Repository files navigation

UIView+FDCollapsibleConstraints builds tocollapse a view and its relevant layout constraints, simulating a"Flow Layout" mode.

This demo collapses theforkingdog image view and its bottom margin constraint.

This demo collapses diffent components in cell, according to its data entity, each margin handles right as well.

First, tell which constraints will be collapsed when the view collapses. We provide aIBOutletCollection to make it easier in Interface Builder:

@property (nonatomic, copy) IBOutletCollection(NSLayoutConstraint) NSArray *fd_collapsibleConstraints;

You can assgin it by codes, but it's better to"connect lines" in Interface Builder:

Selected constraints will collapse when:

view.fd_collapsed = YES;

And expand back when:

view.fd_collapsed = NO;

Not every view needs to add a width or height constraint, views likeUILabel,UIImageView have theirIntrinsic content size when they have content in it. For these views, we provide aAuto collapse property, when its content is gone, selected constraints will collapse automatically.
You can enable auto collapse by:

label.fd_autoCollapse = YES;imageView.fd_autoCollapse = YES;

And it will work as you expect:

label.text = nil/*or @""*/; (auto => label.fd_collapsed = YES)label.text = @"forkingdog"; (auto => label.fd_collapsed = NO)imageView.image = nil; (auto => imageView.fd_collapsed = YES)imageView.image = [UIImage imageNamed:@"forkingdog"]; (auto => imageView.fd_collapsed = NO)

We've also offered a Interface Builder friendly way to enableauto collapse:

@property (nonatomic, assign, getter=fd_autoCollapse) IBInspectable BOOL autoCollapse;

Here's what you may find inAttribute Inspector

It's behavior is same as settingfd_autoCollapse property in code.

Cocoapods:

pod search UIView+FDCollapsibleConstraints

MIT