Custom field editor for NSTextFieldCell in an NSTableView

Question

I have a custom NSTableView subclass filled with several custom NSTextFieldCell subclasses. I would like to be able to change the edited cell by using the arrow keys.

I am able to accomplish this by creating a custom field editor (by subclassing NSTextView) and returning it from the window delegate like so:

- (id) windowWillReturnFieldEditor:(NSWindow *) aWindow toObject:(id) anObject {
    if ([anObject isEqual:myCustomTable]) {
        if (!myCustomFieldEditor) {
            myCustomFieldEditor = [[MyNSTextViewSubclass alloc] init];
            [myCustomFieldEditor setTable:anObject];
        }
        return myCustomFieldEditor;
    }
    else {
        return nil;
    }
}

In MyNSTextViewSubclass, I override the moveUp:,moveDown:,moveLeft:,and moveRight: methods to implement my desired functionality, and that all works fine. The only problem is that the field editor no longer behaves like a text field cell editor. For example, when I hit the Enter key, it inserts a newline into the text field instead of ending the editing.

How do I create a custom field editor that responds exactly like the default one does for an NSTextFieldCell (except for those four functions that I will override)? Or is there a better way to change the functionality of moveUp:,moveDown:,moveLeft:,and moveRight:?

EDIT: It appears that the field editor sets the text field as its delegate when it is selected for editing. In that case, it might be helpful to just attach to the control:textView:doCommandBySelector: delegate method as described here, but when I implement that function in either my NSTextFieldCell subclass or my NSTableView subclass, it never gets called. Why not?

Answer 1

These should be overridden in keyDown:(NSEvent *)event method of your subclassed NSTextFieldCell object. You check the pressed key (one of the arrows) and otherwise call up to super.

Answer 2

I spent almost all day on this problem, but I finally figured it out. In order to be able to traverse my NSTableView subclass with the arrow keys, I had to add the following method to my NSTableView:

- (BOOL)textView:(NSTextView *)aTextView doCommandBySelector:(SEL)aSelector {
    if(aSelector == @selector(moveUp:)) {
        [self moveSelectionToPreviousRow];
        return YES;
    } else if(aSelector == @selector(moveDown:)) {
        [self moveSelectionToNextRow];
        return YES;
    } else if(aSelector == @selector(moveLeft:)) {
        [self moveSelectionToPreviousColumn];
        return YES;
    } else if(aSelector == @selector(moveRight:)) {
        [self moveSelectionToNextColumn];
        return YES;
    }
    return NO;
}

This is because the default field editor is an NSTextView (not an NSControl) so I needed to use the <NSTextViewDelegate> protocol. The view that is set as its delegate is the NSTableView, not the NSTextFieldCell. The moveSelectionTo... functions are custom functions defined in my NSTableView subclass that keep track of the currently edited cell and then move it around accordingly.