javascript - Google Charts API - 饼图不显示

Question

尝试让 Visualizations.PieChart 正常工作，但即使有数据，它也会绘制一个带有标题的空白白框。这是我的代码。

<div id="globalramdonut" class="globalramdonut"></div>


google.charts.load('current', {'packages':['corechart','gauge','line','controls','geochart']});
google.charts.setOnLoadCallback(drawAllCharts);

var ramdonutdata;
function setramdonutdata(){
    var query = "SELECT Location, SUM(RAMCapacityGB) AS 'RAM Capacity GB' FROM clusterstat WHERE Date = (SELECT MAX(Date) FROM clusterstat) GROUP BY Location ASC";
    //encode the query so we can submit it via URL.
    var urlencoded = encodeURI(sql2json+query);
    // get the data returned from 'urlencoded'
    var jsonData = $.ajax({
        url: urlencoded,
        dataType: "json",
        async: false
    }).responseText;
    console.log(urlencoded);
    // assign a google DataTable object 
    ramdonutdata = new google.visualization.DataTable(jsonData);
}

function drawRamDonut(){
    setramdonutdata();

    var options = {
        title: 'RAM Capacity by Location',
        pieHole: 0.4,
        sliceVisibilityThreshold: 0
    };

    var chart = new google.visualization.PieChart(document.getElementById('globalramdonut'));
    chart.draw(ramdonutdata,options);
}

function drawAllCharts(){
    drawRamDonut();
}

这是从我的 PHP 脚本返回的数据......

{"cols":[{"label":"Location","type":"string"},{"label":"RAM Capacity GB","type":"number"}],"rows":[{"c":[{"v":"Amsterdam"},{"v":"12286.34"}]},{"c":[{"v":"Argentina"},{"v":"383.97"}]},{"c":[{"v":"Belgium"},{"v":"8189.33"}]},{"c":[{"v":"Brazil"},{"v":"2047.59"}]},{"c":[{"v":"California"},{"v":"14523.22"}]},{"c":[{"v":"Guadalajara"},{"v":"767.90"}]},{"c":[{"v":"Hong Kong"},{"v":"4351.54"}]},{"c":[{"v":"Massachusetts"},{"v":"3647.56"}]},{"c":[{"v":"Ontario"},{"v":"383.97"}]},{"c":[{"v":"Oregon"},{"v":"174896.81"}]},{"c":[{"v":"Shanghai"},{"v":"1279.90"}]},{"c":[{"v":"South Korea"},{"v":"383.19"}]},{"c":[{"v":"Tennessee"},{"v":"3327.52"}]},{"c":[{"v":"Texas"},{"v":"1535.64"}]},{"c":[{"v":"Tokyo"},{"v":"719.64"}]},{"c":[{"v":"Virginia"},{"v":"44882.59"}]}]}

感谢您的阅读。

Answer 1

首先，“RAM 容量 GB” 列的值必须是数字，而不是字符串。
(去掉引号)

{"c":[{"v":"阿姆斯特丹"},{"v":12286.34}]}

而不是...

{"c":[{"v":"阿姆斯特丹"},{"v":"12286.34"}]}

这应该使图表出现......

另外强烈建议不要在$.ajax调用中使用async: false

相反，使用done回调

建议设置类似于以下工作片段...

• 使用真实网址时将 fail 替换为 done
• 您可以将 Google 回调放在 load 语句中

google.charts.load('current', {
  callback: function () {
    var query = "SELECT Location, SUM(RAMCapacityGB) AS 'RAM Capacity GB' FROM clusterstat WHERE Date = (SELECT MAX(Date) FROM clusterstat) GROUP BY Location ASC";

    //var urlencoded = encodeURI(sql2json+query);

    $.ajax({
      url: 'test', //urlencoded
      dataType: 'json'
    }).fail(function (jsonData) {  // <-- change 'fail' to 'done'

      // remove following when using with 'done'
      jsonData = {
        "cols":[
          {"label":"Location","type":"string"},
          {"label":"RAM Capacity GB","type":"number"}
        ],
        "rows":[
          {"c":[{"v":"Amsterdam"},{"v":12286.34}]},
          {"c":[{"v":"Argentina"},{"v":383.97}]},
          {"c":[{"v":"Belgium"},{"v":8189.33}]},
          {"c":[{"v":"Brazil"},{"v":2047.59}]},
          {"c":[{"v":"California"},{"v":14523.22}]},
          {"c":[{"v":"Guadalajara"},{"v":767.90}]},
          {"c":[{"v":"Hong Kong"},{"v":4351.54}]},
          {"c":[{"v":"Massachusetts"},{"v":3647.56}]},
          {"c":[{"v":"Ontario"},{"v":383.97}]},
          {"c":[{"v":"Oregon"},{"v":174896.81}]},
          {"c":[{"v":"Shanghai"},{"v":1279.90}]},
          {"c":[{"v":"South Korea"},{"v":383.19}]},
          {"c":[{"v":"Tennessee"},{"v":3327.52}]},
          {"c":[{"v":"Texas"},{"v":1535.64}]},
          {"c":[{"v":"Tokyo"},{"v":719.64}]},
          {"c":[{"v":"Virginia"},{"v":44882.59}]}
        ]
      };

      var ramdonutdata = new google.visualization.DataTable(jsonData);

      var options = {
        title: 'RAM Capacity by Location',
        pieHole: 0.4,
        sliceVisibilityThreshold: 0
      };

      var chart = new google.visualization.PieChart(document.getElementById('globalramdonut'));
      chart.draw(ramdonutdata,options);
    });
  },
  packages: ['corechart']  // removed unused packages
});

<script src="https://www.gstatic.com/charts/loader.js"></script>
<script src="https://code.jquery.com/jquery-1.12.4.js"></script>
<div id="globalramdonut" class="globalramdonut"></div>