Chart.js - 在一个页面上创建多个图表

Question

我想在名为“bestia”的joomla组件中使用chart.js 。 为此，我在manifest.xml中将chart.js导入为media-element。

我通过执行以下操作来调用js：

JHtml::script(Juri::root() . 'media/com_hostinghelden/chartjs/Chart.js');

现在我想使用帮助器缩短一些东西。 我的帮手应画一张图...

abstract class JHtmlGraphs 
{
    public function draw($title = NULL, $labelset = NULL, $data = NULL, $data2 = NULL)
    {
        $script = "<script> var barChartData_$title = { labels : [ {$labelset} ], datasets : [ { fillColor : 'rgba(220,220,220,0.5)', strokeColor : 'rgba(220,220,220,0.8)', highlightFill: 'rgba(220,220,220,0.75)', highlightStroke: 'rgba(220,220,220,1)', data : [ $data ] }, { fillColor : 'rgba(151,187,205,0.5)', strokeColor : 'rgba(151,187,205,0.8)', highlightFill : 'rgba(151,187,205,0.75)', highlightStroke : 'rgba(151,187,205,1)', data : [ $data2 ] } ] }; window.onload = function(){ var ctx_$title = document.getElementById('canvas_$title').getContext('2d'); window.myBar = new Chart(ctx_$title).Bar(barChartData_$title, { responsive : true }); } </script>";
        $canvas = "<div style='width: 100%'><canvas id='canvas_$title' height='20' width='20'></canvas></div>";
        return $script . $canvas;
    }
}

好吧，如果我调用这个Jhtml-Graphs，图表会正确呈现：

<?php echo JHtml::_('graphs.draw', "Titel", $labelset, $data, $data2);  ?>

但是，如果我想在页面中添加第二个图表，则不再显示第一个图表：

<?php echo JHtml::_('graphs.draw', "Titel2", $labelset, $data, $data2); ?>

我能做什么？

Answer 1

您正在重新声明window.onload函数。 这就是为什么你只画一张（最后）图表。

window.onload = function(){ 
    var ctx_$title = document.getElementById('canvas_$title').getContext('2d');                                    
    window.myBar = new Chart(ctx_$title).Bar(barChartData_$title, { responsive : true }); 

}

你可以做些什么来解决这个问题。 我建议改变JHtmlGraphs类如下：

    abstract class JHtmlGraphs 
{
    private $titles = array();

    public function draw($title = NULL, $labelset = NULL, $data = NULL, $data2 = NULL)
    {
        $script = "<script> var barChartData_$title = { labels : [ {$labelset} ], datasets : [ { fillColor : 'rgba(220,220,220,0.5)', strokeColor : 'rgba(220,220,220,0.8)', highlightFill: 'rgba(220,220,220,0.75)', highlightStroke: 'rgba(220,220,220,1)', data : [ $data ] }, { fillColor : 'rgba(151,187,205,0.5)', strokeColor : 'rgba(151,187,205,0.8)', highlightFill : 'rgba(151,187,205,0.75)', highlightStroke : 'rgba(151,187,205,1)', data : [ $data2 ] } ] };</script>";
        $canvas = "<div style='width: 100%'><canvas id='canvas_$title' height='20' width='20'></canvas></div>";

        $this->titles[] = $title; //storing titles
        return $script . $canvas;
    }

    public function finishDrawing() {
        $launchCharts = '';
        foreach($this->titles as $title) {
            $launchCharts .= "var ctx_$title = document.getElementById('canvas_$title').getContext('2d'); window.myBar_$title = new Chart(ctx_$title).Bar(barChartData_$title, { responsive : true });";
        }
        $this->titles = array();

        $script =  "<script>window.onload = function(){ $launchCharts }</script>";
        return $script;
    }
}

我修改了你的脚本。 现在，您的onload函数将从finishDrawing方法生成一次：

<?php echo JHtml::_('graphs.draw', "Titel", $labelset, $data, $data2);  ?>
<?php echo JHtml::_('graphs.draw', "Titel2", $labelset, $data, $data2); ?>

在底部的某个地方你必须调用新函数：

<?php echo JHtml::finishDrawing(); //you better know than me how to call this function?>