👀 Views: 57 💬 Answers: 1 📅 Created: 2025-06-12

macos appkit nsoutlineview Swift

I'm optimizing some code but I've been banging my head against this for hours. I'm experiencing issues with an `NSOutlineView` in my macOS 13.4 application. The outline view is supposed to dynamically update its rows when I add or remove items from the underlying data source, but the resizing behavior is inconsistent. Sometimes, after performing a series of additions and deletions, the outline view doesn't reflect the correct size until I manually resize the window or call `reloadData()`. I've tried implementing the `NSTableViewDelegate` methods to handle resizing but it hasn't resolved the scenario. Here’s a snippet of how I'm updating the data: ```swift class MyDataSource: NSObject, NSOutlineViewDataSource { var items: [MyItem] = [] func outlineView(_ outlineView: NSOutlineView, numberOfChildrenOfItem item: Any?) -> Int { return items.count } func outlineView(_ outlineView: NSOutlineView, child index: Int, ofItem item: Any?) -> Any? { return items[index] } func outlineView(_ outlineView: NSOutlineView, isItemExpandable item: Any) -> Bool { return false } func addItem(_ newItem: MyItem) { items.append(newItem) outlineView.reloadData() // This sometimes doesn't trigger a resize } func removeItem(at index: Int) { items.remove(at: index) outlineView.reloadData() // Same scenario here } } ``` I also attempted to call `outlineView.sizeToFit()` after updates, but it didn’t help either. The outline view is set to auto layout and the constraints seem fine. I’m not sure if this is a bug in macOS 13.4 or if I'm missing a crucial step in updating the view. Any suggestions on how to ensure the outline view resizes properly after data updates would be greatly appreciated. For context: I'm using Swift on Windows. Thanks for your help in advance!