You will need a block type created and installed already. In this recipe, we are going to add a template to the block type that we created at the beginning of the chapter.

The steps for creating custom block templates are as follows:

You can specify alternative templates right from the block controller, so you can automatically render a different template depending on certain settings, conditions, or just about anything you can think of. Simply use the render() function in a callback that gets called before the view is rendered.

public function view() {
  $this->render('templates/no_title');
}

This will use the no_title.php file instead of view.php to render the block. Notice that adding the .php file extension is not required. Just like the block's regular view.php file, developers can include view.css and view.js files in their template directories to have those files automatically included on the page.