Rapid App Development with RubyMotion allows for increased developer productivity by bringing the flexibility of Ruby to iOS and OSX development while directly bridging to Objective-C libraries without intermediate glue code. RubyMotion provides a REPL for working with apps live and making quick tweaks as well as building whole views programmatically. Third party libraries like Ruby Motion Query can further speed up development by providing view management, creation, and data handling capabilities while minimizing pollution of the RubyMotion namespace.

1. Rapid App Development
with RubyMotion
Stefán Hafliðason
http://stefan.haflidason.com
@styrmis
External libraries that make development even easier

2. • Promises increased developer productivity
• Brings the flexibility of Ruby to iOS and OSX development
• Bridges directly to Obj-C libraries: no intermediate glue
code
• A REPL for working with your app live!
• Make tweaks quickly
• Build whole views programmatically on the fly
Why
RubyMotion?

3. RubyMotion +
3rd Party Libs
• Stock RubyMotion makes life (generally) easier
• Like Rails, there’s a healthy (and growing)
ecosystem of libraries
• These libraries can help speed up development
even further
• If the cost of experimenting is reduced, we’re
more likely to try out new ideas, and that’s my
goal.

4. What are we looking for?
• Non-Polluting!
• Zero/Minimal pollution of our current namespace.
• Minimal Magic!
• Because when magic breaks, we’ll need to fix it.
• Allows fallback to ‘plain’ RubyMotion
• There when you need it, unobtrusive when you
don’t.

5. The Libraries
• View management: Ruby Motion Query (RMQ),
MotionKit
• More Ruby-like view creation: ProMotion!
• Core Data: ruby-xcdm + Core Data Query (CDQ)
• Various helpers: BubbleWrap, SugarCube,
MotionAwesome

6. Ruby Motion Query
• “It’s like jQuery for RubyMotion. Stylesheets,
templates, events, and more”
• Supercharges the REPL/console
• Easy to add, access and modify views
• Also: event binding, styling, animation and
more.

7. Layout Experimentation
Quickly laying out 8 table views on the screen (iPad).
Started in the console, then moved code into the app itself.
1
class
RootViewController
<
UIViewController
2
def
viewDidLoad
3
#
Start
by
laying
out
with
RMQ
4
@week
=
UITableView.alloc.init
5
rmq.append(@week).layout({
t:0,
l:0,
w:217,
h:704})
6
7
@monday
=
UITableView.alloc.init
8
rmq.append(@monday).layout({
t:0,
l:221,
w:200,
h:350})
9
10
@tuesday
=
UITableView.alloc.init
11
rmq.append(@tuesday).layout({
t:0,
l:422,
w:200,
h:350})
12
13
#
...
14
15
@saturday
=
UITableView.alloc.init
16
rmq.append(@saturday).layout({
t:354,
l:422,
w:200,
h:350})
17
18
@sunday
=
UITableView.alloc.init
19
rmq.append(@sunday).layout({
t:354,
l:623,
w:200,
h:350})
20
21
#
...
22
end
23
end

8. Wiring it up
Let’s give those tableviews a data source
1
class
TableViewDataSource
2
#
Implement
a
simple
data
source
delegate
3
end
4
5
rmq(UITableView).each
do
|tv|
6
tv.dataSource
=
TableViewDataSource.new
7
end

9. Live Experimentation
Trying out an inverted colour scheme:
1
(main)>
rmq(UITableView).each
do
|tv|
2
(main)>
tv.backgroundColor
=
rmq.color.black
3
(main)>
rmq(tv).find(UITableViewCell).each
do
|cell|
4
(main)>
cell.backgroundColor
=
rmq.color.from_hex("#333")
5
(main)>
cell.textColor
=
rmq.color.from_hex("#EEE")
6
(main)>
end
7
(main)>
end

