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What is new on Xamarin.iOS
Xamarin Inc
New in Xamarin.iOS• Features added in the last year– Based on the Mono 2.10/Silverlight-ish stack
• Features based on the Beta channel:– Mono 3.0-based stack– SGen GC– Based on the .NET 4.5 API surface
Released
Beta
Visual Studio!Released
F# Support• Functional Programming comes to iOS!
• The pitch is simple:– Fewer bugs– Focus on intent– Reuse C# libraries, experience– More features, less time
Beta
SIZE REDUCTIONS
TweetStation – Reference App• Comprehensive app• Networking• SQL • Background• Retina artwork• Full (unlinked)
MonoTouch.Dialog
TweetStation Size Reduction
4.2.2 5.0.4 5.2.13 5.4.1 6.0.10 iOS 6
6.2.1 6.3.3.2 Async
(Mono3)
6,200
6,600
7,000
7,400
Size in KB
Size in KB
Released
New: SmartLink• By default, all native code is linked-in
• SmartLink merges Mono and System linker– Only code that is directly referenced is included– Caveat: dynamic Objective-C code can fail– Big savings:
Beta
SmartLink effect on Samples
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2,000
4,000
6,000
All codeSmart Linking
Beta
Size Savings
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Couchbase
Datatra
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DropBoxS
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DropBoxS
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DropBoxS
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100,000200,000300,000400,000500,000
Savings
RUNTIME IMPROVEMENTS
Generic Value Type Sharing• Reduces these kinds of errors:
Unhandled Exception: System.ExecutionEngineException: Attempting to JIT compile method
• By generating generics code that can be shared across value types– like reference types today
• Enables more LINQ, RX and other generic-rich apps to run without changes, or without manual static stubs
Beta
Source of the Error• Static compiler is unable to infer that certain
generic methods will be used at runtime with a specific value type.
• Because the instantiations are delayed until runtime.
Beta
Generic Sharing• Consider: List<T>.Add (T x)• If “T” is a reference type:– Code can be shared between all reference types– Only one List<RefType>.Add (RefType x) exists
– Because all reference types use same storage (one pointer).
Beta
Generics and Value Types• Value types use different storage:– byte – 1 byte– int – 4 bytes– long – 8 bytes
• List<byte>.Add (byte x) has different code than List<long>.Add (long x)
Beta
Generic Sharing Today• Using string, Uri, object, int, long on Add:– Generates one shareable for Uri, object, string– Generates one for int– Generates one for long
With new Generic Value Type Sharing• Using string, Uri, object, int, long on Add:– Generates one shareable for Uri, object, string– Generates one for int– Generates one for long– Generates a value-type shareable• Can be used by dynamic users of Add<ValueType>
Beta
Shareable Value Type Generic• Runtime fallback for generic instantiations that
could not be statically computed• Uses a “fat” value type• Generates code that copies “fat” value types• Limitation: large value types can not be shared• You can disable if not needed:– -O=-gsharedvt
Beta
Cost of Value Type Sharing
4.2.25.0.4
5.2.135.4.1
6.0.10 iOS 6 6.2.1
6.3.3.2 Asyn
c ...
VT Shari
ng6,0006,5007,0007,5008,000
Size in KB Size in KB
394 Kb
Today: For TweetStation, the cost is 394kbWe are working to reduce this
Beta
Native Crypto• System.Security.Cryptography now powered
by iOS native CommonCrytpo• Covers – Symmetric crypto– Hash functions
• Hardware accelerated – AES and SHA1 (when plugged)
• Made binaries using crypto/https 100k lighter
Released
SGen• SGen can now be used in production on iOS
• It is no longer slower than Boehm• And much faster on most scenarios
Beta
DEBUGGING AIDS
NSObject.Description• New API that provides Objective-C “ToString”• NSObject.ToString() calls Description• Sometimes overwritten– You can always call NSObject.Description
Released
Helping you write Threaded Apps• UIKit is not thread safe– No major commercial UI toolkit is thread safe– Thread safety is just too hard for toolkits
• Very few UIKit methods are thread safe
• During debug mode, you get an exception
Released
UIApplication.CheckForIllegalCrossThreadCalls
• If set, accessing UI elements– Throws UIKitThreadAccessException
• Most UIKit classes/methods• UIViewController implemented outside UIKit
• Checks enabled on Debug, disabled on Release builds– Force use: --force-thread-check– Force removal: --disable-thread-check
Released
Thread Safe APIsThread Safe Classes• UIColor• UIDocument• UIFont• UIImage• UIBezierPath• UIDevice
Key Thread Safe Methods• UIApplication.SharedApplica
tion, Background APIs• UIView.Draw
See API docs for [ThreadSafe] attribute
Released
ASYNC
Async Support• Base Class Libraries:
– Expect all the standard Async APIs from .NET BCL– Coverage is .NET 4.5 Complete for BCL
• MonoTouch specific:• 114 methods on the beta
• Easy to turn ObjC methods into Async ones– Details on the Objective-C bindings talk
