Augments a UITableViewDelegate to let you detect which direction a UITableView has been scrolled.

ATScrollDirectionProxy.h

//  Created by Andrew Toulouse on 5/6/13.
//  Copyright (c) 2013 Andrew Toulouse. All rights reserved.

#import <Foundation/Foundation.h>

typedef NS_ENUM(NSUInteger, ATScrollDirection) {
    ATScrollDirectionUp,
    ATScrollDirectionDown
};

@interface ATScrollDirectionProxy : NSProxy <UITableViewDelegate>
@property (nonatomic, assign) ATScrollDirection direction;

- (id)initWithTableViewDelegate:(id<UITableViewDelegate>)tableViewDelegate;
@end

ATScrollDirectionProxy.m

//  Created by Andrew Toulouse on 5/6/13.
//  Copyright (c) 2013 Andrew Toulouse. All rights reserved.

#import "ATScrollDirectionProxy.h"

@interface ATScrollDirectionProxy ()
@property (nonatomic, strong) id<NSObject, UITableViewDelegate> tableViewDelegate;
@property (nonatomic, assign) BOOL trackOffset;
@property (nonatomic, assign) CGFloat lastScrollOffset;
@property (nonatomic, assign) CGFloat velocity;
@end

@implementation ATScrollDirectionProxy

- (id)initWithTableViewDelegate:(id<NSObject, UITableViewDelegate>)tableViewDelegate {
    if (self) {
        _tableViewDelegate = tableViewDelegate;
    }
    return self;
}

- (void)forwardInvocation:(NSInvocation *)invocation {
    [invocation invokeWithTarget:_tableViewDelegate];
}

- (NSMethodSignature *)methodSignatureForSelector:(SEL)sel {
        return [[_tableViewDelegate class] instanceMethodSignatureForSelector:sel];
}

- (BOOL)conformsToProtocol:(Protocol *)aProtocol {
    return [_tableViewDelegate conformsToProtocol:aProtocol];
}

- (BOOL)respondsToSelector:(SEL)aSelector {
    if (![[self class] instancesRespondToSelector:aSelector]) {
        return [[_tableViewDelegate class] instancesRespondToSelector:aSelector];
    }
    return YES;
}

#pragma mark - UIScrollViewDelegate methods

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {
    self.lastScrollOffset = scrollView.contentOffset.y;
    self.trackOffset = YES;

    if ([self.tableViewDelegate respondsToSelector:@selector(scrollViewWillBeginDragging:)]) {
        [self.tableViewDelegate scrollViewWillBeginDragging:scrollView];
    }
}

- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {
    self.velocity = velocity.y;
    self.trackOffset = NO;

    if ([self.tableViewDelegate respondsToSelector:@selector(scrollViewWillEndDragging:withVelocity:targetContentOffset:)]) {
        [self.tableViewDelegate scrollViewWillEndDragging:scrollView withVelocity:velocity targetContentOffset:targetContentOffset];
    }
}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
    if (self.trackOffset) {
        self.velocity = scrollView.contentOffset.y - self.lastScrollOffset;
        self.lastScrollOffset = scrollView.contentOffset.y;
    }

    if (self.velocity < 0) {
        self.direction = ATScrollDirectionUp;
    } else {
        self.direction = ATScrollDirectionDown;
    }

    if ([self.tableViewDelegate respondsToSelector:@selector(scrollViewDidScroll:)]) {
        [self.tableViewDelegate scrollViewDidScroll:scrollView];
    }
}

@end