iOS UITableView仅对第一个可见单元进行动画处理

Question

I want to implement an UITableView with some animation while the user is scrolling. Only the first visible (top most) cell has to be an different layout. Before the second cell reaches the top of UITableView I want to start the small animation. (changing background alpha and width of cells contentView etc.)

How could I handle this?

[UPDATE]

What I have tried so far:

• using UIScrollView delegate method scrollViewDidScroll:(UIScrollView *)scrollView together with UITableView´s visibleCells property using the first item of it to get the reference with no luck

Answer 1

This is what I have done:

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {

     if (!decelerate) {
          [self scrollingFinish];
     }
}

..

 - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
     [self scrollingFinish];
}

..

- (void)scrollingFinish {

    NSIndexPath *firstVisibleIndexPath = [[self.tableView indexPathsForVisibleRows] objectAtIndex:0];

    NSLog(@"first visible cell's section: %i, row: %i", (int) firstVisibleIndexPath.section, (int) firstVisibleIndexPath.row);


    APFCategoryCell * cell = (APFCategoryCell*) [self.tableView cellForRowAtIndexPath:firstVisibleIndexPath];

    [cell animateCell];

    [self.tableView scrollToRowAtIndexPath:firstVisibleIndexPath atScrollPosition:UITableViewScrollPositionTop animated:YES];

}

The problem appears, if the user is scrolling down because the animated cell is still visible and the next one gets animated. So two or more cells are animated. I could going on and implement an method in my custom cell like - (void) resetAnimatedCell but maybe there is an much more elegant way for doing this?