1. Ignorance is Strength
or
How I Learned to Stop
Worrying About XCode
and Objective-C and Learn
to Love iOS Development

2. Start

3. About Me
• Paul Infield-Harm
• Director of Product Development at Cyrus
Innovation
• http://about.me/pinfieldharm

4. http://www.cyrusinnovation.com/

5. About you
• Ruby?
• Objective-C?
• iOS?
• RubyMotion?

6. What’s the point of this
talk?
• I decided to try to learn RubyMotion
without first learning traditional iOS
development in XCode and Objective-C.
• If you’re starting out, you might be
wondering how to start.
• A mix of experience report and tips-and-
tricks
• This is also just about learning something
new.

7. A way to learn
• Understand enough to make something,
however messy
• Make it smaller
• Introduce third-party code
• Start over

8. Final Version

9. The final version
system
http://markforster.squarespace.com/

10. Final Version system
• Keep a list of tasks
• Mark the first item with a dot
• Go down the list until you find an item you want
to do before the closest dotted item above
• Repeat until you reach the end of the list
• Then attend to the tasks in bottom-up order
• Delete completed items, and otherwise move
items to the end when you stop working on them
• When nothing is left dotted, start dotting at the
top again

11. Example
Write slides for meetup
Prepare TPS report
Get a haircut
Contemplate my mortality
Eat some ice cream

12. Example
• Write slides for meetup
Prepare TPS report
• Get a haircut
Contemplate my mortality
• Eat some ice cream

13. Example
• Write slides for meetup
Prepare TPS report
• Get a haircut
Contemplate my mortality
• Eat some ice cream

14. fv app

15. [demo]

16. RubyMotion

17. Here’s what some
rubymotion code looks
like

18. fv source code
https://github.com/cyrusinnovation/fv

19. class TaskImageController < UIImagePickerController
def viewDidLoad
self.sourceType = has_camera? ? UIImagePickerControllerSourceTypeCamera :
UIImagePickerControllerSourceTypePhotoLibrary
self.mediaTypes = [KUTTypeImage]
self.delegate = self
self.allowsImageEditing = false
end
def imagePickerControllerDidCancel(picker)
presentingViewController.dismissModalViewControllerAnimated(true)
end
def imagePickerController(picker, didFinishPickingMediaWithInfo:info)
mediaType = info[UIImagePickerControllerMediaType]
TaskList.shared.add_photo_task(info[UIImagePickerControllerOriginalImage])
presentingViewController.dismissModalViewControllerAnimated(true)
end
def has_camera?
UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceTypeCamera)
end
end

20. class TaskList
TaskListChangedNotification = 'TaskListChanged'
def self.shared
@instance ||= TaskList.new
end
def all_tasks
TaskStore.shared.all_tasks
end
def add_text_task(text)
make_change do
return if text == ''
TaskStore.shared.create_task do |task|
task.date_moved = NSDate.date
task.text = text
task.dotted = false
task.active = false
task.photo = false
end
end
end
def add_photo_task(image)
make_change do
TaskStore.shared.create_task do |task|
task.date_moved = NSDate.date
task.dotted = false
task.active = false
task.photo = true
task.photo_uuid = BubbleWrap.create_uuid
scaled_image = ImageStore.saveImage(image, forTask:task)

21. What is RubyMotion?
• Ruby re-implemented on top of iOS
• Ruby statically compiled
• Terminal-based toolchain
• Keep using your favorite editor
• Amazing community
(slide stolen from Laurent Sansonetti talk “RubyMotion: Ruby in your pocket” by Laurent Sansonett
via http://youtu.be/gG9GTUTI9ys)

22. How is it different from
Ruby?
• added named arguments
• no eval
• no define_method
• no require
• most gems don’t work out of the box

