Introduction to RubyMotion

Presented to the Canberra Ruby Crew on 19th June 2012.

Image credits:

Bridge photo: http://www.flickr.com/photos/robertjosiah/226473449/sizes/l/in/photostream/
Long cat: http://knowyourmeme.com/photos/2110-longcat
Texts from Xcode: http://www.textfromxcode.com/

Transcript

1. @timriley I’m Tim Riley, I work at Icelab here in Canberra
2. Though I’ve just returned from 8 months in the Philippines. Some of the times, it was like this.
3. But most of the time, it was more like this.
4. But one thing that didn’t change was that I had a lot of this. And it’s the coffee drinking that’s kind of taken me to the point where I can talk to you guys today.
5. It was what led me to help build Decaf Sucks. It’s a Rails app, for café reviews.
6. Last year I build the native iOS app, in Objective-C. My first major iOS project.
7. And today I’ll talk about a bridge between these two worlds of tech: RubyMotion. So what is RubyMotion?
8. RubyMotion And today I’ll talk about a bridge between these two worlds of tech: RubyMotion. So what is RubyMotion?
9. RubyMotion is two things. First, a new implementation of Ruby integrated with the iOS runtime. Includes a static compiler that compiles Ruby into optimized machine code. This part’s proprietary. Second, a set of command line tools create, manage and interactively develop RubyMotion projects. Some of this has been recently open sourced.
10. "RubyMotion" "Objective-C" [@ isEqualToString: @ ]; Let’s compare. RubyMotion builds upon the foundation of Objective-C, starting with the basic object model. Both Ruby and Objective-C both have a common ancestor in Smalltalk, so there's a lot of similarities: Open classes, Single inheritance, Single dynamic message dispatch
11. "RubyMotion" "Objective-C" == Let’s compare. RubyMotion builds upon the foundation of Objective-C, starting with the basic object model. Both Ruby and Objective-C both have a common ancestor in Smalltalk, so there's a lot of similarities: Open classes, Single inheritance, Single dynamic message dispatch
12. [string drawAtPoint:point withFont:font]; Let’s start with message passing
13. string.drawAtPoint(point, withFont:font)
14. string.send(:'drawAtPoint:withFont:', point, font )
15. string.send(:'drawAtPoint:withFont:', point, font )
16. class DrawingProxy def drawAtPoint(point, withFont:font) @str.drawAtPoint(point, withFont:font) end end
17. .h Objective-C interface .h “header” files.
18. @class Foo - (id)instanceMethod; + (id)classMethod; @end One header for every class. We don’t need them any more. In Ruby, the class definitions are the class interfaces. In general, RubyMotion gets rid of a lot of the shitwork in Objective-C. No more repeating yourself.
19. One header for every class. We don’t need them any more. In Ruby, the class definitions are the class interfaces. In general, RubyMotion gets rid of a lot of the shitwork in Objective-C. No more repeating yourself.
20. Shortcuts
21. setFoo: foo=
22. isFoo foo?
23. objectForKey: []
24. setObject:forKey: []=
25. view.hidden = true unless view.hidden? Leads to the expressive Ruby code that we love.
26. Foundation Classes These classes are the base layer of the Cocoa and iOS libraries. RubyMotion translates these for you.
27. MyCustomClass NSObject Kernel
28. String NSMutableString NSString Comparable NSObject Kernel
29. Array NSMutableArray NSArray Enumerable NSObject Kernel
30. Hash NSMutableDictionary NSDictionary Enumerable NSObject Kernel
31. Numeric Comparable NSNumber NSValue NSObject Kernel
32. Time Comparable NSDate NSObject Kernel
33. 'hello'.uppercaseString # => 'HELLO' Building upon the Foundation classes means you have access to their methods. Ruby's native interface for these classes still exists, implemented on their foundation counterparts (eg. NSArray#each). This means you can use the standard Ruby interface to these basic objects, regardless of their origin.
34. Mutable by Default eg., NSString vs NSMutableString. Be careful of the mutability of the objects returned by Cocoa methods.
35. Interfacing with C
36. bool BOOL C Types. RubyMotion translates these for you.
37. bool BOOL true false C Types. RubyMotion translates these for you.
38. char short int long long_long
39. long_long? Wait, long_long? What?
40. long_long? Wait, long_long? What?
41. char short int long long_long
42. char short int long long_long Fixnum Bignum
43. float double These translations are an improvement. Less for you to consider.
44. float double Float These translations are an improvement. Less for you to consider.
45. pt = CGPoint.new pt.x = 100 pt.y = 200 C Structures: a fixed set of labelled values in a single object. These are mapped to classes, which you can use in a number of ways, depending on your context. First, by named setter methods on an already instantiated object.
