Mouse tracking with modifier keys in table view cell

Question

I have a NSTextFieldCell in a column of a cell-based NSTableView. This cell should handle clicks. This works fine when no modifier keys are pressed. If I hold the shift or command keys, the table view swallows the mouseDown event in an attempt to handle row selection.

Is there a way to completely disable row selection in NSTableView?

Is there a way to have NSTableView pass through all events?

My cell subclass is derived from the LinkTextFieldCell in the TableViewLinks sample code. It implements:

- (BOOL)trackMouse:(NSEvent *)theEvent inRect:(NSRect)cellFrame ofView:(NSView *)controlView untilMouseUp:(BOOL)flag

Since I don't want row selection, my table view delegate implements:

- (BOOL)tableView:(NSTableView *)tableView shouldSelectRow:(NSInteger)rowIndex
{
    return NO;
}

- (BOOL)tableView:(NSTableView *)tableView shouldTrackCell:(NSCell *)cell forTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row
{
    return YES;
}

My delegate methods are called from -[NSTableView mouseDown:]. The mouse tracking code is called when no modifier keys are pressed.

Is there a better way to fix this than subclassing NSTableView to override -[NSTableView mouseDown:]?

Can you have the table refusesFirstResponder? That's all I can think of, but I'm not sure it wouldn't break something else. — stevesliva
For some reason, I already had acceptsFirstResponder return NO. Makes no difference. — Pierre Bernard

Pierre Bernard Pierre Bernard · Accepted Answer · 2014-05-02T19:38:40

I have implemented a solution where I override mouseDown:. I don't really like it. But it works. Still hoping for better ideas.

- (void)mouseDown:(NSEvent *)theEvent
{
    if (! [self handleMouseDown:theEvent]) {
        [super mouseDown:theEvent];
    }
}

- (BOOL)handleMouseDown:(NSEvent *)theEvent
{
    NSInteger                   clickCount                  = [theEvent clickCount];

    if (clickCount != 1) {
        return NO;
    }

    NSPoint                     locationInWindow            = [theEvent locationInWindow];
    NSPoint                     locationInView              = [self convertPoint:locationInWindow fromView:nil];
    NSInteger                   clickedRow                  = [self rowAtPoint:locationInView];
    NSInteger                   clickedColumn               = [self columnAtPoint:locationInView];

    if ((clickedRow < 0) || (clickedColumn < 0)) {
        return NO;
    }

    if ((clickedRow >= [self numberOfRows]) || (clickedColumn >= [self numberOfColumns])) {
        return NO;
    }

    NSArray                     *tableColumns               = [self tableColumns];

    NSTableColumn               *tableColumn                = [tableColumns objectAtIndex:clickedColumn];
    NSCell                      *cell                       = [tableColumn dataCellForRow:clickedRow];

    id <NSTableViewDelegate>    delegate                    = [self delegate];
    BOOL                        shouldTrackCell             = NO;

    if ([delegate respondsToSelector:@selector(tableView:shouldTrackCell:forTableColumn:row:)]) {
        shouldTrackCell = [delegate tableView:self shouldTrackCell:cell forTableColumn:tableColumn row:clickedRow];
    }

    if (! shouldTrackCell) {
        return NO;
    }

    BOOL                        prefersTrackingUntilMouseUp = [[cell class] prefersTrackingUntilMouseUp];
    NSRect                      cellFrame                   = [self frameOfCellAtColumn:clickedColumn row:clickedRow];

    return [cell trackMouse:theEvent inRect:cellFrame ofView:self untilMouseUp:prefersTrackingUntilMouseUp];
}

Mouse tracking with modifier keys in table view cell

1 Answers