How to display TreeView backed by a Vec of Rust objects

[gtk-rs]

How to display TreeView backed by a Vec of Rust objects

[GuillaumeGomez]

I used sortable trees in process-viewer and bound the sorting to "hidden" columns. Here are the lines that might be interesting for you: https://github.com/GuillaumeGomez/process-viewer/blob/15e9252f096f831adda747cb693f0d5c27c1ecab/src/display_procs.rs#L66-L75 and https://github.com/GuillaumeGomez/process-viewer/blob/15e9252f096f831adda747cb693f0d5c27c1ecab/src/display_procs.rs#L177-L180

[kornelski]

But this is the thing I'm struggling with: you're storing the data in the ListStore. I have my data in a Vec.

You're filling the store once, fully, with insert_with_values, and don't seem to update later.

But if vec[7] changed in my program, how do I know where vec[7]'s data is in the TreeView? which cell do I update?

[GuillaumeGomez]

I actually do here: https://github.com/GuillaumeGomez/process-viewer/blob/15e9252f096f831adda747cb693f0d5c27c1ecab/src/process_viewer.rs#L100-L116

[kornelski]

So that's a linear search. It's going to be O(n^2) for me, because in my program I emit an event "7th row of the Vec changed, 3rd row of the Vec changed, 11th row of the Vec changed". If I use a treeiter to scan through entire store every time to find where my Vec's data ended up in, it'll be super slow.

I have my expectations set by Cocoa, where I can say "treeview.column1.text binds to mymodel.field1" and vec[7].field1.set() sends a message to treeview.column1 to update itself.

but here I have column.add_attribute(&cell, "text", 0); where 0 is the column number, not name of the field in the model.

[GuillaumeGomez]

You can try the other way around: using a vec of references to the liststore. Then no need to have the data twice.

[kornelski]

Does the TreeIter survive sorting? i.e. if it was iter of 0th row, and user reverses sorting, is it going start pointing to the last row?

[GuillaumeGomez]

Good question... I'm pretty sure you can have access to the data location directly, never looked how however. If you find out, please tell me. :3

[kornelski]

gtk_list_store_set_valuesv: assertion 'iter_is_valid (iter, list_store)' failed

Nope, I can't store iters.

[kornelski]

I think I've got a solution:

1. Use an unsorted ListStore for 1:1 relationship with Vec, and copy data back and forth using index<>row mapping
2. Prevent ListStore from being mixed up by wrapping it TreeModelSort https://stackoverflow.com/a/19063670/27009