mouseEntered and mouseExited not called in NSImageView SubClass

Question

I created a subclass of NSImageView to capture mouseEntered and mouseExited events. But only mouseUp and mouseDown events are getting called. How to capture the mouseEntered and mouseExited events in NSImageView subclass?

Answer 1

If You want to use mouseEntered: and mouseExited: You need to use NSTrackingArea. Here is reference NSTrackingArea Class Reference.

Example:

//Add this to Your imageView subclass

-(void)mouseEntered:(NSEvent *)theEvent {
    NSLog(@"Mouse entered");
}

-(void)mouseExited:(NSEvent *)theEvent
{
    NSLog(@"Mouse exited");
}

-(void)updateTrackingAreas
{ 
    [super updateTrackingAreas];
    if(trackingArea != nil) {
        [self removeTrackingArea:trackingArea];
        [trackingArea release];
    }

    int opts = (NSTrackingMouseEnteredAndExited | NSTrackingActiveAlways);
    trackingArea = [ [NSTrackingArea alloc] initWithRect:[self bounds]
                                                 options:opts
                                                   owner:self
                                                userInfo:nil];
    [self addTrackingArea:trackingArea];
}