Thanks for starting a new topic with these questions and for your patience in awaiting a response. Using taxonomies to filter gallery displays is a very common MLA application and it has generated several support topics over the years. There are links to some of these topics below, and you will see the range and variety of the solutions people have come up with.
You asked “Do I need categories att when I have media categories already identified to my images?” No, you can use your existing Media Categories taxonomy; there is nothing special about MLA’s Att. Categories and Att. Tags. They are provided as a convenience for users who don’t have existing taxonomies for their Media Library items.
As you can see in the Documentation tab, MLA provides two shortcodes modeled after some features WordPress provides as PHP functions: “MLA Tag Cloud Shortcode” and “MLA Term List Shortcode”. The example in your second post uses the tag cloud, but the term list is more appropriate for a hierarchical taxonomy.
The applications in the examples and earlier topics have two parts. First, a term list, tag cloud or search box that allows the user to specify one or more terms, and second, one or more [mla_gallery]
shortcodes to display a gallery of the selected term(s), often with pagination controls. Your example has both parts, but you have not added the parameters required to pass the selected term(s) from the term list/tag cloud to the gallery.
You can find simple examples that show passing term values to the gallery in the “Tag Cloud Pagination Example” and “MLA Term List Examples” sections of the Documentation tab. A good place to start would be to copy the example from the “MLA Term List Examples” section to a test page on your site and change all occurrences of attachment_category
to the slug for your Media Categories taxonomy. You can find that by hovering over the Media/Media Categories link in the admin menu and looking for the value of the taxonomy=
argument in the hyperlink. You can experiment with the example to get a better idea of how the system works.
You asked “Is it possible to create hierarchy gallery based on categories?” and then listed “Top page”, “Child page” and “Grandchild page”. There are many ways to organize something like this and I am not completely clear on how you imagine it would work. You can use the parent
parameter of the [mla_term_list]
shortcode to show only the root-level terms or the terms with a specific parent. A hierarchy gallery could be built from that.
You can find a number of application examples in these earlier topics and the other topics they link to:
Shortcode Display Help
keep selected dropdown value after submit (cookie, local storage ???)
Can a gallery be filtered by a dropdown and no submit button?
Is it possible to combine att tags dropdown + checkboxes?
Dropdown filter with two different taxonomies
Shortcode
Limiting search results to attachment tags/”Justifying” gallery grids
You will see that building an application around hierarchical taxonomies requires careful thought. MLA can help, but you will have to do some work to apply it to your specific ideas.
As I wrote in your earlier post, I am traveling for the remainder of this month. I regret that I cannot give you more specific help until my return, but I will do what I can when I’m back in the country. Thanks for your understanding and your patience.