无法监听到滚动到第几 section 值

[zeqinjie]

业务中需要监听滚动时候的section 从而设置头部导航栏 title 需求, 使用ZL 不行，但使用系统的layout可以监听到

参考 https://www.cnblogs.com/qqcc1388/p/5891665.html 方法 ~

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
NSInteger currentIndex = 0;
CGRect visibleRect = (CGRect){.origin = self.collectionViewLabel.contentOffset, .size = self.collectionViewLabel.bounds.size};
CGPoint visiblePoint = CGPointMake(CGRectGetMidX(visibleRect), CGRectGetMidY(visibleRect));
NSIndexPath *visibleIndexPath = [self.collectionViewLabel indexPathForItemAtPoint:visiblePoint];

if (currentIndex == visibleIndexPath.section || visibleIndexPath == nil) {
    return;
}
currentIndex = visibleIndexPath.section;
NSLog(@"currentIndex: %ld",currentIndex);

}

> 这样的方式也不行

• (void)scrollViewDidScroll:(UIScrollView )scrollView { NSInteger currentIndex = 0; CGRect visibleRect = (CGRect){.origin = self.collectionViewLabel.contentOffset, .size = self.collectionViewLabel.bounds.size}; CGPoint visiblePoint = CGPointMake(CGRectGetMinX(visibleRect), CGRectGetMinY(visibleRect)); UICollectionViewLayoutAttributes attribute = [[self.collectionViewLabel.collectionViewLayout layoutAttributesForElementsInRect:visibleRect] firstObject]; if (attribute == nil) { return; } currentIndex = attribute.indexPath.section; NSLog(@"currentIndex: %ld",currentIndex); }

[czl0325]

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
    NSInteger currentIndex = 0;
    ZLCollectionViewVerticalLayout* layout = (ZLCollectionViewVerticalLayout*)self.collectionViewLabel.collectionViewLayout;
    NSMutableArray* arr = [NSMutableArray new];
    [arr addObject:@"0"];
    [arr addObjectsFromArray:layout.collectionHeightsArray];
    for (NSInteger i = 0; i < arr.count-1; i++) {
        CGFloat height1 = [arr[i] floatValue];
        CGFloat height2 = [arr[i+1] floatValue];
        if (scrollView.contentOffset.y >= height1 && scrollView.contentOffset.y < height2) {
            currentIndex = i;
            break;
        }
    }
    NSLog(@"当前所在section=%zd", currentIndex);
}