23. Close-reading

24. Basic idea: Really
understand a working
RubyMotion program

25. Pierre Menard, Author
of the Quixote
http://www.coldbacon.com/writing/borges-quixote.html

26. He did not want to compose another Quixote —which is easy— but the Quixote
itself. Needless to say, he never contemplated a mechanical transcription of the
original; he did not propose to copy it. His admirable intention was to produce a
few pages which would coincide—word for word and line for line—with those of
Miguel de Cervantes.
[...]
The first method he conceived was relatively simple. Know Spanish well, recover
the Catholic faith, fight against the Moors or the Turk, forget the history of Europe
between the years 1602 and 1918, be Miguel de Cervantes. Pierre Menard studied
this procedure (I know he attained a fairly accurate command of seventeenth-
century Spanish) but discarded it as too easy. Rather as impossible! my reader will
say. Granted, but the undertaking was impossible from the very beginning and of all
the impossible ways of carrying it out, this was the least interesting. To be, in the
twentieth century, a popular novelist of the seventeenth seemed to him a
diminution. To be, in some way, Cervantes and reach the Quixote seemed less
arduous to him—and, consequently, less interesting—than to go on being Pierre
Menard and reach the Quixote through the experiences of Pierre Menard.

27. Close-reading fv

28. [code]

29. Apple Developer docs
http://developer.apple.com/library/IOs

30. Dash
http://kapeli.com/dash/

31. rubymotion.com docs
http://www.rubymotion.com/developer-center/

32. Translation

33. When you need to
translate
• Making API calls
• Reading/using sample code

34. RubyMotion runtime
guide
http://www.rubymotion.com/developer-center/guides/runtime/

35. Rewriting example:
tableview code

36. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"TimeZoneCell";
TimeZoneCell *timeZoneCell = (TimeZoneCell *)[tableView
dequeueReusableCellWithIdentifier:CellIdentifier];
if (timeZoneCell == nil) {
timeZoneCell = [[[TimeZoneCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier] autorelease];
timeZoneCell.frame = CGRectMake(0.0, 0.0, 320.0, ROW_HEIGHT);
}
Region *region = [displayList objectAtIndex:indexPath.section];
NSArray *regionTimeZones = region.timeZoneWrappers;
[timeZoneCell setTimeZoneWrapper:[regionTimeZones objectAtIndex:indexPath.row]];
return timeZoneCell;
}
http://developer.apple.com/library/ios/#documentation/userexperience/conceptual/TableView_iPhone/TableViewCells/TableViewCells.html

37. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"TimeZoneCell";
TimeZoneCell *timeZoneCell = (TimeZoneCell *)[tableView
dequeueReusableCellWithIdentifier:CellIdentifier];
if (timeZoneCell == nil) {
timeZoneCell = [[[TimeZoneCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier] autorelease];
timeZoneCell.frame = CGRectMake(0.0, 0.0, 320.0, ROW_HEIGHT);
}
Region *region = [displayList objectAtIndex:indexPath.section];
NSArray *regionTimeZones = region.timeZoneWrappers;
[timeZoneCell setTimeZoneWrapper:[regionTimeZones objectAtIndex:indexPath.row]];
return timeZoneCell;
}

38. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"TimeZoneCell";
TimeZoneCell *timeZoneCell = (TimeZoneCell *)[tableView
dequeueReusableCellWithIdentifier:CellIdentifier];
if (timeZoneCell == nil) {
timeZoneCell = [[[TimeZoneCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier] autorelease];
timeZoneCell.frame = CGRectMake(0.0, 0.0, 320.0, ROW_HEIGHT);
}
Region *region = [displayList objectAtIndex:indexPath.section];
NSArray *regionTimeZones = region.timeZoneWrappers;
[timeZoneCell setTimeZoneWrapper:[regionTimeZones objectAtIndex:indexPath.row]];
return timeZoneCell;
}
CellIdentifier = "TimeZoneCell"
def tableView(tableView, cellForRowAtIndexPath:indexPath)
timeZoneCell = tableView.dequeueReusableCellWithIdentifier(CellIdentifier)
if (timeZoneCell == nil) {
timeZoneCell = TimeZoneCell.alloc.initWithStyle(UITableViewCellStyleDefault,
reuseIdentifier:CellIdentifier)
timeZoneCell.frame = CGRectMake(0.0, 0.0, 320.0, ROW_HEIGHT)
}
region = displayList.objectAtIndex(indexPath.section)
regionTimeZones = region.timeZoneWrappers
timeZoneCell.setTimeZoneWrapper(regionTimeZones.objectAtIndex(indexPath.row))
timeZoneCell
end

39. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"TimeZoneCell";
TimeZoneCell *timeZoneCell = (TimeZoneCell *)[tableView
dequeueReusableCellWithIdentifier:CellIdentifier];
if (timeZoneCell == nil) {
timeZoneCell = [[[TimeZoneCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier] autorelease];
timeZoneCell.frame = CGRectMake(0.0, 0.0, 320.0, ROW_HEIGHT);
}
Region *region = [displayList objectAtIndex:indexPath.section];
NSArray *regionTimeZones = region.timeZoneWrappers;
[timeZoneCell setTimeZoneWrapper:[regionTimeZones objectAtIndex:indexPath.row]];
return timeZoneCell;
}
CellIdentifier = "TimeZoneCell"
def tableView(tableView, cellForRowAtIndexPath:indexPath)
timeZoneCell = tableView.dequeueReusableCellWithIdentifier(CellIdentifier) || begin
timeZoneCell = TimeZoneCell.alloc.initWithStyle(UITableViewCellStyleDefault,
reuseIdentifier:CellIdentifier)
timeZoneCell.frame = CGRectMake(0.0, 0.0, 320.0, ROW_HEIGHT)
timeZoneCell
end
region = displayList[indexPath.section]
regionTimeZones = region.timeZoneWrappers
timeZoneCell.timeZoneWrapper = regionTimeZones[indexPath.row]
timeZoneCell
end

40. About 30% reduction in
code size, without
much Rubification

41. This is as much
Objective-C as I
needed to know

42. Wrapper libraries

43. BubbleWrap
A collection of (tested) helpers and wrappers used to wrap
CocoaTouch code and provide more Ruby like APIs.
http://bubblewrap.io/

44. addGestureRecognizer(UITapGestureRecognizer.alloc.initWithTarget(self, action:"handleTap"))
addGestureRecognizer(UISwipeGestureRecognizer.alloc.initWithTarget(self, action:"handleRightSwipe"))
leftRecognizer = UISwipeGestureRecognizer.alloc.initWithTarget(self, action:"handleLeftSwipe")
leftRecognizer.direction = UISwipeGestureRecognizerDirectionLeft
addGestureRecognizer(leftRecognizer)
def handleTap
TaskList.shared.toggle_dotted(taskID)
end
def handleRightSwipe
TaskList.shared.remove_task(taskID) if @active
end
def handleLeftSwipe
TaskList.shared.pause_task(taskID) if @active
end
Before
when_tapped { TaskList.shared.toggle_dotted(taskID) }
when_swiped_right { TaskList.shared.remove_task(taskID) if @active }
when_swiped_left { TaskList.shared.pause_task(taskID) if @active }
After

45. sugarcube
a small library of extensions to the Ruby built-in classes that make it
a little easier - and hopefully more “rubyesque” - to work in Cocoa.
https://github.com/rubymotion/sugarcube

46. Using other people’s
objective-c code

47. Using third-party
libraries
• vendoring
• cocoapods

48. Finding ios libraries
http://www.cocoacontrols.com/

49. cocoapods
(go ye with caution)
http://cocoapods.org/

50. Getting help

51. Find someone who
knows more than you

52. RubyMotion Google
Group
http://groups.google.com/group/rubymotion

53. Stack Overflow

54. My office hours
http://ohours.org/pinfieldharm

55. Thanks
http://www.slideshare.net/pinfieldharm/rubymotion-talk