Beta
Async Synchronization Contexts• For UI thread, we run a UIKit Sync Context
– What you get from the main thread– Code resumes execution on UIKit thread– Using async just works– Transparent
• Grand Central Dispatch Sync Context– If you are running on a GCD DispatchQueue– Will resume/queue execution on the current queue
Beta
General Async Pattern• Methods with the signature:
void Operation (…, Callback onCompletion)
• Become:Task OperationAsync (…)
Beta
API IMPROVEMENTS
More Strong Type Constructors• Where you saw – NSDictionary options
• We now support strongly typed overloads– Give preference to strongly typed overloads– Reduce errors– Trips to the documentation– Unintended effects
Released
Screen Capture• To capture UIKit views:– UIScreen.Capture ()
• To capture OpenGL content:– iPhoneOSGameView.Capture ()
Released
UIGestureRecognizersBeforevoid Setup (){ var pan= new UIPanGestureRecognizer (
this, new Selector (”panHandler")); view.AddGestureRecognizer (pan);}
[Export(”panHandler")]void PanImage (UIPanGestureRecognizer rec){
// handle pan}
Problems:• Error prone: Parameter of PanImage must be right type• No checking (mismatch in selector names)
Nowvoid Setup (){ var pan = new UIPanGestureRecognizer (PanImage); view.AddGestureRecognizer (pan);}
void PanImage (UIPanGestureRecognizer rec){ // handle pan}
Pros:• Compiler enforced types• No selectors to deal with
Released
UIAppearance• Previously:
var appearance = CustomSlider.Appearance;appearance.SetMaxTrackImage (maxImage, UIControlState.Normal);
– Problem: does not work for subclasses
• Now:var appearance = CustomSlider.GetAppearance<CustomSlider> ();appearance.SetMaxTrackImage (maxImage, UIControlState.Normal);
Released
Notifications• Used in iOS/OSX to broadcast messages– Untyped registration– Notification payload is an untyped NSDictionary
• Typically require a trip to the docs:– To find out which notifications exist– To find what keys exist in the dictionary payload– To find out the types of the values in dictionary
Released
Xamarin.iOS Notifications• Discoverable, nested “Notifications class”• For example: UIKeyboard.Notifications• Pattern:– Static method ObserveXXX– Returns observer token– Calling Dispose() on observer unregisters interest
Released
Example – Full Code Completionnotification = UIKeyboard.Notifications.ObserveDidShow ((sender, args) => {
// Access strongly typed args Console.WriteLine ("Notification: {0}", args.Notification);
// RectangleF values Console.WriteLine ("FrameBegin", args.FrameBegin); Console.WriteLine ("FrameEnd", args.FrameEnd);
// double Console.WriteLine ("AnimationDuration", args.AnimationDuration);
// UIViewAnimationCurve Console.WriteLine ("AnimationCurve", args.AnimationCurve);});
// To stop listening:notification.Dispose ();
Released
NSAttributedString• On iOS 5:– Introduced for use in CoreText
• On iOS 6:– It became ubiquitous on UIKit– UIKit views use it everywhere
• Cumbersome to create
Released
NSAttributedString• Standard Objective-C esque approach:
//// This example shows how to create an NSAttributedString for// use with UIKit using NSDictionaries//var dict = new NSMutableDictionary () { { NSAttributedString.FontAttributeName, UIFont.FromName ("HoeflerText-Regular", 24.0f), }, { NSAttributedString.ForegroundColorAttributeName, UIColor.Black }};
• Error prone:– Get right values for keys– Get right types for values– Requires documentation trips
Released
NSAttributedString – C# 4 stylevar text = new NSAttributedString ( "Hello, World", font: UIFont.FromName ("HoeflerText-Regular", 24.0f), foregroundColor: UIColor.Red);
• Uses C# named parameters• Uses C# optional parameter processing• Use as many (or few) as you want
Released
AudioToolbox, AudioUnit, CoreMidi• Completed MIDI support
– Our CoreMIDI binding is OO, baked into system– Equivalent to what 3rd party APIs people use
• AudioUnit– Now complete supported (since 6.2)– Full API coverage
• AudioToolbox– Improved support for multiple audio channels– Strongly typed APIs
Released
CFNetwork-powered HttpClient• Use Apple’s CFNetwork for your HttpClient
– Avoid StartWWAN (Url call)– Turns on Radio for you – Integrates with Async
• Replace:var client = new HttpClient ()
• With:var client = new HttpClient (new CFNetworkHandler ())
Beta
New Dispose Semantics• Changes in NSObject() Dispose• If native code references object:– Managed object is kept functional– Actual shut down happens when native code
releases the reference.• Allows Dispose() of objects that might still be
used by the system.
Released
Razor Integration• Sometimes you want to generate HTML• Razor offers a full template system– Blend HTML and C#– Code completion in HTML
• Easily pass parameters from C# to Template
Released
New File -> Text Template -> RazorReleased
Razor• Creating template, passing data:
– Model property, typed in cshtml filevar template = new HtmlReport () { Model = data };
• Run:class HtmlReport {
string GenerateString () void Generate (TextWriter writer)}
Released
THANK YOU
