Apple's options for Auto Layout in code aren't the best. Check out some of the fantastic third party APIs available.
I'm the developer of UIView+AutoLayout, which is designed to provide the API that Apple should have in the first place (it's inspired heavily by the IB options): https://github.com/smileyborg/UIView-AutoLayout
buttonView = [[UIButton alloc] init];
buttonView.translatesAutoresizingMaskIntoConstraints = NO;
[self.view addSubview:buttonView];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:buttonView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeBottom multiplier:1.0f constant:0.0f]];
... etc
It's certainly better than the stress you'll have with UIView+Positioning or IB.