10. Exploring View Hierarchies
1
(main)>
rmq.log
:tree
2
3
───
UIView
250313120
{l:
0,
t:
64,
w:
1024,
h:
704}
4
├───
UITableView
172116992
{l:
0,
t:
0,
w:
217,
h:
704}
5
│
├───
UITableViewWrapperView
250322496
{l:
0,
t:
0,
w:
217,
h:
704}
6
│
│
├───
UITableViewCell
250561184
{l:
0,
t:
88,
w:
217,
h:
44}
7
│
│
│
├───
UITableViewCellScrollV
250561584
{l:
0,
t:
0,
w:
217,
h:
44}
8
│
│
│
│
├───
UITableViewCellContent
250562720
{l:
0,
t:
0,
w:
217,
h:
43}
9
│
│
│
│
│
├───
UILabel
250563392
{l:
15,
t:
0,
w:
187,
h:
43}
10
│
│
│
│
├───
_UITableViewCellSepara
250564720
{l:
15,
t:
43,
w:
202,
h:
1}
11
│
│
├───
UITableViewCell
250552688
{l:
0,
t:
44,
w:
217,
h:
44}
12
│
│
│
├───
UITableViewCellScrollV
250553088
{l:
0,
t:
0,
w:
217,
h:
44}
13
│
│
│
│
├───
UITableViewCellContent
250554640
{l:
0,
t:
0,
w:
217,
h:
43}
14
│
│
│
│
│
├───
UILabel
250555312
{l:
15,
t:
0,
w:
187,
h:
43}
15
│
│
│
│
├───
_UITableViewCellSepara
250556592
{l:
15,
t:
43,
w:
202,
h:
1}
16
│
│
├───
UITableViewCell
250531888
{l:
0,
t:
0,
w:
217,
h:
44}
17
│
│
│
├───
UITableViewCellScrollV
250533056
{l:
0,
t:
0,
w:
217,
h:
44}
18
│
│
│
│
├───
UITableViewCellContent
250533840
{l:
0,
t:
0,
w:
217,
h:
43}
19
│
│
│
│
│
├───
UILabel
250538544
{l:
15,
t:
0,
w:
187,
h:
43}
20
│
│
│
│
├───
_UITableViewCellSepara
250543888
{l:
15,
t:
43,
w:
202,
h:
1}

11. Useful Helpers
1 # App!
2 !
3 rmq.app.window!
4 rmq.app.delegate!
5 rmq.app.environment!
6 rmq.app.production?!
7 rmq.app.test?!
8 rmq.app.development?!
9 rmq.app.version!
10 rmq.app.name!
11 rmq.app.identifier!
12 rmq.app.resource_path!
13 rmq.app.document_path!
14 !
15
1 # Device!
2 !
3 rmq.device.screen!
4 rmq.device.width # screen width!
5 rmq.device.height # screen height!
6 rmq.device.ipad?!
7 rmq.device.iphone?!
8 rmq.device.four_inch?!
9 rmq.device.retina?!
10 !
11 # return values are :unknown, :portrait,!
12 # :portrait_upside_down, :landscape_left,!
13 # :landscape_right, :face_up, :face_down!
14 rmq.device.orientation!
15 rmq.device.landscape?!
16 rmq.device.portrait?
Why these are not easy to get at in the iOS
SDK is beyond me…

12. 1 class LoginLayout < MotionKit::Layout
2 include LoginStyles
3
4 def layout
5 add UIImageView, :logo do
6 frame [[0, 0], ['100%', :scale]]
7 end
8
9 add UIView, :button_container do
10 frame from_bottom(height: 50, width: '100%')
11 add UIButton, :login_button do
12 background_color superview.backgroundColor
13 frame [[ 10, 5 ], [ 50, parent.height - 10 ]]
14 end
15 end
16
17 add UIView, :inputs do
18 frame x: 0, y: 0, width: '100%', height: '100% - 50'
19 autoresizing_mask :pin_to_top, :flexible_height, :flexible_width
20 add UITextField, :username_input do
21 frame [[10, 10], ['100% - 10', :auto]]
22 end
23 add UITextField, :password_input do
24 frame below(:username_input, margin: 8)
25 end
26 end
27 end
28 end
• Flexible DSL for view
layouts
• Simpler handling of device
rotation
• Support for constraints /
Auto Layout
• Build your own DSL on top

