Question

In AcaniUsers, I’ve created a grid of ThumbView : UIView instances inside of a UITableView. All thumbViews have a width of kThumbSize. How do I detect if touches ended inside the same view in which they began?

Answer 1

The following works, but I’m not sure if it’s the best way to go about it. I think so though.

Since all thumbViews have a width of kThumbSize, just check in touchesEnded that the x-coordinate of the locationInView of the UITouch instance (assuming self.multipleTouchEnabled = NO) is less than or equal to kThumbSize. This means the touches ended inside the thumbView. No need to check the y-coordinate because if the touches move vertically, the tableView, which contains the thumbViews, scrolls and the touches are cancelled.

Do the following in ThumbView : UIView (whose instances are subviews of a UITableView):

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    NSLog(@"touchesEnded %@", touches);
    CGPoint touchPoint = [[touches anyObject] /* only one */ locationInView:self];
    if (touchPoint.x >= 0.0f && touchPoint.x <= kThumbSize) {
        [(ThumbsTableViewCell *)self.superview.superview thumbTouched:self];
    }
}

To only register touches on one thumbView at a time, you also probably want to set self.exclusiveTouch = YES; in the init instance method of ThumbView.