A simple category for Sparrow that allows one to change the loopability of a SPDisplayObject.

SPDisplayObject+Loopability.h

//
//  SPDisplayObject+Loopability.h
//  Sparrow
//
//  Created by Shilo White on 11/9/11.
//  Copyright (c) 2011 Shilocity Productions. All rights reserved.
//

#import "SPDisplayObject.h"

@interface SPDisplayObject (Loopability)
@property (nonatomic, assign, readwrite) BOOL loopable;
@end

SPDisplayObject+Loopability.m

//
//  SPDisplayObject+Loopability.m
//  Sparrow
//
//  Created by Shilo White on 11/9/11.
//  Copyright (c) 2011 Shilocity Productions. All rights reserved.
//

#import "SPDisplayObject+Loopability.h"
#import "SPEventDispatcher.h"
#import "SPEnterFrameEvent.h"
#import "SPEvent_Internal.h"
#import <objc/runtime.h>

static char sLoopable;

@implementation SPDisplayObject (Loopability)
@dynamic loopable;

- (void)setLoopable:(BOOL)loopable {
    if ([self loopable] != loopable) {
        objc_setAssociatedObject(self, &sLoopable, [NSNumber numberWithBool:loopable], OBJC_ASSOCIATION_ASSIGN);
    }
}

- (BOOL)loopable {
    NSNumber *loopable = objc_getAssociatedObject(self, &sLoopable);
    return (loopable)?[loopable boolValue]:YES;
}
@end

@implementation SPEventDispatcher (Loopability)
- (void)dispatchEvent:(SPEvent*)event {
    NSMutableArray *listeners = [mEventListeners objectForKey:event.type];   
    if (!event.bubbles && !listeners) return;
    
    SPEventDispatcher *previousTarget = event.target;
    if (!previousTarget || event.currentTarget) event.target = self;
    
    if (event.type == SP_EVENT_TYPE_ENTER_FRAME) {
        SPDisplayObject *currentObject = (SPDisplayObject *)event.currentTarget;
        if (!currentObject) currentObject = (SPDisplayObject *)event.target;
	if (!currentObject.loopable) return;
	while (currentObject.parent) {
	    currentObject = (SPDisplayObject *)currentObject.parent;
	    if (!currentObject.loopable) return;
	}
    }
    
    [self retain];
    
    BOOL stopImmediatePropagation = NO;    
    if (listeners.count != 0)
    {    
        event.currentTarget = self;
        
        [listeners retain];
        for (NSInvocation *inv in listeners)
        {
            [inv setArgument:&event atIndex:2];
            [inv invoke];
            if (event.stopsImmediatePropagation) 
            {
                stopImmediatePropagation = YES;
                break;
            }
        }
        [listeners release];
    }
    
    if (!stopImmediatePropagation && event.bubbles && !event.stopsPropagation && 
        [self isKindOfClass:[SPDisplayObject class]])
    {
        event.currentTarget = nil;
        SPDisplayObject *target = (SPDisplayObject*)self;
        [target.parent dispatchEvent:event];
    }
    
    if (previousTarget) event.target = previousTarget;
    
    [self autorelease];
}
@end