[ENHANCMENT] TreeView selection control features

[EliteMasterEric]

When looking through the documentation and code for the TreeView component (which I am aware is experimental) I noticed that several missing features (or very poorly documented features) prevent the TreeView from being useful for user input, or anything more than display of a list of nodes.

The primary three I am looking for are:

• Either property of TreeViewNode which determines whether it is the currently the selected item of its TreeView, or a property of TreeView which determines which item is selected (acting similarly to the ListView component)
• A property of TreeViewNode which determines whether it is allowed to be the selected element of a TreeView.
• An event callback for TreeView which triggers when an item is selected, and/or an event callback for TreeViewNode which triggers when it is selected.

The implementation of these three features would allow for user interaction with the TreeView to act as an input for the rest of the application, by allowing the user to select a node from the tree to "act upon".

A common use case for this feature would be a tree view which displays a directory structure, with the leaf nodes being individual files. The user could click on a leaf node to select a specific file.

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As an aside, one potential additional feature (which I do not need for my application but may be needed in the future) is implementing the SelectionMode property on the TreeView, to allow the developer to define in what manner one (or more) list items may be selected, as seen in the ListView component.

haxeui-core/haxe/ui/containers/ListView.hx

Line 225 in d67dc45

switch (_listview.selectionMode) {

This may be a more complicated feature to implement, as multi-selection may have more advanced rules for a tree view (should the user only be allowed to multi-select nodes with the same parent? or only nodes on the same "level"?), so it might be better set aside as its own issue.

[ianharrigan]

Either property of TreeViewNode which determines whether it is the currently the selected item of its TreeView, or a property of TreeView which determines which item is selected (acting similarly to the ListView component)

I think you are after .selectedNode on the treeview

A property of TreeViewNode which determines whether it is allowed to be the selected element of a TreeView.

Do you mean like a disabled property? I mean, all nodes are currently selectable.

An event callback for TreeView which triggers when an item is selected, and/or an event callback for TreeViewNode which triggers when it is selected.

TreeView should dispatch a UIEvent.CHANGE

[EliteMasterEric]

I think you are after .selectedNode on the treeview
TreeView should dispatch a UIEvent.CHANGE

These should work, thank you. Sorry, I had trouble finding these things in the documentation. Maybe adding a simple trace() call to the UI explorer could be something to add to the list?

Also, does setting .selectedNode via code (to forcibly select an item) work?

Do you mean like a disabled property? I mean, all nodes are currently selectable.

Yes, I was thinking of doing selectable="false" but disabled makes sense too.

[ianharrigan]

Also, does setting .selectedNode via code (to forcibly select an item) work?

Yeah, its bi directional... maybe i should start enhancing all the component explorer components with some more "options" rather than just "disable"... I mean, the test app for treeview (when i was working out its native counter part) was pretty comprehensive: https://community.haxeui.org/uploads/default/original/1X/d6937fecb3fcfde249b91b8dc54939a85f64421f.gif

Maybe i should start doing things like that in the component explorer also. Ill have a think about selectable, it might be a useful addition, im just not entirely sure when it would be useful (ie, disabled at least will give visual feedback that you cant do something).

Cheers,
Ian