scrollToIndexPath方法无效 about hjcarouseldemo HOT 3 OPEN

    UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init] ;
    layout.itemSize = CGSizeMake(
                         APP_WIDTH - kFlexOfSide ,
                         APP_HEIGHT - APP_NAVIGATIONBAR_HEIGHT - APP_STATUSBAR_HEIGHT - APP_SAFEAREA_TABBAR_FLEX - kFlexOfSide
                                 ) ;
    [self.collectionView registerNib:[UINib nibWithNibName:@"DetailCollectionCell" bundle:nil] forCellWithReuseIdentifier:@"DetailCollectionCell"] ;
    self.collectionView.collectionViewLayout = layout ;
    self.collectionView.dataSource = self ;
    self.collectionView.delegate = self ;
    self.collectionView.backgroundColor = [UIColor xt_bg] ;
    [self.collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForRow:self.sendIndex inSection:0]
                                atScrollPosition:UICollectionViewScrollPositionCenteredVertically
                                        animated:NO] ;
    @weakify(self)
    [[RACObserve(self.collectionView, contentOffset)
      throttle:.8]
     subscribeNext:^(id  _Nullable x) {
         @strongify(self)
         PwdItem *currentItem = self.dataSource[self.currentIndex] ;
         self.title = currentItem.name ;
     }] ;
    
    dispatch_async(dispatch_get_main_queue(), ^{
        HJCarouselViewLayout *layout = [[HJCarouselViewLayout alloc] initWithAnim:HJCarouselAnimCarousel1] ;
        layout.visibleCount = 3 ;
        layout.itemSize = CGSizeMake(
                                     APP_WIDTH - kFlexOfSide ,
                                     APP_HEIGHT - APP_NAVIGATIONBAR_HEIGHT - APP_STATUSBAR_HEIGHT - APP_SAFEAREA_TABBAR_FLEX - kFlexOfSide
                                     ) ;
        self.collectionView.collectionViewLayout = layout ;
        
        [self.collectionView selectItemAtIndexPath:[self curIndexPath]
                                          animated:NO                                    scrollPosition:UICollectionViewScrollPositionCenteredVertically] ;
    }) ;