46. pt = CGPoint.new(100, 200) Or by ordered arguments during instantiation.
47. 'Hello'.drawAtPoint(pt, withFont: font) Here’s how you’d pass that structure as a method argument
48. 'Hello'.drawAtPoint([100, 200], withFont: font) Another shortcut: lets you use an array to pass the structure values in place.
49. 'Hello'.drawAtPoint([100, 200], withFont: font) Another shortcut: lets you use an array to pass the structure values in place.
50. pt = CGMakePoint(100, 200) 'Hello'.drawAtPoint(pt, withFont: font) C Functions are available as methods of the Object class.
51. error_ptr = Pointer.new(:object) C Pointers. This is one time when you really feel that you're outside the comfort of Ruby. A Pointer is a memory address that can point to an object. In iOS SDK, typically used as arguments to return objects by reference.
52. - (id)addObserverForName:(NSString *)name object:(id)obj queue:(NSOperationQueue *)queue usingBlock:(void (^)(NSNotification *))block; C Blocks. A new language extension from Apple.
53. notification_center.addObserverForName( name, object:object, queue:queue, usingBlock:lambda do |notification| # Handle notification here... end ) Should feel pretty natural to Rubyists. Use a Proc objects for the block argument.
54. notification_center.addObserverForName( name, object:object, queue:queue, usingBlock:lambda do |notification| # Handle notification here... end ) Should feel pretty natural to Rubyists. Use a Proc objects for the block argument.
55. Memory Management This is handled for you automatically. It uses a reference counting method, like ARC, but not exactly the same.
56. date = NSDate.alloc.init @date = date If you want to ensure an object's not released, you must create a reference to it, like setting an instance variable. Or set a constant, use a class variable, add the object to a container.
57. Enough with the theory. Let’s get some things up and running. Firstly, Installation: Get Xcode from the Mac App Store
58. Get the Command Line Tools from Xcode’s prefs.
59. Buy and install RubyMotion.
60. Hello world
61. A Bit of UIKit Let's make a more sophisticated hello world, with a UIViewController custom UIView subclass.
62. Interface Builder See http://ianp.org/2012/05/07/rubymotion-and-interface-builder/
63. gem install cocoapods pod setup gem install motion-cocoapods
64. require 'motion-cocoapods' Motion::Project::App.setup do |app| # ... app.pods do dependency 'JSONKit' end end Declare your pod dependencies in the Rakefile. You can also manually include Objective-C library dependencies using `app.vendor_project` directive. And `app.frameworks` allows control over which additional core iOS frameworks you want to use.
65. require 'motion-cocoapods' Motion::Project::App.setup do |app| # ... app.pods do dependency 'JSONKit' end end Declare your pod dependencies in the Rakefile. You can also manually include Objective-C library dependencies using `app.vendor_project` directive. And `app.frameworks` allows control over which additional core iOS frameworks you want to use.
66. RubyMotion Libraries So much innovation has taken place in just the last couple of months.
67. rubymotion/BubbleWrap
68. rubymotion/BubbleWrap
69. rubymotion/BubbleWrap
70. clayallsopp/Routable
71. alloy/MotionData
72. rubymotion/teacup
73. RubyMotion Benefits The expressiveness of Ruby (featured in the library examples we’ve just seen). For us, it’s also a language we already know.
74. describe "Application 'helloworld'" do before do @app = UIApplication.sharedApplication end it "has one window" do @app.windows.size.should == 1 end end Ruby’s strong testing tools and culture. RSpec is built-in.
75. You get to use your own tools. Opening up the toolset choices also means there’s room for innovation here. Think about all the convenience tools we have in Rails: guard, code coverage, testing tools, etc.
76. No more .xcodeproj bullshit. The project structure is simpler and neater, better for collaboration. The single Rakefile expresses your intent much more clearly.
77. No more .xcodeproj bullshit. The project structure is simpler and neater, better for collaboration. The single Rakefile expresses your intent much more clearly.
78. RubyMotion Costs
79. Your own tools aren’t likely as good at Cocoa as Xcode. Not yet, anyway.
80. I’ve spent a lot more time looking up docs in Dash.
81. It's not a magic bullet. You still have to learn iOS APIs.
82. RubyMotion Risks A major 3rd party dependency.
84. The Future Ruby is a fantastic, enabling language. Will RubyMotion allow a "Rails" to evolve for iOS apps?
85. Learning More Free screencast at The Pragmatic Studio, RubyMotion example apps, List of known RubyMotion projects, Cocoa books and learning resources, Big Nerd Ranch examples.
86. @timriley Thanks