dim everything but selected row ios

Question

How could I easily dim the complementary set of rows, when one gets selected.

Right now I have the code to select a cell so I can call a method on it, but I would like to set opacity of all the other rows.

-(void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    SummaryCell * selectedCell = [tableView cellForRowAtIndexPath:indexPath];
    [selectedCell manageContent];
}

Edit: I dont want to iterate through all the other cells (because there will be a lot of them) - wouldn't it be easier to add an UIView above all other cell (this would also prevent user interaction) and place the selected cell above that view (something like increasing z-index in HTML).

Answer 1

It depends what you mean by "dim" the other rows. The process to iterate over all visible rows and to set a property on all the rows other than the one selected is as follows:-

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    for (UITableViewCell *otherCell in self.tableView.visibleCells) {
        NSIndexPath *otherIndexPath = [self.tableView indexPathForCell:otherCell];
        if (![indexPath isEqual:otherIndexPath]) { // exclude the selected cell
            // Do whatever you want with otherCell here
        }
    }
}

Where my comment is, you can set whatever properties you like on otherCell. For example, otherCell.alpha which is the alpha (transparency) of that cell.

Answer 2

You can iterate all the visible cells, configure them to be dimmed, then on the datasource cellForIndex method check if there's a selected cell, if there is, check if it is at the asked index, if so configure the cell as selected, if not as dimmed.