Is it possible to add a custom button (with a custom action, of course) to the JToolbar of a standard Joomla 3 component (com_contents) without modifying the original source code?
Background: I need to add a button to the
com_contents main screen (the list of all the articles) to create a massive mail function. I can, of course, modify the standard Joomla files, but if I modify it, when I upgrade Joomla to a new version I'll lose my customization. But, if somehow I can add the button, I won't lose any change when updating...
And if it's possible to do this, how can it be done? Creating a plugin? Is there any tutorial to guide me thru the creation of this addon?