ios8.0 gesture conflict crash

[heemoe]

- (void)commonInit {

    if (self.parentViewController.parentViewController && [self.parentViewController.parentViewController isKindOfClass:[UINavigationController class]]) {
        UINavigationController *navi = (UINavigationController *)self.parentViewController.parentViewController;

        if (navi.interactivePopGestureRecognizer) {
            navi.interactivePopGestureRecognizer.delegate = self;
            [self.collectionView.panGestureRecognizer requireGestureRecognizerToFail:navi.interactivePopGestureRecognizer];
        }
    }
//    // 发布通知 默认为0
//    [self addCurrentShowIndexNotificationWithIndex:0];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(receiveMemoryWarningHander:) name:UIApplicationDidReceiveMemoryWarningNotification object:nil];
//    [self.collectionView addObserver:self forKeyPath:kContentOffsetOffKey options:NSKeyValueObservingOptionNew context:nil];
}

crash when swipe back to a view then do swipe gesture on this view. removed the above code is work. but i don't know why ...

[jasnig]

ok, I am going to check this problem when I am free of time. Thanks for your reminder.