VBAutolayout

There are developers (like me) who prefer to create UI programmatically due to numerous reasons. I use storyboards for segues and user scene-path. But UIViewControllers are left empty. And I do not use xibs.

When you create adaptive UI programmatically the view (or viewcontroller) code becomes unreadable because of big autolayout creation calls.

VBAutolayout is a library which makes programmatic autolayout creation comfortable, readable and code-minimized.

Format

Views layout is described in a dictionary with special VBAutolayout format. Constraints are created only for VBAutolayoutAttribute-s contained in layout dictionary. Attribute is ignored if no VBAutolayoutConstant value was given.

Layout dictionary format:

    @{VBAutolayoutAttribute: <1>,
      VBAutolayoutAttribute: <2>,
      VBAutolayoutAttribute: <3>
    }
        
    <1> =  <const>
    
    <2> =  @{VBAutolayoutItem: <item>,
             VBAutolayoutConstant: <const>}
    
    <3> =  @[<1>, <2>, ...]

<item> is a view2 in constraint. If no <item> specified, then superview is used and constraint is interpreted as a constraint to view container.

<const> is a string with the same format as could be used for Visual Format Constraints Creation

    <const> = <relation><constant>@<priority>, ex. 10, ==10, >=10, <=10, 10@999, >=10@999, etc.
    <relation> =    1) <, <= for <=
                    2) >, >= for >=
                    3) =, == for ==

Several constraints can be combined for one attribute using variant <3>.

Examples,

• distance greater or equal then 10 from item top to someView bottom with 999 priority

    VBAutolayoutAttributeTop: @{VBAutolayoutItem: __someView__,`
                                VBAutolayoutConstant: @">=10@999"}`

• distance equal to 0 from item leading to someView trailing

    VBAutolayoutAttributeLeading: @{VBAutolayoutItem: __someView__}

• distance equal to 0 from item leading to container leading

    VBAutolayoutAttributeLeading: @"0"

How to install

Use CocoaPods

pod 'VBAutolayout'

or

Drag VBAutolayout dir into your project.

You can import "VBAutolayout.h" into precompiled header.

Example

https://gist.github.com/valnoc/7dab86a57e0a8124ceb94905debc4dd6

License

VBAutolayout is available under the MIT license. See the LICENSE file for more info.