13. ProMotion
1 class HelpScreen < PM::TableScreen
2 title "Table Screen"
3
4 def table_data
5 [{
6 title: "Help",
7 cells: [
8 { title: "About this app", action: :tapped_about },
9 { title: "Log out", action: :log_out }
10 ]
11 }]
12 end
13
14 def tapped_about(args={})
15 open AboutScreen
16 end
17
18 def log_out
19 # Log out!
20 end
21 end
• Aims to remove as much
boilerplate code as possible
• More intuitive, Ruby-style view
controller building
• Built-in classes for common view
types

14. BubbleWrap
• The first major extension library, contains a wide
array of helpers:
• Camera, JSON handling, notifications, key-value
persistence, location API, message API, SMS,
Timers…
• An extremely easy to use HTTP library for
working with remote APIs
• And more!

15. SugarCube: Sugar coating for verbose APIs
1
(main)>
tree
2
0:
.
UIWindow(#d282f80,
[[0.0,
0.0],
[768.0,
1024.0]])
3
1:
`-­‐-­‐
UILayoutContainerView(#9d23f70,
[[0.0,
0.0],
[768.0,
1024.0]])
4
2:
+-­‐-­‐
UINavigationTransitionView(#a28bf30,
[[0.0,
0.0],
[1024.0,
768.0]])
5
3:
|
`-­‐-­‐
UIViewControllerWrapperView(#a2c2b20,
[[0.0,
0.0],
[1024.0,
768.0]])
6
4:
|
`-­‐-­‐
UIView(#a2b23f0,
[[0.0,
64.0],
[1024.0,
704.0]])
7
5:
|
+-­‐-­‐
UITableView(#aa7f200,
[[0.0,
0.0],
[217.0,
704.0]])
1 (main)> a 4 # alias for 'adjust'!
2 => UIView(#a2b23f0, [[0.0, 64.0], [1024.0, 704.0]]), child of
UIViewControllerWrapperView(#a2c2b20)!
3 (main)> d 100 # alias for 'down'!
4 [[0.0, 164.0], [1024.0, 704.0]]!
5 => UIView(#a2b23f0, [[0.0, 164.0], [1024.0, 704.0]]), child of
UIViewControllerWrapperView(#a2c2b20)!
6 (main)> thinner 50!
7 [[0.0, 164.0], [974.0, 704.0]]
Quick aliases for adjusting any view quickly, e.g. up, down, left,
right, thinner, wider, taller, shorter…

16. SugarCube: Sugar coating for verbose APIs
1 (main)> tree root!
2 0: . #<UINavigationController:0x9d243c0>!
3 1: -- #<RootViewController:0x9d24650>!
4 !
5 => #<UINavigationController:0x9d243c0>!
6 (main)> a 1!
7 => #<RootViewController:0x9d24650>!
8 (main)> $sugarcube_view!
9 => #<RootViewController:0x9d24650>!
10 (main)> $sugarcube_view.any_public_method
Works for view controllers too:
Now when testing a particular method you have the
option to simply invoke it directly.

17. MotionAwesome
1
label(:check_square_o,
size:
18,
text:
@items[indexPath.row])
do
|label|
2
view
=
UIView.alloc.initWithFrame(cell.contentView.frame)
3
rmq(label).layout({
l:10,
t:10,
w:200,
h:25
})
4
view.addSubview(label)
5
cell.contentView.addSubview(view)
6
end

18. Core Data and RubyMotion
• No equivalent of Xcode’s visual data modeller
• How do I define my data model?!
• What about versioning?!
• How will I handle migrations?

19. What we need
• Our data model (NSEntityDescriptions +
NSRelationshipDescriptions forming our
NSManagedObject)
• A Core Data Stack (NSManagedObjectModel +
NSPersistentStoreCoordinator +
NSManagedObjectContext)
• A workflow for versioning and migrating
between versions

20. Defining Our Data Model
• We would normally do this in Xcode
• Visual Editor for .xcdatamodel bundles
• Integrated handling of versioning and custom
migration code
• Automatic lightweight (schema) migrations
• How do we achieve this with RubyMotion?

