I'm designing navigation for standard landscape/split view in iPad and the idea is to make the left side menu a multilevel one, so the user could compare data values on the right side between different levels. Is there any savy way to show such multilevel menu or am I doomed to picker or drill downs? Also if you know of any such component already available online I would very much appreciate the link as it could speed up dev team work too.
A Material Design execution of a multi level accordion menu can be found on the Polymer Project site (mobile view).
If it's any more complicated than that, then you probably have to look at the app structure. What would be an example of a sample page and content?
There are some examples of using custom controls for the menu. One of these can be Feedly where – although related to content this time – sublevels are presented as a dropdown, and the menu is scroll-enabled to fit all the contents.
You can also show a path to the place where User is at the moment – something that Amazon app tries to achieve (although not clearly telling the User that what they see are the parent levels of the selected category.
One more idea is adapting this kind of menu:
You can find it here. I have no idea why it is reversed (a deeper level appears on the left of the parent level) but once reversed it could be one of the directions for you to go. It reminds me a little bit the navigation that Spotify had a time ago (yet it was completely content based):