UIScrolllView scroll limit position - ios

Question

I have an UITableView inside an UIScrollView and I want that the user will be able to scroll just when he touches the tableView (I have a map in the background and I want that the user will be able to integrate with the map when the tableView doesn't covers all of it.
I've tried to set scrollViewHeightConstraint.constant to scrollView.contentOffset.y on -(void)scrollViewDidScroll:(UIScrollView *)scrollView but it didn't work, part of the map is still not touchable. Can anyone give me an advice what should I do? Thanks!
Screenshot: Screenshot

Answer 1

OK. I think I understand what you're trying to do. Here is the solution I have come up with. Let me know if this works for you or not.
First off, you need to set the contentInset of the table view in your view controller (or if it's possible in the storyboard, set it there. Not sure if it is though?). It's a simple one-liner in viewDidLoad or viewWillAppear:, like so:
self.tableView.contentInset = UIEdgeInsetsMake(400.f, 0.f, 0.f, 0.f);
The 400.f is just saying start the table view's content 400 points from the top. You can set it to whatever number you'd like or, if you know you want it 200 points from the bottom, do something like this:
self.tableView.contentInset = UIEdgeInsetsMake(self.view.bounds.size.height - 200.f, 0.f, 0.f, 0.f);
With your content situated OK, now you need to create a subclass of UITableView to use as your table view's class. This class should override one method: hitTest:withEvent:. You can set which class you're using for your table view in your storyboard (click on the table view, then go to the Identity Inspector), or you can just change it in your view controller if you're not using storyboards.
In the method you're overriding, you're checking to see if where the user has touched the screen is above the contentInset or not (which works for your design). For a more complex design, you'd need some more robust checking.
This should allow the MKMapView to intercept the scroll events from the table view (which is returning nil and disabling scrolling).
Here is the UITableView subclass (you can name it whatever you want):
EmbeddedTableView.h
#import <UIKit/UIKit.h>
#interface EmbeddedTableView : UITableView
#end
EmbeddedTableView.m
#import "EmbeddedTableView.h"
#implementation EmbeddedTableView
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
if (point.y < 0.f) {
self.scrollEnabled = NO;
} else {
self.scrollEnabled = YES;
return [super hitTest:point withEvent:event];
}
return nil;
}
#end