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我正忙着制作一个用于实时数据显示的 javascript 图表。我找到了这个 CanvasJS API。他们网页上该特定图表的默认代码很好，但是他们获取数据的部分当然是他们将变量数组留空并改用数学随机化数据函数，以便随机生成特定数据和图中使用。

但是，我想用来自我想使用的特定表的数据库数据来填充该数组！

我已经尝试了很多事情，但如果我实施我的部分，图表将不再显示。我究竟做错了什么？

以下是我使用的 3 个代码：

默认代码（仅用于比较目的）：

<!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，基于上面的代码：

<!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);



    ?>

希望你有足够的信息！

谢谢

米尔

编辑

我根据来自Anjali Jain的@feedback-comment 将“我自己的图表”中的代码替换为以下代码

-->

<!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" 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，我仍然一无所获。

4

1 回答 1

1

当您直接传递字符串时，CanvasJS 要求 x 和 y 值是数字。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();
});
于 2015-05-25T14:09:28.167 回答