Motion Bindable

A simple two-way data binding library for RubyMotion.

NOTICE

Version 0.3.0 introduces breaking changes and deprecations. If you're upgrading, please check the release notes.

Installation

Add this line to your application's Gemfile:

gem 'motion_bindable'

And then execute:

$ bundle

If you want to use the default strategies that come with MotionBindable add this to your app_delegate.rb:

def application(application, didFinishLaunchingWithOptions: launch_options)
  MotionBindable::Strategies.apply
  true
end

Terminology

Name	Definition
Object	Refers to the parent object that can have many bindings. Usually a model of some sort.
Binding	The connection between an object and it's bound children. Observes and updates both sides. Represented as a Strategy
Bound	Usually an input object, like a UITextField or a Proc.

Usage

Add include MotionBindable::Bindable to make an object bindable:

# Models

class Item
  include MotionBindable::Bindable
  attr_accessor :name
  attr_accessor :location

  def location
    @address ||= Address.new
  end
end

class Address
  attr_accessor :address
end

In your view controller, you can bind the object to a set of Views or any other object:

class ItemListViewController
  def viewDidLoad
    super
    @name_field = UITextField.alloc.initWithFrame [[110, 60], [100, 26]]
    @name_field.placeholder = "Name"
    view.addSubview @name_field

    @address_field = UITextField.alloc.initWithFrame [[110, 100], [100, 26]]
    @address_field.placeholder = "Address"
    view.addSubview @address_field

    @item = Item.new
  end

  def viewWillAppear(animated)
    @item.bind_attributes({
      name: @name_field,
      location: {
        address: @address_field
      }
    })
  end

  # Recommended: Clean everything up when the view leaves
  def viewWillDisappear(animated)
    @item.unbind_all
  end
end

When @name_field.text or @address_field.text changes, so will your model!

Custom Strategies

The above example uses the MotionBindable::Strategies::UITextField. which comes with MotionBindable. Take a look in lib/motion_bindable/strategies for the available defaults. You can implement your own strategies by extending MotionBindable::Strategy. Please use the existing strategies as a guideline.

Default Strategies

The following strategies come with motion-bindable and are setup when MotionBindable::Strategies.apply is called.

Name	Object Candidates	Direction
MotionBindable::Strategies::UITextField	Any UITextField	Bound <-> Attribute
MotionBindable::Strategies::Proc	Any Proc	Bound --> Attribute
MotionBindable::Strategies::UILabel	Any UILabel	Bound <-- Attribute

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request