个人中心
gpt4 book ai didi

javascript - CanvasJS 折线图生成？

转载 作者：行者123 更新时间：2023-12-03 10:05:25 24 4
gpt4 key购买 nike

我正忙着尝试制作一个用于实时数据显示的 javascript 图表。我找到了这个 CanvasJS API。默认代码 specific chart他们的网页上的内容很好，但是当然，他们获取数据的部分，他们将变量数组留空并使用数学随机化数据函数，以便随机生成特定数据并在图表中使用。

但是，我想用来 self 想使用的特定表的数据库数据来填充该数组!

我已经尝试了很多方法，但如果我实现了我的部分，图表将不再显示。我做错了什么？

这是我使用的 3 个代码:

默认代码(仅供比较):

<!DOCTYPE HTML>
<html>

<head>
    <script type="text/javascript">
    window.onload = function () {

        var dps = []; // dataPoints

        var chart = new CanvasJS.Chart("chartContainer",{
            title :{
                text: "Live Random Data"
            },          
            data: [{
                type: "line",
                dataPoints: dps 
            }]
        });

        var xVal = 0;
        var yVal = 100; 
        var updateInterval = 20;
        var dataLength = 500; // number of dataPoints visible at any point

        var updateChart = function (count) {
            count = count || 1;
            // count is number of times loop runs to generate random dataPoints.

            for (var j = 0; j < count; j++) {   
                yVal = yVal +  Math.round(5 + Math.random() *(-5-5));
                dps.push({
                    x: xVal,
                    y: yVal
                });
                xVal++;
            };
            if (dps.length > dataLength)
            {
                dps.shift();                
            }

            chart.render();     

        };

        // generates first set of dataPoints
        updateChart(dataLength); 

        // update chart after specified time. 
        setInterval(function(){updateChart()}, updateInterval); 

    }
    </script>
    <script type="text/javascript" src="/assets/script/canvasjs.min.js"></script>
</head>
<body>
    <div id="chartContainer" style="height: 300px; width:100%;">
    </div>
</body>
</html>

我自己的图表代码，基于上述代码:

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title></title>
    <script src="jquery.js"></script>
    <script src="jquery.canvasjs.js" ></script>
    <script src="canvasjs.js"></script>

    <script type="text/javascript">
        $(document).ready(function () {

            $.getJSON("data.php", function (result) {

                var chart = new CanvasJS.Chart("chartContainer", {
                    data: [
                        {
                            dataPoints: result
                        }
                    ]
                });

                chart.render();
            });
        });
    </script>
</head>
<body>

    <div id="chartContainer" style="width: 800px; height: 380px;"></div>

</body>
</html>

和我的 data.php 显示以下输出:

[{"x":"1","y":"5"},{"x":"2","y":"5"},{"x":"3","y":"4"},{"x":"4","y":"1"},{"x":"5","y":"8"},{"x":"6","y":"9"},{"x":"7","y":"5"},{"x":"8","y":"6"},{"x":"9","y":"4"},{"x":"10","y":"7"}]

 <?php
    //header('Content-Type: application/json');
    $con = mysqli_connect("localhost","root","","WebApplication");

    // Check connection
    if (mysqli_connect_errno($con))
    {
        echo "Failed to connect to DataBase: " . mysqli_connect_error();
    } 
    else
    {
    $data_points = array();

    $result = mysqli_query($con, "SELECT * FROM info");

    while($row = mysqli_fetch_array($result))
    {        
        $point = array("x" => $row['id'] , "y" => $row['acceleration']);

        array_push($data_points, $point);        
    }

        echo json_encode($data_points, 32); //define('JSON_NUMERIC_CHECK',32);   // Since PHP 5.3.3

    }
    mysqli_close($con);



    ?>

希望您有足够的信息!

谢谢

米尔

编辑

我将“我自己的图表”中的代码交换为以下代码，基于以下@feedback-comment:Anjali Jain

-->

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title></title>
    <script src="jquery.js"></script>
    <script src="jquery.canvasjs.js" ></script>
    <script src="canvasjs.js"></script>
    <script type="text/javascript" src="canvasjs.min.js"></script>


    <script type="text/javascript">
        $(document).ready(function () {

                $.getJSON("data.php", function (result) {

                var dataPoints = [];

                for (var i = 0; i <= result.length - 1; i++) {
                dataPoints.push({ x: Number(result[i].x), y: Number(result[i].y) });
                }

                var chart = new CanvasJS.Chart("chartContainer", {
                data: [
                {
                dataPoints: dataPoints
                }
                ]
                });

                chart.render();
                });
        });
    </script>
</head>
<body>

    <div id="chartContainer" style="width: 800px; height: 380px;"></div>

</body>
</html>

然而，我还是一无所获。

最佳答案

当您直接传递字符串时，CanvasJS 要求 x 和 y 值为数字。您可以将它们转换为数字，如下所示

$.getJSON("data.php", function (result) {

    var dataPoints = [];

    for (var i = 0; i <= result.length - 1; i++) {
        dataPoints.push({ x: Number(result[i].x), y: Number(result[i].y) });
    }

    var chart = new CanvasJS.Chart("chartContainer", {
        data: [
        {
            dataPoints: dataPoints
        }
        ]
    });

    chart.render();
});

关于javascript - CanvasJS 折线图生成？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/30383125/

24 4 0
文章推荐： javascript - JQuery 仅选择所选元素内的元素
文章推荐： ruby-on-rails - 使用 Chronic 会损害您的时间感吗？
文章推荐： batch-file - 从批处理文件中一一启动宏
文章推荐： javascript - ‘node.js’: Does it need to be run a server?
行者123
个人简介

我是一名优秀的程序员,十分优秀！

滴滴打车优惠券免费领取
滴滴打车优惠券
全站热门文章
Copyright 2021 - 2024 cfsdn All Rights Reserved 蜀ICP备2022000587号
广告合作:1813099741@qq.com 6ren.com