21. Options for RubyMotion
• Handle everything programmatically (low
level)
• Use Xcode to work with .xcdatamodel files,
copy in each time
• Use a Ruby library for creating .xcdatamodel
files

22. Handling Everything
Programmatically
entity = NSEntityDescription.alloc.init
entity.name = 'Task'
entity.managedObjectClassName = 'Task'
entity.properties =
[ 'task_description', NSStringAttributeType,
'completed', NSBooleanAttributeType ].each_slice(2).map do |name, type|
property = NSAttributeDescription.alloc.init
property.name = name
property.attributeType = type
property.optional = false
property
end

23. Handling Everything
Programmatically
entity = NSEntityDescription.alloc.init
entity.name = 'Task'
entity.managedObjectClassName = 'Task'
entity.properties =
[ 'task_description', NSStringAttributeType,
'completed', NSBooleanAttributeType ].each_slice(2).map do |name, type|
property = NSAttributeDescription.alloc.init
property.name = name
property.attributeType = type
property.optional = false
property
end
Not all that bad, but we want to use .xcdatamodel files so
that we can benefit from versioning, automatic schema
migrations…

24. .xcdatamodel files are just
XML
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>!
<model name="" userDefinedModelVersionIdentifier="001"
type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0"
lastSavedToolsVersion="2061" systemVersion="12D78"
minimumToolsVersion="Xcode 4.3" macOSVersion="Automatic"
iOSVersion="Automatic">!
<entity name="Article" syncable="YES">!
<attribute name="title" optional="YES" attributeType="String"
syncable="YES"/>!
<relationship name="author" optional="YES" minCount="1"
maxCount="1" deletionRule="Nullify" destinationEntity="Author"
inverseName="articles" inverseEntity="Article" syncable="YES"/>!
</entity>!
<entity name="Author" syncable="YES">!
<attribute name="name" optional="YES" attributeType="String"
syncable="YES"/>!
<relationship name="articles" optional="YES" minCount="1"
maxCount="1" deletionRule="Nullify" destinationEntity="Article"
inverseName="author" inverseEntity="Author" syncable="YES"/>!
</entity>!
</model>

25. Using a library to generate
.xcdatamodel files (ruby-xcdm)
1 schema "001" do!
2 entity "Article" do!
3 string :body, optional: false!
4 integer32 :length!
5 boolean :published, default: false!
6 datetime :publishedAt, default: false!
7 string :title, optional: false!
8 !
9 belongs_to :author!
10 end!
11 !
12 entity "Author" do!
13 float :fee!
14 string :name, optional: false!
15 has_many :articles!
16 end!
17 end

26. Workflow
• Create schema file in schemas directory, e.g.
schemas/001_initial.rb
• Build the schema
• Add a new schema version, e.g.
002_add_new_fields.rb
• Rebuild the schema
• That’s it!

27. Workflow
$ echo "gem 'ruby-xcdm', '0.0.5'" >> Gemfile
$ bundle install
$ rake schema:build
Generating Data Model learn-xcdm
Loading schemas/001_initial.rb
Writing resources/learn-xcdm.xcdatamodeld/1.xcdatamodel/
contents
$ rake # The default rake task is to run the app in the simulator
(main)> mom = NSManagedObjectModel.mergedModelFromBundles(nil)
=> #<NSManagedObjectModel:0x8fa7690>
(main)> mom.entities.count
=> 2
(main)> mom.entities.first.name
=> "Article"
(main)> mom.entities.first.propertiesByName
=> {"body"=>#<NSAttributeDescription:0x8e5db30>,
"title"=>#<NSAttributeDescription:0x8ea4770>}

28. Advantages of using ruby-
xcdm
• No magic: generates XML from a schema
• Schema versions are fully text-based and
readable, making them well-suited to version
control
• Can compile our versions into .xcdatamodeld
bundles, completely removing dependence on
Xcode

