Question

我正在构建一个监视应用程序服务器上运行的服务数量的应用程序。有关正在运行的服务的信息将存储在数据库中，我想在网页上显示一些该信息。此时，我只想构建一个主动运行的服务数量的图形表示，这些服务在数据库更新时动态更新。目标是创建一个简单的图表，显示运行的服务数量的最新10（左右）值，类似于ekg读数的样子。我正在使用dojox.charting.Chart小部件，但我无法正确更新图表，因此它只显示numFailedAttempts的十个最新值：＆＃34; 0＆＃34;。就像现在一样，图表显示所有值，并且x轴值不断地越来越近，以适应所有事物。根据dojo api参考和dojotoolkit.org上的文档，我认为＆＃34; displayRange＆＃34; dojox.charting.Chart的属性应该解决这个问题。所以我的问题是，我做错了什么？这是代码：

<html>
<head>        
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">        
    <link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/dojo/1.6/dojo/resources/dojo.css">        
    <script src="http://ajax.googleapis.com/ajax/libs/dojo/1.6.0/dojo/dojo.xd.js" data-dojo-config="isDebug: true, parseOnLoad: true"></script>

    <script type="text/javascript">

        dojo.require("dojox.charting.StoreSeries");
        dojo.require("dojox.charting.Chart2D");
        dojo.require("dojo.store.Memory");
        dojo.require("dojo.store.Observable");
        dojo.require("dojox.charting.Chart");
        dojo.require("dojox.charting.plot2d.Areas");

        dojo.ready(function(){renderDataChart()});

        function renderDataChart(){

            //data from a database
            var dataChartData = {
                itentifier: 'id',
                items:
                    [
                    {id: 1, serviceName:"service1", startDate:"today", endDate:"today", numFailedAttempts:"1", errorTime:"null", errorMessage:"null", suppressError:"null"},
                    {id: 2, serviceName:"service2", startDate:"today", endDate:"today", numFailedAttempts:"1", errorTime:"now", errorMessage:"broken", suppressError:"click"},
                    {id: 3, serviceName:"service3", startDate:"today", endDate:"today", numFailedAttempts:"0", errorTime:"now", errorMessage:"broken", suppressError:"click"},
                    {id: 4, serviceName:"service4", startDate:"today", endDate:"today", numFailedAttempts:"1", errorTime:"now", errorMessage:"broken", suppressError:"click"},
                    {id: 5, serviceName:"service5", startDate:"today", endDate:"today", numFailedAttempts:"0", errorTime:"null", errorMessage:"null", suppressError:"null"}
                ]                    
            };
            //data store
            var dataChartStore = dojo.store.Observable(new dojo.store.Memory({
                data: {
                    identifier: "id",
                    label: "runningServices",
                    items: dataChartData
                }
            }));    

            var dataChart = new dojox.charting.Chart("myDataChart", {

                displayRange: 10,
                stretchToFit: false,
                scrolling: true,     
                fieldName: "runningServices",
                type: dojox.charting.plot2d.Areas
            });
            dataChart.addAxis("x", {microTickStep: 1, minorTickStep: 1});
            dataChart.addAxis("y", {vertical: true, minorTickStep: 1, natural: true});
            dataChart.addSeries("y", new dojox.charting.StoreSeries(dataChartStore, {query: {numFailedAttempts: 0}}, "value"));
            dataChart.render();

            //update datastore to simulate new data
            var startNumber = dataChartData.length;
            var interval = setInterval(function(){
                 dataChartStore.notify({value: Math.ceil(Math.random()*29), id: ++startNumber, numFailedAttempts: 0});                    

            }, 1000);
        }
    </script>
</head>
<body>
    <div id="myDataChart" style="width: 500px; height: 200px;"></div>
</body>

Answer 1

我一直在努力解决同样的问题。我还没有完全弄明白，但我找到了一个替代方案，可以做我认为你所描述的内容。这是代码（下面的解释）：

<html>
<head>        
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">        
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/dojo/1.6/dojo/resources/dojo.css">        
<script src="http://ajax.googleapis.com/ajax/libs/dojo/1.6.0/dojo/dojo.xd.js" data-dojo-config="isDebug: true, parseOnLoad: true"></script>

