Hide cells in a UITableView with static cells - and no autolayout crash

Question

I have a table view form created using Static Cells in IB/Storyboard. However, I need to hide some of the cells at runtime depending on certain conditions.

I have fo

Answer 1

I found the best way to do this is to simply handle the numberOfRowsInSection, cellForRowAtIndexPath and heightForRowAtIndexPath to selectively drop certain rows. Here's a 'hardcoded' example for my scenario, you could do something a little smarter to intelligently remove certain cells rather than hard code it like this, but this was easiest for my simple scenario.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [super tableView:tableView cellForRowAtIndexPath:indexPath];
    if (indexPath.section == 0 && hideStuff) {
        cell = self.cellIWantToShow;
    }
    return cell;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    CGFloat height = [super tableView:tableView heightForRowAtIndexPath:indexPath];
    if (indexPath.section == 0 && hideStuff) {
        height = [super tableView:tableView heightForRowAtIndexPath:[NSIndexPath indexPathForRow:2 inSection:0]];
    }
    return height;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    NSInteger count = [super tableView:tableView numberOfRowsInSection:section];

    if (section == 0 && hideStuff) {
        count -= hiddenCells.count;
    }

    return count;
}

Answer 2

I managed to avoid exceptions from Auto Layout by first removing the constraints on the cell's contentView programmatically in viewDidLoad, and then setting that cell's height to 0 in heightForRowAtIndexPath.

Answer 3

I have found a way that allows you even row animations and is working on iOS 8.3. All you need is to implement the tableView:numberOfRowsInSection: data source method and then add/delete row by UITableView methods insertRowsAtIndexPaths:withRowAnimation: and deleteRowsAtIndexPaths:withRowAnimation:.

Here is example of hiding exact row based on UISwitch state:

- (IBAction)alowNotif:(id)sender {
    UISwitch *sw = (UISwitch*)sender;
    NSIndexPath *index = [NSIndexPath indexPathForRow:5 inSection:0];
    if ([sw isOn]) {
        [self.tableView insertRowsAtIndexPaths:@[index] withRowAnimation:UITableViewRowAnimationAutomatic];
    }
    else {
        [self.tableView deleteRowsAtIndexPaths:@[index] withRowAnimation:UITableViewRowAnimationAutomatic];
    }
}

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    if (![notifications isOn]) {
        return 5;
    }
    return 6;
}

As was mentioned above by @algal, numberOfRowInSection: is still UITableViewDataSource method, so one does not simply know how long its gonna work.

Answer 4

Implemented this too, for a tableview in a StoryBoard. My cells are embedded in sections with a header, represented by that blue cube in xcode6 IB. Indeed if you implement heightForHeaderInSection, heightForFooterInSection and titleForHeaderInSection,titleForFooterInSection you can access the headers when the table is displayed, and return 0.0 and nil respectively, and return 0 for numberOfRowsInSection.

Basically it all works fine, except that for every cell hidden a ca. 10 pixel high vertical space remains for every cell (section) you hide. Any idea what that could be?

Answer 5

The simplest way is to change height of sections and rows. It works for me.

- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
    if (section == 3) {
        return 0;
    } else {
        return [super tableView:tableView heightForHeaderInSection:section];
    }
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = [super tableView:tableView cellForRowAtIndexPath:indexPath];
    if (indexPath.section == 3) {
        cell.hidden = YES;
        return 0;
    } else {
        cell.hidden = NO;
        return [super tableView:tableView heightForRowAtIndexPath:indexPath];
    }
}

Answer 6

The kosher way to do this is to use dynamic cells, setting the row height to 0 is a hack. Static cells are very convenient but limited in functionality.