sharing up to 80% code for ios, android, and windows platforms, a retail app case study, roy...
TRANSCRIPT
Welcome!
Sharing up to 80% of code building mobile apps for iOS, Android, WP8 and Windows 8
Roy CornelissenIT Architect,Info Support
per,Info Support
Marcel de VriesTechnology Manager
@marcelv
XamarinEvolve2013
Roy CornelissenIT Architect
@roycornelissen
Key takeaways Demos
Architecture Tips & Tricks
Showcase
National web site, aimed at selling the “last available seats” for theatre shows for up to 4 days
No discount or auction site, but a source for inspiration for a fun night out
Order tickets from home, from a terrace or from your hotel room
Demo
MindsetLessons we’ve learned over the years
Stuff that actually works in practiceNot only theoretically
We target iOS, Android and WindowsLeaving out Windows can give a different perspective
on reuse
Showcase: app for a retail startupCurrently being rebranded
What we’ve heard the past few days
Many cross platform talks
Talks on frameworks
This session is about a real app, not
just an example
Important: we also target WindowsVery different UI paradigms, impacts code structure and
level of reuse
Reusable34%
Shared Logic17%Android
10%
iOS8%
Windows Phone10%
Services21%
Shared84%
Specific16%
Per App
Evaluate frameworks
MonoCross
MvvmCross
Roll your own
Frameworks can help speed up
development but they might also limit
your movements by (over)abstraction
Keep as light
as possible
DataSerialization
Caching
SecurityAuthN/AuthZ
Encryption
Data Self Destruction
UtilitiesAnalytics
Logging
Device services
Platform Agnostic API
Application Business Logic
Platform UI
Design Patterns for Reuse
Glue together the
application layers
Navigation frameworks
In our experience, navigation
frameworks yield leaky abstractions.
E.g. PivotView navigation experience
is not the same as menu navigation
via UINavigationController.
Leave UI navigation device
specific
Windows
One pivotview
over multiple
data
representations
Android
Tab bar style
navigation with
separate
activities
Services
Model
ControllerViewModel
Etc.
GPS
Storage
Motion sensors
View
Shared?
Bridge
Shared Platform specific
Model Implementation
We implement the Model as a Singleton
Model Implements INotifyPropertyChanged
Easy to enlist subscribers
Facilitate automatic databinding in XAML
Model contains rich features such as filtering and
advanced selections
Easy to share logic
Model Implementationpublic class MainModel : INotifyPropertyChanged{
private static MainModel _model;private static object _lockHandle = new object();
// Facilitates Windows Phone app resumepublic void RestoreState(MainModel state){
_model = state;}
public static MainModel Current{
get {if (_model == null) {
_model = new MainModel();}return _model;
}}
public IEnumerable<Event> ActualEvents {get {
// E.g. Complex linq stuff}
}}
// Model Usage:
var foo = MainModel.Current.ActualEvents;
Check your water level
Reusable Business Logic
Device SpecificXAML / ValueConverter
Model PropertyValue Transformation
public class ISKEController{
private static ISKEController _instance;private ISKEDomainServicesoap _proxy;
public static ISKEController Current{
get {if (_instance == null) {
_instance = new ISKEController();}return _instance;
}}
private void GetActualEvents (Action<object> OnSuccess, Action<Exception> OnFail){
// do some logic, or service call// use actions to report result or trigger UI action
}}
Shared Controller
UIViewController XAML View Activity
Web Services
SF
SF
SF
Model
GetActualEvents(Action<object> OnSuccess, Action<Exception> OnFail)
PropertyChanged(“Events”);
public void OnFailed(Exception e){
// Do something with error}
public void OnSuccess(object data){
// Do something with data// Notify user
}
Demo
iOS
MonoTouch.CoreLocation
MonoTouch.CoreMotion
MonoTouch.AVFoundation
MonoTouch.AddressBook
MonoTouch.EventKit
…
Android:
Android.Hardware.Sensor
Android.Location
Android.Bluetooth
Android.Nfc
…
Windows Phone:
Microsoft.Devices.Sensors.Gyroscope
Microsoft.Devices.Sensors.Accelerometer
Microsoft.Devices.Sensors.Compass
Microsoft.Devices.Sensors.Motion
…
Partial classes & methods
partial class A
{
// Half of the implementation
}
partial class A
{
// The other half
}
A.cs A.extra.cs
partial class A
{
// Declare the method here
partial void DoSomethingEx();
public void DoSomething()
{
// Some shared logic
DoSomethingEx();
}
}
partial class A
{
// Provide the implementation here
partial void DoSomethingEx()
{
// Do something iOS specific
}
}Can be used from shared
logic
Leaves room for specific
implementation
Always private and returns
void
A.cs A.iOS.cs
Demo
Services – Use soap?
Proxy generation
Silverlight tools: it needs to run on Windows too!
What about bandwidth?
Services – Use REST/JSON?
WebAPI / ServiceStack
More hand coding
Cloud: Azure / Parse / Buddy
Cross platform version control
GitHub, BitBucket
VisualStudio.com
Work items, builds
Demo
C# language tricks
Leverage your tools
Abstractions are good
But don’t over-abstract
Don’t over-engineer
Beware of pitfalls…
