Create iOS constraints in code

ConstraintsInCode.m

...
UIView* contentView = [[UIView alloc] init];
contentView.translatesAutoresizingMaskIntoConstraints = NO;
contentView.backgroundColor = [UIColor grayColor];
contentView.layer.cornerRadius = 12.0;

UILabel* statusLabel = [[UILabel alloc] init];
statusLabel.translatesAutoresizingMaskIntoConstraints = NO;
statusLabel.backgroundColor = [UIColor clearColor];
statusLabel.textColor = [UIColor whiteColor];
statusLabel.font = [UIFont boldSystemFontOfSize:12.0];
statusLabel.numberOfLines = 0;  // cover all lines
statusLabel.text = text;

[contentView addSubview:statusLabel];

NSDictionary* views = NSDictionaryOfVariableBindings(contentView, statusLabel);

[contentView addConstraints:
 [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-(16)-[statusLabel]-(10)-|"
                                         options:NSLayoutFormatAlignAllCenterX
                                         metrics:nil
                                           views:views]];

[contentView addConstraints:
 [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-(36)-[statusLabel]-(36)-|"
                                         options:0
                                         metrics:nil
                                           views:views]];
  ...