<script type="text/javascript">

  dojo.require("dojox.charting.StoreSeries");
  dojo.require("dojo.store.Memory");
  dojo.require("dojo.store.Observable");

  dojo.require("dojox.charting.Chart2D");
  dojo.require("dojox.charting.Chart");
  dojo.require("dojox.charting.plot2d.Areas");

  dojo.ready(function () {
    renderArrayChart();
    renderStoreChart();
  });

  function renderArrayChart() {
    try {
      var dataChart = new dojox.charting.Chart("myArrayChart", {
        stretchToFit: false,
        scrolling: false,
        type: dojox.charting.plot2d.Areas,
        title: "update array, rerender"
      });

      // create an array of x/y pairs as the data source
      var data = [{ x: 1, y: 2.1}];

      dataChart.addAxis("x", { microTickStep: 1, minorTickStep: 1 });

      // set min/max so the Y axis scale does not change with the data
      dataChart.addAxis("y", { vertical: true, minorTickStep: 1, natural: true, min: 0, max: 30 });

      // create the series with the data array as the source
      dataChart.addSeries("y", data);
      dataChart.render();

      // this counter is used as the x value for new data points
      var startNumber = data.length;

      //update datastore to simulate new data
      var interval = setInterval(function () {

        // if we have more than 9 data points in the array, remove the first one
        if (data.length > 9) data.splice(0, 1);

        // push a new data point onto the array using the counter as the X value
        data.push({ x: ++startNumber, y: Math.ceil(Math.random() * 29) });

        // update the series with the updated arrray
        dataChart.updateSeries("y", data);

        // re-render the chart
        dataChart.render();

      }, 1000);
    }
    catch (ex) {
      alert(ex.message);
    }
  }


  function renderStoreChart() {
    try {
      // create an array as the data source
      var dataArray = [{ id: 1, value: 2.1}];

      // create the observable data store
      var dataStore = dojo.store.Observable(new dojo.store.Memory({
        data: {
          identifier: "id",
          items: dataArray
        }
      }));

      var storeChart = new dojox.charting.Chart("myStoreChart", {
        stretchToFit: false,
        scrolling: false,
        type: dojox.charting.plot2d.Areas,
        title: "data store"
      });

      storeChart.addAxis("x", { microTickStep: 1, minorTickStep: 1 });

      // set min/max so the Y axis scale does not change with the data
      storeChart.addAxis("y", { vertical: true, minorTickStep: 1, natural: true, min: 0, max: 30 });

      storeChart.addSeries("y", new dojox.charting.StoreSeries(dataStore, { bindings: { x: "id", y: "value"} }));
      storeChart.render();

      // this counter is used as the x value for new data points
      var startNumber = 1;

      //update datastore to simulate new data
      var interval = setInterval(function () {

        // if we have more than the desired number data points in the store, remove the first one
        if (startNumber > 9) dataStore.notify(null, startNumber - 10);

        // add a new point to the data store
        dataStore.notify({ id: ++startNumber, value: Math.ceil(Math.random() * 29) });

      }, 1000);
    }
    catch (ex) {
      alert(ex.message);
    }
  }

</script>
</head>
<body>
<div id="myArrayChart" style="width: 500px; height: 200px;"></div><br />
<div id="myStoreChart" style="width: 500px; height: 200px;"></div>
</body>
</html>

顶部图表使用简单数组作为数据源（而不是Observable商店）。在区间函数中，它只是切片第一个数组元素（在达到所需数量的元素之后）并添加一个新元素。然后它更新系列（dataChart.updateSeries），然后重新呈现图表。为了使X轴标签正常工作，每个数组项都是对象x和y值（例如{x：1，y：2.1}）。

底部图表使用数据存储（适用于您的示例）。它确实使数据滚动出图表。 dataStore.notify（null，objectId）方法将从数据存储中删除具有给定id的对象。但是，此图表上的X轴标签仍无法正确显示。

在任何一种情况下，图表都不能很好地扩展。即使只有大约50个数据点，渲染也会变得很慢。我可能会尝试查看其他选项，例如Flot - 这些选项似乎在使用大量数据点时表现更好。

dojox.charting.Chart dataRange没有正确限制图表x轴

1 个答案: