如何在websocket事件上更新chart.js

当从websocket收到日期时，我正试图使用.update（）方法更新Line chart.js的数据，但这不起作用，我无法解决问题。这是我的代码：

<!doctype html>
<html>
<head>
    <title>Line Chart</title>
    <script src="js/Chart.js"></script>
    <script type="text/javascript">
        if ("WebSocket" in window) {
            var ws = new WebSocket("ws://localhost:8888/ws");
            ws.onopen = function() {
                ws.send("data");
            };
            ws.onmessage = function(evt) {
                var received_msg = JSON.parse(evt.data)
                alert(received_msg[0]);
                alert(received_msg[1]);
                lineChartData.labels = received_msg[0];
                lineChartData.datasets[0].data = received_msg[1];
                lineChartData.update();
            };

            ws.onclose = function() {
                // websocket is closed.
                console.log("Connection is closed...");
            };
        } else {
            // The browser doesn't support WebSocket
            console.log("WebSocket NOT supported by your Browser!");
        }
    </script>
</head>
<body>
    <div style="width:70%">
        <div>
            <canvas id="canvas" height="450" width="800"></canvas>
        </div>
    </div>

    <script>
        var lineChartData = {
            labels: [],
            datasets: [{
                label: "My Second dataset",
                fillColor: "rgba(151,187,205,0.2)",
                strokeColor: "rgba(151,187,205,1)",
                pointColor: "rgba(151,187,205,1)",
                pointStrokeColor: "#fff",
                pointHighlightFill: "#fff",
                pointHighlightStroke: "rgba(151,187,205,1)",
                data: []
            }]
        }
        var options = {
            responsive: true,
            scaleShowGridLines: false,
            scaleLineColor: "rgba(0,0,0,.1)",
        }

        var ctx = document.getElementById("canvas").getContext("2d");
        window.myLine = new Chart(ctx).Line(lineChartData, options);
    </script>
</body>
</html>

这是我想更新图表的部分：

ws.onmessage = function(evt) {
                    var received_msg = JSON.parse(evt.data)
                    alert(received_msg[0]);
                    alert(received_msg[1]);
                    lineChartData.labels = received_msg[0];
                    lineChartData.datasets[0].data = received_msg[1];
                    lineChartData.update();
                };

从警报输出中，我收到了格式良好的良好数据，但更新不起作用。

你能帮我吗？

问题是您正在更新数据"lineChartData"，但您想在图表上调用update（）

所以

ws.onmessage = function(evt) {
                var received_msg = JSON.parse(evt.data)
                alert(received_msg[0]);
                alert(received_msg[1]);
                lineChartData.labels = received_msg[0];
                lineChartData.datasets[0].data = received_msg[1];
                window.myLine.update(); //<-- magic
            };

如果您绘制的图表不是chart.js例如，ccchart

http://jsfiddle.net/UkdvS/602/
https://github.com/toshirot/ccchart

    var chartdata81 = {
      "config": {
        "title": "WebSocket Line Chart",
        "subTitle": "realtime",
        "bg": "#666",
        "type": "line",
        "xLines": [{
                    "useRow":1,
                    "color":"rgba(250,250,250,0.7)"
        }]
      },
      "data": [
        ["year"],
        ["data1"],
        ["data2"]
      ]
    };
    ccchart
    .init('hoge', chartdata81)
    .ws('ws://ccchart.com:8016')
    .on('message', ccchart.wscase.oneColAtATime);

此时WebSocket数据格式如下：

["23:41:47",58,41]
["23:41:47",30,46]
["23:41:47",7,35]
["23:41:47",46,34]
["23:41:47",59,41]
["23:41:47",95,47]
["23:41:47",22,40]
["23:41:47",73,35]
・・・・
・・・・
・・・・

@请参阅qiita.com/toshirot/items/a461cdc8c2079d9b8530（日语）

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