Chart.js -在一个页面上创建多个图表 - Chart.js - Creating multiple charts on one page

我想在我的joomla组件"bestia"中使用chart.js。为此，我导入了chart.js作为manifest.xml中的media-element。

我通过以下方式调用js:

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

现在我想使用一个助手来缩短一些事情。我的助手应该画一个图…

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;
    }
}

如果我调用这个Jhtml-Graphs，图形就会正确呈现:

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

但是如果我想添加第二个图形到我的页面，第一个图形不再显示:

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

我能做什么?

您正在重新声明window.onload函数。这就是为什么你只能画一张(最后一张)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 }); 
}

你能做些什么来解决这个问题?我建议更改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); ?>

在底部某处你必须调用new function:

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