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动态更新chartjs图表的值

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我使用chartjs创建了一个基本条形图,它工作正常 . 现在我想基于时间间隔更新值 . 我的问题是,在创建图表后,我不知道如何正确更新其值...

我的代码:

var ctx = $("#myChart").get(0).getContext("2d");

var dts = [
    {
        fillColor: "rgba(220,220,220,0.5)",
        strokeColor: "rgba(220,220,220,1)",
        data: [0, 0, 0, 0, 0]
    }
];

var data = {
    labels: ["Core#1", "Core#2", "Core#3", "Core#4", "Total"],
    datasets: dts
};

var chart = new Chart(ctx);
chart.Bar(data);

//test code
setInterval( function () {                        
    data.datasets[0].data = [random(), random(), random(), random(), random()];
    chart.Bar(data);

},2000);

在测试代码中,我用 datasets[0].data 更新值 - 这是正确的方法吗?这个问题是,每当我调用 chart.Bar() 时,值都会重置为0然后设置为随机值(就像我正在重新创建图表一样) . 这样,所有动画总是从0到值,看起来很奇怪 . 我希望如果我将值从50更新为10,则条形图将从50下降到10并且不会设置为0然后动画为10 .

我没有在文档中找到任何关于此的内容......我做错了什么或者这个库是不可能的?

10 回答

  • 30

    如果destroy()和clear()不起作用(就像我的经验)你可以使用jquery删除画布并再次追加它 .

    $('#chartAmazon').remove();
        $('#chartBar').append('<canvas id="chartAmazon"></canvas>');
    
        var ctxAmazon = $("#chartAmazon").get(0).getContext("2d");
          var AmazonChart = new Chart(ctxAmazon, {
            type: 'doughnut',
            data: dataAmazon,
            options: optionsA
        });
    
  • -8

    Update: 看起来charjs已经更新(见下面的评论) . 有一些例子看起来非常好:

    Original Post

    截至2013年11月,似乎很少有更新图表的选项 .

    有一个good example here(下面重复)向折线图添加新点 . 仍然有点跳跃但不是太糟糕 . 但是,我认为效果可能取决于您使用的图表 .

    它确实看起来像是在开发流程中的某个地方 . 我没有看到任何发布日期的迹象:https://github.com/nnnick/Chart.js/issues/13

    JS

    $(document).ready(function(){
      var count = 10;
      var data = {
          labels : ["1","2","3","4","5", "6", "7", "8", "9", "10"],
            datasets : [
              {
                    fillColor : "rgba(220,220,220,0.5)",
                    strokeColor : "rgba(220,220,220,1)",
                    pointColor : "rgba(220,220,220,1)",
                    pointStrokeColor : "#fff",
                    data : [65,59,90,81,56,45,30,20,3,37]
                },
                {
                    fillColor : "rgba(151,187,205,0.5)",
                    strokeColor : "rgba(151,187,205,1)",
                    pointColor : "rgba(151,187,205,1)",
                    pointStrokeColor : "#fff",
                    data : [28,48,40,19,96,87,66,97,92,85]
                }
            ]
      }
      // this is ugly, don't judge me
      var updateData = function(oldData){
        var labels = oldData["labels"];
        var dataSetA = oldData["datasets"][0]["data"];
        var dataSetB = oldData["datasets"][1]["data"];
    
        labels.shift();
        count++;
        labels.push(count.toString());
        var newDataA = dataSetA[9] + (20 - Math.floor(Math.random() * (41)));
        var newDataB = dataSetB[9] + (20 - Math.floor(Math.random() * (41)));
        dataSetA.push(newDataA);
        dataSetB.push(newDataB);
        dataSetA.shift();
        dataSetB.shift();    };
    
      var optionsAnimation = {
        //Boolean - If we want to override with a hard coded scale
        scaleOverride : true,
        //** Required if scaleOverride is true **
        //Number - The number of steps in a hard coded scale
        scaleSteps : 10,
        //Number - The value jump in the hard coded scale
        scaleStepWidth : 10,
        //Number - The scale starting value
        scaleStartValue : 0
      }
    
      // Not sure why the scaleOverride isn't working...
      var optionsNoAnimation = {
        animation : false,
        //Boolean - If we want to override with a hard coded scale
        scaleOverride : true,
        //** Required if scaleOverride is true **
        //Number - The number of steps in a hard coded scale
        scaleSteps : 20,
        //Number - The value jump in the hard coded scale
        scaleStepWidth : 10,
        //Number - The scale starting value
        scaleStartValue : 0
      }
    
      //Get the context of the canvas element we want to select
      var ctx = document.getElementById("myChart").getContext("2d");
      var optionsNoAnimation = {animation : false}
      var myNewChart = new Chart(ctx);
      myNewChart.Line(data, optionsAnimation);  
    
      setInterval(function(){
        updateData(data);
        myNewChart.Line(data, optionsNoAnimation)
        ;}, 2000
      );
    });
    
