需要帮助自动更新Google量规

问题描述 投票：1回答：1

我有点菜鸟，但我需要Google仪表的帮助，该仪表应该在数据库中获取最新条目并显示出来，同时自动更新而无需重新加载网站。现在我有显示它的代码，但是要使其更新为新值，我需要重新加载页面。请帮忙。这是我到目前为止的内容：

<html>
  <head>
   <script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>
   <script type="text/javascript">
      google.charts.load('current', {'packages':['gauge']});
      google.charts.setOnLoadCallback(drawChart);

      function drawChart() {

         var data = google.visualization.arrayToDataTable([
          ['Label', 'Value'],
          ['ProductPurity', <?php
$servername = "localhost";
$username = "u644759843_miki";
$password = "plantaze2020!";
$dbname = "u644759843_plantazeDB";

// Create connection
$conn = mysqli_connect($servername, $username, $password, $dbname);
// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

$sql = "SELECT ProductPurity FROM `Precizno ProductPurity` ORDER BY TimesStamp DESC LIMIT 1";
$result = mysqli_query($conn, $sql);

if (mysqli_num_rows($result) > 0) {
    // output data of each row
    while($row = mysqli_fetch_assoc($result)) {
        echo $row["ProductPurity"];
    }
} else {
    echo "0 results";
}

mysqli_close($conn);
?> ],

        ]);

        var options = {
          width: 400, height: 120,
          redFrom: 90, redTo: 100,
          yellowFrom:75, yellowTo: 90,
          minorTicks: 5
        };

        var chart = new google.visualization.Gauge(document.getElementById('chart_div'));

        chart.draw(data, options);

        setInterval(function() {
          data.setValue(0 ,1 , <?php


// Create connection
$conn = mysqli_connect($servername, $username, $password, $dbname);
// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

$sql = "SELECT ProductPurity FROM `Precizno ProductPurity` ORDER BY TimesStamp DESC LIMIT 1";
$result = mysqli_query($conn, $sql);

if (mysqli_num_rows($result) > 0) {
    // output data of each row
    while($row = mysqli_fetch_assoc($result)) {
        echo $row["ProductPurity"];
    }
} else {
    echo "0 results";
}

mysqli_close($conn);
?>
);
          chart.draw(data, options);
        }, 5000);
        setInterval(function() {
          data.setValue(1, 1, 40 + Math.round(60 * Math.random()));
          chart.draw(data, options);
        }, 5000);
        setInterval(function() {
          data.setValue(2, 1, 60 + Math.round(20 * Math.random()));
          chart.draw(data, options);
        }, 26000);
      }
    </script>
  </head>
  <body>
    <div id="chart_div" style="width: 400px; height: 120px;"></div>
  </body>
</html>

谢谢。

database charts google-visualization google-gauges
1个回答
0
投票

php在服务器上运行，因此每个页面加载仅运行一次。

要更新图表而不重新加载页面，您将需要将php与html / javascript分开。

将php本身保存到其他文件中。

您需要将其余数据包括在php中，包括列标题。

请参见以下PHP代码段。出于示例目的，我们将文件命名为-> getdata.php

<?php
  $servername = "localhost";
  $username = "u644759843_miki";
  $password = "plantaze2020!";
  $dbname = "u644759843_plantazeDB";

  // Create connection
  mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
  $conn = mysqli_connect($servername, $username, $password, $dbname);
  $conn->set_charset('utf8mb4');

  $sql = "SELECT ProductPurity FROM `Precizno ProductPurity` ORDER BY TimesStamp DESC LIMIT 1";
  $result = mysqli_query($conn, $sql);

  // create data array
  $data = [];
  $data[] = ["Label", "Value"];

  // output data of each row
  while($row = mysqli_fetch_assoc($result)) {
      $data[] = ["ProductPurity", $row["ProductPurity"]];
  }

  mysqli_close($conn);

  // write data array to page
  echo json_encode($data);
?>

接下来，将html / javascript保存到其自己的文件中。出于示例目的，我们将文件命名为-> chart.html

要从php获取数据，我们将使用jquery ajax。

请参见以下代码段...

<!DOCTYPE html>
<html lang="en">
  <head>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.0/jquery.min.js"></script>
    <script src="https://www.gstatic.com/charts/loader.js"></script>
    <script>
      google.charts.load('current', {
        packages: ['gauge']
      }).then(function () {
        var options = {
          width: 400, height: 120,
          redFrom: 90, redTo: 100,
          yellowFrom:75, yellowTo: 90,
          minorTicks: 5
        };

        var chart = new google.visualization.Gauge(document.getElementById('chart_div'));

        drawChart();

        function drawChart() {
          $.ajax({
            url: 'getdata.php',
            dataType: 'json'
          }).done(function (jsonData) {
            // use response from php for data table
            var data = google.visualization.arrayToDataTable(jsonData);
            chart.draw(data, options);

            // draw again in 5 seconds
            window.setTimeout(drawChart, 5000);
          });
        }
      });
    </script>
  </head>
  <body>
    <div id="chart_div" style="width: 400px; height: 120px;"></div>
  </body>
</html>
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