Hierarchical tree with bubble up, cascade and folder selection capabilities

Question

I'm looking for a way to show multi-selection hierarchical component (perhaps a tree) which allow selecting either leafs or folders, with both bubble-up and cascade functionality.

Lets say I use some folder hierarchy:

I'm thinking about 4-states checkbox (select without children -> select with children -> select only children -> unselect).

Any better solution?

I've seen this question but none of the answers fit :(

Edit: relating to each solution in the similar question:

1. I cannot use a map as it is not location based hierarchy.
2. Adding another leaf for selecting parent only is OK, but it duplicates entries and may increase the tree size.
3. Miller columns doesn't solve this issue.
4. Adding "select all" button on hover doesn't fix touch devices. Also it looks too complicated to me.

Answer 1

Quick thought (I do not pretend to give the answer, but just some brainstorming): combine your proposal 2 & 4: for every list of descendants (at any level), add an extra child on top stating 'select all child elements. ( Rather then 'child elements', you should use the actual name, like 'cities', 'elephants' or bananas. )

You might consider sticking to just two states for your checkboxes, 'checked' and 'empty'. By doing so, you make it clear that every checkbox refers to JUST the item behind it.

Answer 2

This is a common pattern you see in multiselect tree hierarchy. It is most easily seen in microsoft installation interface when selecting languages ...etc.

The following is from google drive:

Basically you provide a third icon [-] that shows that child is selected.

Microsoft also had different shading for the checks to show if all children were selected or only some. And you could toggle between the states by clicking on the parent. Clicking the parent also gave clearly labeled instructions