29. Basic Core Data Stack
1 model = NSManagedObjectModel.mergedModelFromBundles(nil)
2
3 store = NSPersistentStoreCoordinator.alloc.initWithManagedObjectModel(model)
4 store_path = File.join(NSHomeDirectory(), 'Documents', 'LearnXcdm.sqlite')
5 store_url = NSURL.fileURLWithPath(store_path)
6
7 options = { NSMigratePersistentStoresAutomaticallyOption => true,
8 NSInferMappingModelAutomaticallyOption => true }
9
10 error_ptr = Pointer.new(:object)
11
12 unless store.addPersistentStoreWithType(NSSQLiteStoreType,
13 configuration: nil,
14 URL: store_url,
15 options: options,
16 error: error_ptr)
17 raise "[ERROR] Failed to create persistent store: #{error_ptr[0].description}"
18 end
19
20 @context = NSManagedObjectContext.alloc.init
21 @context.persistentStoreCoordinator = store

30. Core Data Query
• From the developers of ruby-xcdm and
RubyMotionQuery (RMQ)
• Abstracts away much of the complexity of Core
Data
• All you need is your .xcdatamodeld bundle (that
we just created using ruby-xcdm)

31. Core Data Query in Action
# app/models/task.rb
class Task < CDQManagedObject
end
!
# app/app_delegate.rb
class AppDelegate
include CDQ
!
def application(application,
didFinishLaunchingWithOptions:launchOptions)
cdq.setup
true
end
end

32. Core Data Query in Action
(main)> Task.count
=> 0
(main)> t1 = Task.create(task_description: "Complete presentation")
(main)> t2 = Task.create(task_description: "File tax return")
(main)> cdq.save
=> true
(main)> exit
$ rake
...
(main)> Task.count
=> 2
(main)> t1, t2 = Task.all.array
(main)> t1.task_description
=> "Complete chapter"
(main)> t2.task_description
=> "File tax return"
(main)> t2.destroy
=> #<NSManagedObjectContext:0x914cbe0>
(main)> cdq.save
=> true
(main)> Task.count
=> 1

33. Author.where(:name).eq("Emily")
Author.where(:name).not_equal("Emily")
Author.limit(1)
Author.offset(10)
Author.where(:name).contains("A").offset(10).first
!
# Conjuctions
Author.where(:name).contains("Emily").and.contains("Dickinson")
Author.where(:name).starts_with("E").or(:pub_count).eq(1)
!
# Nested Conjuctions
Author.where(:name).contains("Emily").and(cdq(:pub_count).gt(100).or.lt(10)
)
!
# Relationships
Author.first.publications.offset(2).limit(1)
cdq(emily_dickinson).publications.where(:type).eq('poetry')
!
class Author < CDQManagedObject
scope :prolific, where(:pub_count).gt(50)
end
Core Data Query in Action

34. Curious about Core Data
and RubyMotion?
A book on this is available on
Leanpub, covers how to use the
Core Data stack with RubyMotion
and how to use libraries like
CoreDataQuery to make
developing Core Data-driven apps
easier.

35. RubyMotion
vs
Swift
• Entirely complementary: there’s a place for both
• I will be coding in Swift instead of Obj-C
• Not instead of Ruby(Motion)…
• Same base (LLVM), can use best tool for the job
in each case.

36. Which library?
• Live development: RubyMotionQuery + SugarCube
• View layout and styling: MotionKit
• Project structure: ProMotion
• Core Data: ruby-xcdm + Core Data Query (CDQ)!
• Testing, mocking: motion-stump!
• Anything else: try Sugarcube and BubbleWrap

37. Next Steps
• In the coming weeks I’ll be researching and writing about:
• Libraries that I didn’t cover in depth today such as MotionKit,
ProMotion, BubbleWrap and motion-stump.
• How to best handle heavyweight/data migrations in RubyMotion
(Core Data)
• Deconstructing the one bit of ‘magic’ in Core Data Query
• How to write a ruby gem and contribute to the RubyMotion
ecosystem.
Stefán Hafliðason
http://stefan.haflidason.com
@styrmis