ALChains

Auto Layout chains - chain based auto-layout constraint builder

Why?

This is ugly:

NSLayoutConstraint *constraint = [NSLayoutConstraint constraintWithItem:view
                                      attribute:NSLayoutAttributeWidth
                                      relatedBy:NSLayoutRelationEqual
                                         toItem:otherView
                                      attribute:NSLayoutAttributeWidth
                                     multiplier:1.0
                                       constant:0];
[view addConstraint:constraint];

Writing the same thing with ALChains:

ALChains(view)
  .widthEqualToView(otherView)
  .apply();

Examples

View with fixed dimensions (300 x 180)

ALChains(view)
  .widthEqualTo(300)
  .heightEqualTo(180)
  .apply();

View completely fills superview

ALChains(view)
  .fill()
  .apply();

View with fixed dimensions centered in superview, but offset in Y direction by 20

ALChains(view)
  .widthEqualTo(300)
  .heightEqualTo(180)
  .centerX(0)
  .centerY(20)
  .apply();

View with same height as another view, positioned to its right with a margin of 10

ALChains(view)
  .widthEqualTo(100)
  .heightEqualToView(otherView)
  .adjacentRight(otherView, 10)
  .apply();

How it works

Nothing more than a nice way of building and adding layout constraints to a view. It's pretty simple, might not cover all use cases, but i've found it pretty useful in my own projects.

Compatibility

Compatible with both iOS (UIView) and Mac (NSView) views.