没有在scrollToItemAtIndexPath上调用Collectionview单元委托方法？

Question

我在控制器的viewDidLayoutSubviews部分中使用scrollToItemAtIndexPath ，以允许我将用户滚动到特定的单元格。

我的单元格作为cellForItemAtIndexPath一部分加载时，应该对其参数进行网络调用

问题是将打印语句放在cellForItemAtIndexPath似乎从未被调用过？ 造成冲突的原因是什么？如何解决冲突？ 代码如下：

- (void)viewDidLayoutSubviews {
    CDCChannelCollectionView *scrollView;

    if (self.view == [self mixMonitorView]) {
        scrollView = [[self mixMonitorView] scrollView];
        NSIndexPath *indexPath = [NSIndexPath indexPathForItem:0 inSection: self.selectedChanIndex];
        [scrollView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:YES];
    }
}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    CDCChannelStrip *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];

    if (self.view == self.mixMonitorView) {
        NSInteger chanInt = indexPath.section;
        NSNumber *chanNum = [NSNumber numberWithInteger:chanInt];
        NSNumber *chanNameNumber = [NSNumber numberWithInteger:chanInt + 1];
        NSString *chanName = [NSString stringWithFormat:@"CH %@", chanNameNumber];
        cell.channelNumber = chanInt;
        cell.channelName.text = chanName;
        [self getParameters:(chanNum)];
        [self.mixMonitorView setChannelsStripToType:(cell)];
        cell.clipsToBounds = YES;
        return cell;
    }
}

Answer 1

数据源方法将调用重新加载集合视图。

试试下面

[yourCollectionViewName reloadData];

Answer 2

scrollToItemAtIndexPath将不会调用数据源方法，除非它滚动到滚动前不可见的collectionViewCell 。 如果滚动到已经可见的单元格，则需要调用reloadData