App Crashing with NSMutableArray

Question

I'm pretty new to iOS, and I have no idea how to find a decent stacktrace like JAVA, so all I can find on why it's crashing is, "sigabrt".

I know it has something to do with this code I just added.

-(void) clearGame {
    for (CCSprite *sprite in placedSprites) {
        if(sprite == nil) continue;
        [self removeChild:sprite cleanup:NO];
        [placedSprites removeObject:sprite];
    }
    placedSprites = [[NSMutableArray alloc] initWithCapacity:1000];
}

Where the class I'm adding this to is a Layer in cocos2d. In it's init method, I have

placedSprites = [[NSMutableArray alloc] initWithCapacity:1000];

I don't know what could be wrong, so any help is appreciated.

Thank you!

When you see just "SIGABRT" and no stack trace nor the details of the exception, add an "Exception breakpoint" in XCode. Details at http://stackoverflow.com/questions/4961770/run-stop-on-objective-c-exception-in-xcode-4 — kuba, Feb 28 '12 at 21:40

score 7 · Accepted Answer · edited May 23 '17 at 12:00

You cannot remove an object from a NSMutableArray while fast-enumerating (see documentation).

You could add the objects (which should be removed) to a separate NSMutableArray and remove the objects from this array from your 'main' array:

NSMutableArray *discardedItems = [NSMutableArray array];
SomeObjectClass *item;

for (item in originalArrayOfItems) {
    if ([item shouldBeDiscarded])
        [discardedItems addObject:item];
}

[originalArrayOfItems removeObjectsInArray:discardedItems];

Also see Removing object from NSMutableArray and Best way to remove from NSMutableArray while iterating?.

App Crashing with NSMutableArray

1 Answers1