PHP Class Piwik\Plugins\ExamplePlugin\Widgets\MyExampleWidget
To configure a widget simply call the corresponding methods as described in the API-Reference:
http://developer.piwik.org/api-reference/Piwik/Plugin\Widget
As long as you return a string everything is fine. You can use for instance a "Piwik\View" to render a
twig template. In such a case don't forget to create a twig template (eg. myViewTemplate.twig) in the
"templates" directory of your plugin.