Why not just use Auto Layout in pure code?

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.