在本章中，我们将展示使用Google Chart API绘制图表所需的配置.
使用Google图表库创建一个HTML页面.
googlecharts_configuration.htm
<html>
<head>
<title>Google Charts Tutorial</title>
<script type = "text/javascript" src = "https://www.gstatic.com/charts/loader.js">
</script>
<script type = "text/javascript">
google.charts.load('current', {packages: ['corechart']});
</script>
</head>
<body>
<div id = "container" style = "width: 550px; height: 400px; margin: 0 auto">
</div>
</body>
</html>此处容器 div用于包含使用Google Chart库绘制的图表.这里我们使用google.charts.load方法加载最新版本的corecharts API.
Google Chart库使用非常使用json语法的简单配置.
// Instantiate and draw the chart.
var chart = new google.visualization.PieChart(document.getElementById('container'));
chart.draw(data, options);此处数据表示json数据，而options表示Google Chart库使用draw()方法绘制带有容器div的图表的配置.现在我们将配置各种参数来创建所需的json字符串.
配置图表的选项.
// Set chart options
var options = {'title':'Browser market shares at a specific website, 2014',
'width':550,
'height':400};配置要在图表上显示的数据. DataTable是一个特殊的表结构集合，包含图表的数据.数据表的列表示图例，行表示相应的数据. addColumn()方法用于添加列，其中第一个参数表示数据类型，第二个参数表示图例. addRows()方法用于相应地添加行.
// Define the chart to be drawn.
var data = new google.visualization.DataTable();
data.addColumn('string', 'Browser');
data.addColumn('number', 'Percentage');
data.addRows([
['Firefox', 45.0],
['IE', 26.8],
['Chrome', 12.8],
['Safari', 8.5],
['Opera', 6.2],
['Others', 0.7]
]);// Instantiate and draw the chart.
var chart = new google.visualization.PieChart(document.getElementById('container'));
chart.draw(data, options);以下是完整示例 :
googlecharts_configuration.htm
<html>
<head>
<title>Google Charts Tutorial</title>
<script type = "text/javascript" src = "https://www.gstatic.com/charts/loader.js">
</script>
<script type = "text/javascript">
google.charts.load('current', {packages: ['corechart']});
</script>
</head>
<body>
<div id = "container" style = "width: 550px; height: 400px; margin: 0 auto">
</div>
<script language = "JavaScript">
function drawChart() {
// Define the chart to be drawn.
var data = new google.visualization.DataTable();
data.addColumn('string', 'Browser');
data.addColumn('number', 'Percentage');
data.addRows([
['Firefox', 45.0],
['IE', 26.8],
['Chrome', 12.8],
['Safari', 8.5],
['Opera', 6.2],
['Others', 0.7]
]);
// Set chart options
var options = {'title':'Browser market shares at a specific website, 2014', 'width':550, 'height':400};
// Instantiate and draw the chart.
var chart = new google.visualization.PieChart(document.getElementById ('container'));
chart.draw(data, options);
}
google.charts.setOnLoadCallback(drawChart);
</script>
</body>
</html>以下代码调用drawChart函数在Google Chart库完全加载时绘制图表.
google.charts.setOnLoadCallback(drawChart);
验证结果.
