What method should I call on my NSCell - objective-c

Question

I am writing a custom NSControl with custom NSCells. It is a control, so it has to respond to the mouse. I created an NSTrackingArea over my control, implemented -mouseEntered:, -mouseExited: and -mouseMoved:. (And I will have to implement -mouseUp/Down:, but I have no idea what to do in there, so for now I haven't overridden those methods yet.) In these methods I successfully determine on which cell the mouse currently is. Now I have two questions:
Is this a good approach for tracking the mouse? If not, what should I do instead?
What method should I call on my NSCell on a mouse click, when the mouse enters the cell, when the mouse leaves the cell etc? Apple's docs are not very clear about this.
So, basically: When should I call what method on my NSCell to let it respond to mouse events?
EDIT:
Rereading the docs, I think I should call NSCell's -trackMouse:inRect:ofView:untilMouseUp: and override -startTrackingAt:inView:, -continueTracking:at:inView: and -stopTracking:at:inView:mouseIsUp:. Again two questions: 1) the docs give the impression these are only called when the mouse is down. Is that correct? Then what should I do instead? 2) Where/when should I call NSCell's -trackMouse:inRect:ofView:untilMouseUp:?

Answer 1

I ended up implementing my own mouse tracking mechanism:
// MyControl.m:
- (void)mouseDown:(NSEvent *)theEvent {
int currentCellIndex = [self indexOfCellAtPoint:[self convertPoint:[theEvent locationInWindow] fromView:nil]];
if (currentCellIndex < [cells count]) {
MKListCell *cell = [cells objectAtIndex:currentCellIndex];
currentCell = cell;
[currentCell mouseDown:theEvent];
}
}
- (void)mouseUp:(NSEvent *)theEvent {
int currentCellIndex = [self indexOfCellAtPoint:[self convertPoint:[theEvent locationInWindow] fromView:nil]];
if (currentCellIndex < [cells count]) {
MKListCell *cell = [cells objectAtIndex:currentCellIndex];
[cell mouseUp:theEvent];
}
}
- (void)mouseEntered:(NSEvent *)theEvent {
int currentCellIndex = [self indexOfCellAtPoint:[self convertPoint:[theEvent locationInWindow] fromView:nil]];
if (currentCellIndex < [cells count]) {
MKListCell *cell = [cells objectAtIndex:currentCellIndex];
currentCell = cell;
[currentCell mouseEntered:theEvent];
}
}
- (void)mouseExited:(NSEvent *)theEvent {
int currentCellIndex = [self indexOfCellAtPoint:[self convertPoint:[theEvent locationInWindow] fromView:nil]];
if (currentCellIndex < [cells count]) {
MKListCell *cell = [cells objectAtIndex:currentCellIndex];
[cell mouseExited:theEvent];
currentCell = nil;
}
}
- (void)mouseMoved:(NSEvent *)theEvent {
int currentCellIndex = [self indexOfCellAtPoint:[self convertPoint:[theEvent locationInWindow] fromView:nil]];
MKListCell *cell;
if (currentCellIndex < [cells count]) {
cell = [cells objectAtIndex:currentCellIndex];
}
if (currentCell != cell) {
[currentCell mouseExited:theEvent];
[cell mouseEntered:theEvent];
currentCell = cell;
}
else {
[currentCell mouseMoved:theEvent];
}
}
- (void)mouseDragged:(NSEvent *)theEvent {
int currentCellIndex = [self indexOfCellAtPoint:[self convertPoint:[theEvent locationInWindow] fromView:nil]];
MKListCell *cell = nil;
if (currentCellIndex < [cells count]) {
cell = [cells objectAtIndex:currentCellIndex];
}
if (currentCell != cell) {
[currentCell mouseExited:theEvent];
[cell mouseEntered:theEvent];
currentCell = cell;
}
else {
[currentCell mouseMoved:theEvent];
}
}
- (int)indexOfCellAtPoint:(NSPoint)p {
int cellIndex = (self.bounds.size.height - p.y) / cellHeight;
return cellIndex;
}
And of course, in MyCell.h:
- (void)mouseDown:(NSEvent *)event;
- (void)mouseUp:(NSEvent *)event;
- (void)mouseMoved:(NSEvent *)event;
- (void)mouseEntered:(NSEvent *)event;
- (void)mouseExited:(NSEvent *)event;
With an empty implementation for those methods (so the compiler doesn't complain and I can leave the implementation of the mouse handling methods to subclasses).