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Implementing delete in an NSTableView


I’ve seen many ways to implement delete in an NSTableView. Many are good. Many hardcode references to something they shouldn’t, and those are bad.

Here’s an easy way:

Subclass NSTableView and override keyDown:


- (void)keyDown:(NSEvent *)theEvent {
    // handle delete
    unichar key = [[theEvent charactersIgnoringModifiers] characterAtIndex:0];
    if (key == NSDeleteCharacter && self.selectedRow != -1) {
        [NSApp sendAction:@selector(delete:) to:nil from:self];
    } else {
      [super keyDown:theEvent];
  }
}

This just lets the responder chain take care of it. Your window controller can easily handle it by just implementing delete:

- (IBAction)delete:(id)sender {
    if (self.tableView.selectedRowIndexes.count > 0) {
        [_tableView beginUpdates];
        [[self _patternSequence] removeChildrenAtIndexes:self.tableView.selectedRowIndexes];
        [_tableView endUpdates];
    }
}

EDIT: I probably should only call super keyDown if it wasn’t the delete key…otherwise we beep.



6 Responses to “Implementing delete in an NSTableView”

  1. Guillaume Laurent says:

    I might be missing something obvious, but the line

    [[self _patternSequence] removeChildrenAtIndexes:self.tableView.selectedRowIndexes];

    could do with a bit more explanations. Is _patternSequence the datasource of the NSTableView ?

  2. corbin says:

    Hi Guillaume —- that’s my model; it is backed by a core data obect. Maybe I’ll do a post on how to update your model and have a view based tableview animate along with it.

    corbin

  3. Guillaume Laurent says:

    Hi Corbin,

    Yes please, that would be a nice follow-up to this one :)

  4. aure says:

    Yeah we need a little more detail. In particular, I’m surprised I don’t see any “reloadData”. Maybe it’s because you’re using Cocoa Bindings ? or are the beginUpdates/endUpdates enough in all scenarios (with or without bindings ?)
    I’m glad you’re writing new Cocoa post. Those were missing (a lot). Thanks

  5. corbin says:

    Yeah, I am using CoreData…but I have it semi-using bindings.

  6. Seth says:

    Delete is easy, but what about copy? Can’t send the copy: action to nil because it’ll just get sent back to itself since the tableview is first responder.

(c) 2008-2012 Corbin Dunn

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