how to change uitableviewcell's frame height using contentOffset - ios

Question

I am trying to implement a table view in which as I scroll the height of the cell at top becomes bigger than rest of the cells.
I basically want the first cell to be of 200f always and rest to be 100f.
I am able to to do it when user is scrolling down but when user is scrolling to the top and is scrolling too fast, the frame is not reset properly.
relavant code:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
int row = scrollView.contentOffset.y / kSmallHeight;
_currentCellIndexPath = [NSIndexPath indexPathForRow:row inSection:0];
UITableViewCell *topCell = [self.tableView cellForRowAtIndexPath:_currentCellIndexPath];
NSIndexPath *path = [NSIndexPath indexPathForRow:_currentCellIndexPath.row + 1 inSection:_currentCellIndexPath .section];
UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:path];
[self.tableView insertSubview:cell aboveSubview:topCell];
[self adjustCellHeightForCell:cell withDefaultOffset:NO];
}
- (void)adjustCellHeightForCell:(UITableViewCell *)cell withDefaultOffset:(BOOL)defailtOffset
{
int row = self.tableView.contentOffset.y / kSmallHeight;
double fakeOriginy = (kBigHeight + kSmallHeight * (cell.tag-1));
double set = row * kSmallHeight;
CGRect frame = cell.frame;
double offset;
if(defailtOffset)
offset = kSmallHeight;
else {
offset = ((self.tableView.contentOffset.y - set ) * ((kBigHeight - kSmallHeight)/ kSmallHeight));
}
frame.origin.y = fakeOriginy - offset;
frame.size.height = kSmallHeight + offset;
cell.frame = frame;
}
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
int row = self.tableView.contentOffset.y / kSmallHeight;
_currentCellIndexPath = [NSIndexPath indexPathForRow:row inSection:0];
if(indexPath.row != 0 && indexPath.row < _currentCellIndexPath.row)
[self adjustCellHeightForCell:cell withDefaultOffset:YES];
}
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset
{
//This is the index of the "page" that we will be landing at
NSUInteger nearestIndex = (NSUInteger) ( (int)targetContentOffset->y % (int)kSmallHeight) >= kSmallHeight/2 ? targetContentOffset->y / kSmallHeight + 1 : targetContentOffset->y / kSmallHeight;
//Just to make sure we don't scroll past your conpo tent
nearestIndex = MAX( MIN( nearestIndex, self.store.coupons.count - 1 ), 0 );
//This is the actual x position in the scroll view
CGFloat yOffset = nearestIndex * kSmallHeight;
//I've found that scroll views will "stick" unless this is done
yOffset = yOffset==0?1:yOffset;
//Tell the scroll view to land on our page
*targetContentOffset = CGPointMake(targetContentOffset->x,yOffset);
}

Answer 1

Try This!
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
{
if(indexpath.row == 0)
{
//call your re-adjust height method here
[your_table setContentOffset:CGPointZero animated:YES];
[self adjustCellHeightForCell:cell withDefaultOffset:NO];
}
}

Answer 2

Iterating through the visible cells and resetting their frames at the end of viewDidScroll worked excluding the cell that has to be transformed i.e. first visible 100.0f cell on the screen.
[visibleCells enumerateObjectsUsingBlock:^(UITableViewCell *cell, NSUInteger idx, BOOL *stop) {
NSIndexPath *path = [self.tableView indexPathForCell:cell];
if(path.row > topCellPath.row + 1) {
// reset frames of small cells
}
else if(path.row <= topCellPath.row){
// reset frames of big cells
}
}];