Javascript“预期对象”使用 Google Visualization API 时

Question

大家好，我正在创建一个小类来帮助我使用 Google 可视化 API。您可以在此处查看其工作原理...

http://code. google.com/apis/visualization/documentation/gallery/annotatedtimeline.html

这是谷歌的实现。

google.load('visualization', '1', {'packages':['annotatedtimeline']});
      google.setOnLoadCallback(drawChart);
      function drawChart() {
        var data = new google.visualization.DataTable();
        data.addColumn('date', 'Date');
        data.addColumn('number', 'Sold Pencils');
        data.addColumn('string', 'title1');
        data.addColumn('string', 'text1');
        data.addColumn('number', 'Sold Pens');
        data.addColumn('string', 'title2');
        data.addColumn('string', 'text2');
        data.addRows([
          [new Date(2008, 1 ,1), 30000, undefined, undefined, 40645, undefined, undefined],
          [new Date(2008, 1 ,2), 14045, undefined, undefined, 20374, undefined, undefined],
          [new Date(2008, 1 ,3), 55022, undefined, undefined, 50766, undefined, undefined],
          [new Date(2008, 1 ,4), 75284, undefined, undefined, 14334, 'Out of Stock','Ran out of stock on pens at 4pm'],
          [new Date(2008, 1 ,5), 41476, 'Bought Pens','Bought 200k pens', 66467, undefined, undefined],
          [new Date(2008, 1 ,6), 33322, undefined, undefined, 39463, undefined, undefined]
        ]);

        var chart = new google.visualization.AnnotatedTimeLine(document.getElementById('chart_div'));
        chart.draw(data, {displayAnnotations: true});

这是我制作的课程，但我遇到了问题。 对于我想要做的事情来说，该类使向图表添加数据变得更加容易和更好。基本上，该类不会为您创建具有一堆未定义值的列，而是为您做这件事，并且您不必跟踪每列的位置/值。

 function GraphManager(dataTable)
 {
     this.graphData = new Array();
     this.dataTable = dataTable;

     this.titleFinder = new Object(); // used to keep track of the indices

     this.dataTable.addColumn('date', 'Date');

     this.addSet = function(title)
     {

         var setCount = (this.dataTable.getNumberOfColumns() -1) / 3; //used for the column name
         var place = this.dataTable.getNumberOfColumns(); 

         this.titleFinder[title] = place; //the title of the column and its location

         this.dataTable.addColumn('number', title);
         this.dataTable.addColumn('string', 'title' + setCount);
         this.dataTable.addColumn('string', 'text' + setCount); 

     }

     this.addPoint = function(title, date, number)
     {
         //this function finds the location of the category
         //and inserts a column with data at the location


         var place = titleFinder[title]; //get the location

         var column = new Array(dataTable.getNumberOfColumns()); 
         column[0] = date;
         column[place] = number;

         for (var i = 0;i<place; i++)
         {
            column[i] = undefined; 
         }

         for (var i = place + 1; i<dataTable.getNumberOfColumns(); i++)
         {
             column[i] = undefined;
         }

         var next = this.graphData.length;
         this.graphData[next] = column;
         data.addRows(graphData);

     }


 }

然后这段代码可以用更少的代码完成同样的事情。 函数 printGraph() { var data = new google.visualization.DataTable();

     var gm = new GraphManager(data);
     var title = "testcategory";


     gm.addSet(title);
     gm.addPoint(title, new Date[2010, 5, 10], 100);
     gm.addPoint(title, new Date[2010, 6, 10], 200);


     var chart = new google.visualization.AnnotatedTimeLine(document.getElementById('chart_div'));
     chart.draw(gm.dataTable, {displayAnnotations: true});

问题

对于这个 HTML 正文，

<input type="button" onclick="printGraph()" value="Draw Graph">
<div id='chart_div' style='width: 800px; height: 350px;'></div>

是：我在 gm.addSet(title) 行上收到“预期对象”错误。基本上，我无法使用 GraphManager 类。我在这里做错了什么？

Answer 1

我不知道，按照：

http://code.google.com/apis/visualization/documentation/reference.html#DataTable

count 不是一个属性，但我看到您在代码中的很多地方都提到了它：

var column = new Array(dataTable.count)

但是有 dataTable.getNumberOfColumns()

Answer 2

好的，我找到了问题所在。基本上我遗漏了一堆“this”语句，当我创建一个新日期时，我使用了括号而不是圆括号。我还意识到，当我添加一组新数据时，我需要遍历旧数据来添加空列。如果有人感兴趣的话，这里是完成的代码...如果您要在不同日期添加数据或者您不知道将拥有多少个数据集，那么它非常有用。

 function GraphManager(adataTable)
 {
     this.graphData = new Array();
     this.dataTable = adataTable;

     this.titleFinder = new Object(); // used to keep track of the indices

     this.dataTable.addColumn('date', 'Date');

     this.addSet = function(title)
     {

         var setCount = (this.dataTable.getNumberOfColumns() -1) / 3; //used for the column name
         var pointsCount = this.graphData.length;
         var place = this.dataTable.getNumberOfColumns();

         this.titleFinder[title] = place; //the title of the column and its location

         this.dataTable.addColumn('number', title);
         this.dataTable.addColumn('string', 'title' + setCount);
         this.dataTable.addColumn('string', 'text' + setCount);

         var newCount = this.dataTable.getNumberOfColumns();



         for (var i = 0; i<pointsCount; i++)
         {
             for (var j=place; j<newCount; j++)
             {
                 this.graphData[i][j] = undefined;
             }


         }  

     }

     this.addPoint = function(title, date, number)
     {
         //this function finds the location of the category
         //and inserts a column with data at the location


         var place = this.titleFinder[title]; //get the location

         var column = new Array(this.dataTable.getNumberOfColumns()); 
         column[0] = date;
         column[place] = number;

         for (var i = 1;i<place; i++)
         {
            column[i] = undefined; 
         }

         for (var i = place + 1; i<this.dataTable.getNumberOfColumns(); i++)
         {
             column[i] = undefined;
         }

         var next = this.graphData.length;
         this.graphData[next] = column;
         this.dataTable.addRows(this.graphData);

     }


 }

它的使用方法如下：

     var data = new google.visualization.DataTable();
     var gm = new GraphManager(data);

     var title = "testcategory";
     var title2 = "cat";

     gm.addSet(title);
     gm.addPoint(title, new Date(2010, 5, 10), 100);
     gm.addPoint(title, new Date(2010, 6, 10), 200);
     gm.addPoint(title, new Date(2010, 2, 10), 300);


     gm.addSet(title2);
     gm.addPoint(title2, new Date(2010, 6, 10), 100);
     gm.addPoint(title2, new Date(2010, 2, 10), 500);

     var chart = newgoogle.visualization.AnnotatedTimeLine(document.getElementById('chart_div'));
     chart.draw(gm.dataTable, {displayAnnotations: true});

Answer 3

不应该是“dataTable”而不是“tableData”吗？

for (var i = place + 1; i<tableData.count; i++)
{
    column[i] = undefined;
}