问题描述

我正在创建一个带有图表的 html 网页，该图表显示电压水平不断变化.我想每秒刷新一次页面，以便条形图中的条形变为新值.我不确定如何像这样更新图表数据.到目前为止，我有以下内容:

I am creating an html web page with a chart on that shows voltage levels continuously changing. I want to refresh the page every second so that the bars in the bar chart go to the new values. I am not sure how to update the chart data like this. I have the following so far:

Chart.plugins.unregister(ChartDataLabels);

function myFunction() {
  var cells = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16];
  var voltages = [];
  for (i = 0; i < 16; i++) {
    voltages[i] = Math.floor(28 + Math.floor(Math.random() * 8)) / 10;
  }

  var colours = [];
  for (i = 0; i < voltages.length; i++) {
    colours[i] = getColour(voltages[i]);
  }

  var ctx = document.getElementById("voltageChart");
  var voltageChart = new Chart(ctx, {
    plugins: [ChartDataLabels],
    type: "bar",
    data: {
      labels: cells,
      datasets: [{
        data: voltages,
        backgroundColor: colours,
      }]
    },
  });

  function updateData(chart) {
    chart.data.datasets[0].data = voltages;
    chart.data.datasets[0].backgroundColor = colours;
    chart.update();
  }

  function refreshData() {
    for (i = 0; i < 16; i++) {
      voltages[i] = Math.floor(28 + Math.floor(Math.random() * 8)) / 10;
    }

    for (i = 0; i < voltages.length; i++) {
      colours[i] = getColour(voltages[i]);
    }

    updateData(voltageChart);
  }

  setInterval(refreshData, 1500);
}

推荐答案

我们可以使用 chart.data.datasets.pop() 推送新数据 chart.data.datasets.push() 然后调用 chart.js 函数 chart.update 重新渲染图形.这是示例:https://codepen.io/bhupendra1011/pen/MWwWogO?editors=1111.

We can use chart.data.datasets.pop() and push new data chart.data.datasets.push() and then invoke chart.js function chart.update to re-render the graph . here is the example : https://codepen.io/bhupendra1011/pen/MWwWogO?editors=1111.

更多关于添加/删除数据这里

More on adding/removing data here

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