TreeView

A classic tree over a static data model: every level lives in one listing, and folders fold open in place.

with sc.TreeView('Distribution', {
    'A': {
        'B': None,        # a leaf
        'C': {},          # an empty folder
        'D': {'E': None, 'G': {}},
    }
}) as tree:
    ...

node = tree.value.get()

Properties: value, mode, directory, rows_visible, data.

Signals: value.on_change, on_navigate, on_submit.

The data model

data is one map from a name to a sub-map or None:

• a dict value is a folder; {} is an empty folder;
• None is a leaf;
• the map must have exactly one key, which is the root.

Node paths are the names joined with /, for example A/D/G. This is what the location bar shows, and what value contains.

An empty model ({} or None) lists no rows. A model can be handed in later.

Re-rooting

data is bindable. Setting a new model re-roots the tree and clears the selection, because the old paths belong to the old model:

tree.data.set(new_model)

The new model is validated on assignment, so a malformed one raises instead of drawing nothing.

Folding

A folder with children carries a chevron to the left of its row. Clicking it folds the folder open in place; clicking the row itself picks or ticks it. The two gestures are independent.

Multi-select

In the multi modes a folder stands for its whole subtree:

• ticking a folder drops any picks it covers, then adds it;
• once every child is picked, the picks fold into the folder itself;
• unticking a row inside a pick opens the pick one level at a time and leaves that row out.

A folder with only part of its subtree picked draws a half-ticked box.

Root behavior

.. is drawn only after leaving the root. Standing on the root, there is no outside to walk to.