AutoLayoutVFLViewController.m

#import "AutoLayoutVFLViewController.h"

@interface AutoLayoutVFLViewController ()
@property (strong, nonatomic) UILabel *label;
- (void)animateLabel;
@end

@implementation AutoLayoutVFLViewController

- (void)loadView
{
    CGRect applicationFrame = [[UIScreen mainScreen] applicationFrame];
    UIView *mainView = [[UIView alloc] initWithFrame:applicationFrame];
    mainView.backgroundColor = [UIColor whiteColor];
    self.view = mainView;
    
    self.label = [UILabel new];
    self.label.text = @"This is a Label";
    self.label.font = [UIFont systemFontOfSize:18];
    self.label.backgroundColor = [UIColor lightGrayColor];
    self.label.translatesAutoresizingMaskIntoConstraints = NO;
    [self.view addSubview:self.label];
    
    NSArray *constraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-offsetTop-[_label]"
                                                                   options:0
                                                                   metrics:@{@"offsetTop": @100}
                                                                     views:NSDictionaryOfVariableBindings(_label)];
     
    [self.view addConstraints:constraints];
     
    UIView *spacer1 = [UIView new];
    spacer1.translatesAutoresizingMaskIntoConstraints = NO;
    [self.view addSubview:spacer1];
     
    UIView *spacer2 = [UIView new];
    spacer2.translatesAutoresizingMaskIntoConstraints = NO;
    [self.view addSubview:spacer2];
     
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[spacer1][_label][spacer2(==spacer1)]|"
                                                                      options:0
                                                                      metrics:nil
                                                                        views:NSDictionaryOfVariableBindings(_label, spacer1, spacer2)]];
    
    
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self performSelector:@selector(animateLabel) withObject:nil afterDelay:2.0];
}


- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)animateLabel {
    [self.view.constraints enumerateObjectsUsingBlock:^(NSLayoutConstraint *constraint, NSUInteger idx, BOOL *stop) {
        if ((constraint.firstItem == self.label) && (constraint.firstAttribute == NSLayoutAttributeTop)) {
            constraint.constant = 200.0;
        }
     }];
    [UIView animateWithDuration:0.5 animations:^{
        [self.view layoutIfNeeded];
    }];
}

@end