    
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    e(f,g),n+m*g,e(f,g)):b.lineTo(n+m*g,e(f,g));b.stroke();c.datasetFill?(b.lineTo(n+m*(a.datasets[f].data.length-1),p),b.lineTo(n,p),b.closePath(),b.fillStyle=a.datasets[f].fillColor,b.fill()):b.closePath();if(c.pointDot){b.fillStyle=a.datasets[f].pointColor;b.strokeStyle=a.datasets[f].pointStrokeColor;b.lineWidth=c.pointDotStrokeWidth;for(g=0;g<a.datasets[f].data.length;g++)b.beginPath(),b.arc(n+m*g,p-d*v(a.datasets[f].data[g],j,k),c.pointDotRadius,0,2*Math.PI,!0),b.fill(),b.stroke()}}},b)},L=function(a,
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    b.moveTo(g,p);b.lineTo(g,p-d*v(a.datasets[e].data[f],j,k)+c.barStrokeWidth/2);b.lineTo(g+s,p-d*v(a.datasets[e].data[f],j,k)+c.barStrokeWidth/2);b.lineTo(g+s,p);c.barShowStroke&&b.stroke();b.closePath();b.fill()}}},b)},D=window.requestAnimationFrame||window.webkitRequestAnimationFrame||window.mozRequestAnimationFrame||window.oRequestAnimationFrame||window.msRequestAnimationFrame||function(a){window.setTimeout(a,1E3/60)},F={}};
    

    HTML

    <html>
        <head>
            <script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
        </head>
        <body>
            <h1>Live Updating Chart.js</h1>
    
            <canvas id="myChart" width="400" height="150"></canvas>
    
    
        </body>
    </html>
    
  • 54

    根据文档,现在有一个 update() 方法将重新绘制图表 .

    .update( )
    

    在Chart实例上调用update()将使用任何更新的值重新渲染图表,允许您编辑多个现有点的值,然后在一个动画渲染循环中渲染它们 .

    myBarChart.datasets[0].bars[2].value = 50;
    // Would update the first dataset's value of 'March' to be 50
    myBarChart.update();
    // Calling update now animates the position of March from 90 to 50.
    
  • 90

    以下是如何在ChartJs的最后一个版本中执行此操作:

    setInterval(function(){
        chart.data.datasets[0].data[5] = 80;
        chart.data.labels[5] = "Newly Added";
        chart.update();
    }
    

    看看这个clear video

    或在jsfiddle测试

  • 24

    你也可以使用destroy()函数 . 像这样

    if( window.myBar!==undefined)
         window.myBar.destroy();
     var ctx = document.getElementById("canvas").getContext("2d");
     window.myBar = new Chart(ctx).Bar(barChartData, {
         responsive : true,
     });
    
  • 6

    删除画布dom并再次添加 .

    function renderChart(label,data){
    
        $("#canvas-wrapper").html("").html('<canvas id="storeSends"></canvas>');
        var lineChartData = {
            labels : label,
            datasets : [
                {
                    fillColor : "rgba(49, 195, 166, 0.2)",
                    strokeColor : "rgba(49, 195, 166, 1)",
                    pointColor : "rgba(49, 195, 166, 1)",
                    pointStrokeColor : "#fff",
                    data : data
                }
            ]
    
        }
        var canvas = document.getElementById("storeSends");
        var ctx = canvas.getContext("2d");
    
        myLine = new Chart(ctx).Line(lineChartData, {
            responsive: true,
            maintainAspectRatio: false
        });
    }
    
  • 4

    您只需要更改 chartObject.data.datasets 值并像这样调用 update()

    chartObject.data.datasets = newData.datasets;
    chartObject.data.labels = newData.labels;
    chartObject.update();
    
  • 0

    我认为现在不可能 .

    然而,正如作者在此暗示的那样,这应该很快就会出现:https://github.com/nnnick/Chart.js/issues/161#issuecomment-20487775

  • 3

    最简单的方法是替换canvas元素,然后再次调用new Chart():

    function reloadMyChart() {
        $('myChart').replaceWith('<canvas id="myChart"></canvas>');
        new Chart(document.getElementById("myChart"), {
            data: yourChartData,
            type: yourChartType,
            options: yourChartOptions
        });
    }
    

    当然,您必须使用初始化Chart.js所需的正确值替换yourChartData,yourChartType和yourChartOptions . 见Chart.js Docs .

    您可以通过单击按钮或任何其他需要的事件来调用reloadMyChart函数 . 您可能会向此函数添加参数并使用这些参数进行REST调用以动态更新图表,如下所示:

    function reloadMyChart(param1, param2) {
        $('myChart').replaceWith('<canvas id="myChart"></canvas>');
        $.get("restUrl?param1=" + param1 + "&param2=" + param2 + ",
            function(data) {
                // call new Chart() here and use returned data
            }
        );
    

    希望能帮助到你! =)

  • 2

    这么简单,只需替换图表canvas元素即可 .

    $('#canvas') . replaceWith('id =“canvas”height =“200px”width =“368px”>');

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