Switch in UIAlert Controller programmatically

Question

I am creating an registration dialog in swift with 3 text field and one Switch and I successfully add three text field two the Alert. The following code shows the same.

Answer 1

This answer is for Objective C. It doesn't use text fields but it does add a UISwitch to a UIAlertController as asked in the main question. I didn't find anything on SO that does exactly this so I'm posting this answer here, rather than posting another question that will get dinged as a duplicate.

This solution is used to enable users to sort a UITableView menu (of a list of projects...)

Thanks to the answer by @technerd, I also made the UISwitch change the text of a UILabel that is also on the same UIAlertController view. It uses KVC (Key-Value Coding) in the layer to pass the UILabel id to the target action when the UISwitch value is changed. (See the setOrderLabelText method in the code)

I was also trying to get around the trick of adding newlines ("\n\n\n\n") to the title or message to artificially move things around, by using constraints.

I used a horizontal UIStackView to hold the UISwitch and it's corresponding UILabel, and then used constraints to set the top anchor of the UIStack and a height constraint on the UIAlertController view to make it big enough to contain the UIStackView and the UIAlertController title.

I don't think it is possible to get the height of the title of the UIAlertController or the height of the action buttons. So I came up with values that worked well on an iPhone X and an iPad 2. As in other SO answers, I will likely come up with a home grown (or find one on GitHub) solution to make this more robust. But since I got this far and got so much from other awesome SO answers, I wanted to give back a bit and share my results.

Here's a screenshot:

And here's the code:

// using KVC, set the label text based on the label tag and toggle the tag
- (void)setOrderLabelText:(UISwitch *)orderSwitch {
    UILabel *label = (UILabel *)[orderSwitch.layer valueForKey:@"label"];

    label.text = label.tag ? @"Ascending" : @"Descending";

    label.tag = label.tag ? 0 : 1;

}

// sort the data based on the user's selections
- (IBAction)sort:(UIButton *)sortButton {    
    UILabel *label = [[UILabel alloc] init];
    label.text = @"Ascending";
    label.textColor = UIColor.grayColor;
    label.tag = 0;
    [label sizeToFit];

    UISwitch *orderSwitch = [[UISwitch alloc] init];
    orderSwitch.on = YES;
    [orderSwitch setOn:YES animated:YES];

    // allow the switch to change the text in the label using KVC (key-value coding)
    [orderSwitch addTarget:self action:@selector(setOrderLabelText:) forControlEvents:UIControlEventValueChanged];
    [orderSwitch.layer setValue:label forKey:@"label"];

    UIStackView *stackView = [[UIStackView alloc] init];
    stackView.axis = UILayoutConstraintAxisHorizontal;
    stackView.spacing = 8;

    [stackView addArrangedSubview:orderSwitch];
    [stackView addArrangedSubview:label];

    UIAlertController *alert = [UIAlertController
                                alertControllerWithTitle: @"Sort Projects By"
                                message: nil
                                preferredStyle:UIAlertControllerStyleAlert];

    UIAlertAction *createdButton = [UIAlertAction
                                  actionWithTitle:@"Created"
                                  style:UIAlertActionStyleDestructive
                                  handler:^(UIAlertAction * action) {
                                      [self sortBy:@"created" ascending:orderSwitch.isOn];
                                  }];
    UIAlertAction *titleButton = [UIAlertAction
                                  actionWithTitle:@"Title"
                                  style:UIAlertActionStyleDestructive
                                  handler:^(UIAlertAction * action) {
                                      [self sortBy:@"title" ascending:orderSwitch.isOn];
                                  }];
    UIAlertAction *subtitleButton = [UIAlertAction
                                  actionWithTitle:@"Subtitle"
                                  style:UIAlertActionStyleDestructive
                                  handler:^(UIAlertAction * action) {
                                      [self sortBy:@"subtitle" ascending:orderSwitch.isOn];
                                  }];
    UIAlertAction *cancelButton = [UIAlertAction
                                   actionWithTitle:@"Cancel"
                                   style:UIAlertActionStyleCancel
                                   handler:^(UIAlertAction * action) {
                                   }];

    // add action buttons to the alert
    [alert addAction:createdButton];
    [alert addAction:titleButton];
    [alert addAction:subtitleButton];
    [alert addAction:cancelButton];

    [alert.view addSubview:stackView];

    // center the stack in the alert
    [stackView.centerXAnchor constraintEqualToAnchor:alert.view.centerXAnchor].active = YES;

    // turn off the autoresizing mask or things get weird
    stackView.translatesAutoresizingMaskIntoConstraints = NO;

    // use a topAnchor constraint to place the stackview, just below the title
    // TODO:  figure out how to get the height of the alert title (use 64 for now)
    [stackView.topAnchor constraintEqualToAnchor:alert.view.topAnchor constant:64].active = YES;

    // layout now to set the view bounds so far - NOTE this does not include the action buttons
    [alert.view layoutIfNeeded];

    // use a height constraint to make the alert view big enough to hold my stack view
    // NOTE:  strange, but this must include the header view AND all the action buttons
    // TODO:  figure out how to get the height of the action buttons (use 52 for each action button for now)
    CGFloat height = alert.view.bounds.size.height + alert.actions.count * 52 + stackView.bounds.size.height;
    [alert.view.heightAnchor constraintEqualToConstant:height].active = YES;

    [self presentViewController:alert animated:YES completion:nil];
}