JSON输出文件格式

Question

I am using Canvasjs Charts to do my graphing from PHP / MySQL. Everything works as expected except for the creating of my JSON file.

Canvasjs requires the JSON file to look as follow:

callback({  
   "dps":
[{"division":"Xaxis VALUE","units":Yaxis VALUE}]
})

However, when creating my JSON file it is

[{"division":"Xaxis VALUE","units":Yaxis VALUE}]

All I want to know is how do I add the opening tag and closing tag in the sjon file from my script.

Here is the last part of my code that creates the JSON file:

$output_data= array();
    while($row = mysqli_fetch_array($result))
    {
        $output_data[] = array(
                                'division' => $row["division"],     
                                'units' => $row["units"]

                                );
    }

return json_encode($output_data, JSON_NUMERIC_CHECK);    
echo json_encode($output_data, JSON_NUMERIC_CHECK);   
}




$file_name = 'myresult2'.'.json';

if(file_put_contents($file_name, get_data()))
{
    echo $file_name. 'file created';
}
else
{
  echo 'Error';  
}

?>

Additional Data: This is the code that generates the graph.

<script>

var chart = null;
var dataPoints = [];

window.onload = function() {



chart = new CanvasJS.Chart("chartContainer", {
    animationEnabled: true,
    theme: "light",
    title: {
        text: "Graph Header"
    },
    axisY: {
        title: "% Verified",
        titleFontSize: 12,
        labelFontSize: 12,
        valueFormatString: "#.##%"      

    },
    axisX: {
        title: "Division",
        titleFontSize: 12,
        labelFontSize: 12
    },    
    data: [{
        type: "column",
        yValueFormatString: "#.##%",
        dataPoints: dataPoints
    }]
});


$.getJSON("myresult.json?callback=?", callback);    

}

function callback(data) {   
    for (var i = 0; i < data.dps.length; i++) {
        dataPoints.push({
            label: data.dps[i].division,
            y: data.dps[i].units
        });
    }
    chart.render(); 
}

</script>

Answer 1

Please try

// change this
$output_data[] = array(

// to this
$output_data['dps'][] = array(

Answer 2

What you need to do is enclose you created array in a new array with a key named dps .

So after your while loop you should do something like this

$json_data['dps']=$output_data;

return json_encode($json_data, JSON_NUMERIC_CHECK);