The number of new features introduced with iOS 8 is enormous. On of them is Adaptive Layout that makes implementing user interfaces much easier. One implementation can handle multiple devices, screen rations and orientations thanks to Size Classes. That’s a nice feature, but there is more about new UI that makes it great from developer point of view.

All of the iOS applications that I’ve been working on, implements table views to display some data. Sometimes it’s just a simple user interface, but in many cases, the UITableView is used to present sophisticated UI with text, images etc. With iOS 8, Apple introduces Self-Sizing Table Cells. That means, you don’t have to implement

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath

method anymore to have customized cell heights. Now it’s handled automatically by Auto Layout constraints! You can encapsulated the sizing logic in cells, which makes them more reusable and helps implementing clear UI logic.

As an example, if you have a table view cell with a text view inside, you can add NSLayoutConstraint inside UITableViewCell initialization method and you are good to go. No more coding is required to make customized, dynamic cells height. The cell’s height will adjust automatically to contained UITextView height:

@interface MyTableViewCell ()

@property (weak, nonatomic) IBOutlet UITextView *textView;

@end

@implementation MyTableViewCell

- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier 
{
    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
    if (self) {
        [self.contentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-textView-|"
                                                                                 options:0
                                                                                 metrics:nil
                                                                                   views:NSDictionaryOfVariableBindings(self.textView)]];
        [self.contentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-textView-|"
                                                                                 options:0
                                                                                 metrics:nil
                                                                                   views:NSDictionaryOfVariableBindings(self.textView)]];
    }
    return self;
}

So far that’s one of the best changes that I will surely use in my projects. As I haven’t seen all the goods that are coming, I believe that there are more improvements like this one. Great job Apple!

Update:

It looks like there is one more step required in order to make this feature working. It’s nothing complicated, but you have to configure your UITableView:

tableView.estimatedRowHeight = 44.0
tableView.rowHeight = UITableViewAutomaticDimension

or it won’t work like expected. Changing value of estimatedRowHeight doesn’t have huge impact on the layout, but it’s mandatory – otherwise it’s just not working.

Self-sizing cells can be implemented programmatically, like explained above, as well as using Interface Builder. It works in Objective C and Swift. It’s really all about proper constraints added to cell’s contentView subviews.