModel.body.map(getBody);

                    var innerHtml = '<thead>';

                    titleLines.forEach(function(title) {
                        innerHtml += '<tr><th>' + title + '</th></tr>';
                    });
                    innerHtml += '</thead><tbody>';

                    bodyLines.forEach(function(body, i) {
                        var colors = tooltipModel.labelColors[i];
                        var style = 'background:' + colors.backgroundColor;
                        style += '; border-color:' + colors.borderColor;
                        style += '; border-width: 2px';
                        var span = '<span style="' + style + '"></span>';
                        innerHtml += '<tr><td>' + span + body + '</td></tr>';
                    });
                    innerHtml += '</tbody>';

                    var tableRoot = tooltipEl.querySelector('table');
                    tableRoot.innerHTML = innerHtml;
                }

                // `this` will be the overall tooltip
               var position = this._chart.canvas.getBoundingClientRect();

                 tooltipEl.style.opacity = 1;
                tooltipEl.style.position = 'absolute';
                tooltipEl.style.left = position.left + window.pageXOffset + tooltipModel.caretX + 'px';
                tooltipEl.style.top = position.top + window.pageYOffset + tooltipModel.caretY + 'px';
                tooltipEl.style.fontFamily = tooltipModel._bodyFontFamily;
                tooltipEl.style.fontSize = tooltipModel.bodyFontSize + 'px';
                tooltipEl.style.fontStyle = tooltipModel._bodyFontStyle;
                tooltipEl.style.padding = tooltipModel.yPadding + 'px ' + tooltipModel.xPadding + 'px'
                tooltipEl.style.pointerEvents = 'none';



      },
      callbacks: {
        title: function(tooltipItem, data) {
          return data['labels'][tooltipItem[0]['index']];
        },
        label: function(tooltipItem, data) {
          return data['datasets'][0]['data'][tooltipItem['index']];
        },
        //**FUNCTION FOR SECOND TOOLTIP
        **label2: function(tooltipItem, data){
            return data['data'][0]['data'][tooltipItem['index']];
        },**
        afterLabel: function(tooltipItem, data) {
          var dataset = data['datasets'][0];
          var percent = Math.round((dataset['data'][tooltipItem['index']] / dataset["_meta"][0]['total']) * 100)
          return '(' + percent + '%)';
        }
      },
      backgroundColor: '#FFF',
      titleFontSize: 16,
      titleFontColor: '#0066ff',
      bodyFontColor: '#000',
      bodyFontSize: 14,
      displayColors: false
    }
  }
})

Answer 1

如果您按如下方式定义 HTML，它应该可以工作。

<div>
  <canvas id="myChart" height="100"></canvas>
    <div id="chartjs-tooltip">
       <table></table>
    </div>
</div>

var ctx = document.getElementById("myChart");
var myChart = new Chart(ctx, {
  type: 'doughnut',
  data: {
labels: ["Red", "Blue", "Yellow"],
labels2: ["One", "Two", "Three"],
datasets: [{
  label: '# of Votes',
  data: [12, 19, 3],
  backgroundColor: [
    'rgba(255, 99, 132, 0.2)',
    'rgba(54, 162, 235, 0.2)',
    'rgba(255, 206, 86, 0.2)'
  ],
  borderColor: [
    'rgba(255,99,132,1)',
    'rgba(54, 162, 235, 1)',
    'rgba(255, 206, 86, 1)'
  ],
  borderWidth: 1
}]
  },
  options: {
tooltips: {
  // Disable the on-canvas tooltip
  enabled: false,
  custom: function(tooltipModel) {
    // Tooltip Element
    var tooltipEl = document.getElementById("chartjs-tooltip");

    // Hide if no tooltip
    if (tooltipModel.opacity === 0) {
      tooltipEl.style.opacity = 0;
      return;
    }

    // Set caret Position
    tooltipEl.classList.remove('above', 'below', 'no-transform');
    if (tooltipModel.yAlign) {
      tooltipEl.classList.add(tooltipModel.yAlign);
    } else {
      tooltipEl.classList.add('no-transform');
    }

    function getBody(bodyItem) {
      return bodyItem.lines;
    }
    // Set Text
    if (tooltipModel.body) {
      var titleLines = tooltipModel.title || [];
      var bodyLines = tooltipModel.body.map(getBody);

      var innerHtml = '<thead>';

      titleLines.forEach(function(title) {
        innerHtml += '<tr><th>' + title + '</th></tr>';
      });
      innerHtml += '</thead><tbody>';

      bodyLines.forEach(function(body, i) {
        var colors = tooltipModel.labelColors[i];
        var style = 'background:' + colors.backgroundColor;
        style += '; border-color:' + colors.borderColor;
        style += '; border-width: 2px';
        var span = '<span style="' + style + '"></span>';
        innerHtml += '<tr><td>' + span + body + '</td></tr>';
      });
      innerHtml += '</tbody>';

      var tableRoot = tooltipEl.querySelector('table');
      tableRoot.innerHTML = innerHtml;
    }

    // `this` will be the overall tooltip
    var position = this._chart.canvas.getBoundingClientRect();

    tooltipEl.style.opacity = 1;
    tooltipEl.style.position = 'absolute';
    tooltipEl.style.left = position.left + window.pageXOffset + tooltipModel.caretX + 'px';
    tooltipEl.style.top = position.top + window.pageYOffset + tooltipModel.caretY + 'px';
    tooltipEl.style.fontFamily = tooltipModel._bodyFontFamily;
    tooltipEl.style.fontSize = tooltipModel.bodyFontSize + 'px';
    tooltipEl.style.fontStyle = tooltipModel._bodyFontStyle;
    tooltipEl.style.padding = tooltipModel.yPadding + 'px ' + tooltipModel.xPadding + 'px'
    tooltipEl.style.pointerEvents = 'none';
  },
  callbacks: {
    title: function(tooltipItem, data) {
      return data['labels'][tooltipItem[0]['index']];
    },
    label: function(tooltipItem, data) {
      return data['datasets'][0]['data'][tooltipItem['index']];
    },
    label2: function(tooltipItem, data) {
      return data['data'][0]['data'][tooltipItem['index']];
    },
    afterLabel: function(tooltipItem, data) {
      var dataset = data['datasets'][0];
      var percent = Math.round((dataset['data'][tooltipItem['index']] / dataset["_meta"][0]['total']) * 100)
      return '(' + percent + '%)';
    }
  },
  backgroundColor: '#FFF',
  titleFontSize: 16,
  titleFontColor: '#0066ff',
  bodyFontColor: '#000',
  bodyFontSize: 14,
  displayColors: false
}
  }
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js"></script>
<div>
    <canvas id="myChart" height="100"></canvas>
    <div id="chartjs-tooltip">
        <table></table>
    </div>
</div>