Building your first android app using Xamarin

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<p> 1. Building your first Android app using Xamarin Gill Cleeren - @gillcleeren 2. Hi, Im Gill! Gill Cleeren MVP and Regional Director .NET Practice Manager @ Ordina Trainer &amp; speaker @gillcleeren 3. Im a Pluralsight author! Courses on Windows 8, social and HTML5 4. Agenda Overview of Xamarin and Xamarin.Android Xamarin.Android fundamentals Creating a detail screen Lists and navigation Navigating from master to detail (Optional) Intro to using Fragments Optimizing the application Preparing for store deployment 5. Targets of this talk Understanding the fundamentals of Android app development with Xamarin See how a fully working app can be built 6. The demo scenario Android Coffee Store Manager List of coffee Navigation to details page 7. DEMO Looking at the finished application 8. Overview of Xamarin and Xamarin.Android 9. Hello Xamarin Xamarin enables developers to reach all major mobile platforms! Native User Interface Native Performance Shared Code Across Platforms C# &amp; .NET Framework Toolset on top of Visual Studio Enables VS to create native iOS and Android apps Commercial product 10. Write Everything in C# iOS, Android, Windows, Windows Phone, Mac Billions of Devices covered! 11. The Xamarin platform Xamarin Xamarin.Android Xamarin.iOS Xamarin Forms 12. Xamarin.Android exposes many extra device types 13. Xamarin.Android Anything you can do in Java/Android can be done in C# and Visual Studio (or Xamarin Studio) with Xamarin! 14. How Xamarin works on Android Mono VM + Java VM execute side-by-side (supports both Dalvik and ART) Mono VM JITs IL into native code and executes most of your code Can utilize native libraries directly as well as .NET BCL 15. A word on code-sharing Xamarin brings development time through the use of code-sharing Possible (currently!) using Shared projects: allows organizing the shared code #if directives for platform specific code PCL include the platforms we want to support Abstract to interfaces where platforms have specific implementations 16. Target architecture for a Xamarin app 17. Preparing for Android development 18. What you need for Xamarin.Android development Xamarin license (Xamarin.Android) PC or Mac Visual Studio or Xamarin Studio Android SDK and Emulators (installed via Xamarin setup) Emulator Device (not really required but...) 19. Installing Xamarin.Android 20. A word on emulators Setup will install some basic emulators for you Theyre great for drinking a lot of coffee 21. Alternatives for the default emulators Possible options Genymotion -Requires VirtualBox under the hood HAXM drivers Android Player from Xamarin Microsoft Android emulator Hyper-V 22. Developing with a device 3 steps Enable Debugging on the Device Install USB Drivers (Windows only) Connect the Device to the Computer 23. Enable device debugging Tap the Build number 7 times to reveal developer options 24. DEMO A quick look at the development setup 25. Xamarin.Android fundamentals 26. File New Project 27. File New Project 28. Fundamental #1: Activities Apps are collections of activities A view == an activity (for now ) Apps dont have an entry point No single code line which is called by the OS Apps start when Android creates one of the classes of the app App then gets loaded into memory 29. Fundamental #1: Activities When opening an application, the OS creates the first Activity Activity is a specific class Defines UI and behaviour for a single task Corresponds to a single app screen App gets loaded in memory OS User launches app Activity Android loads app In memory 30. Fundamental #1: Activities One activity needs to be the entry point for the app: MainLauncher=True 31. Activity lifecycle 32. Activity lifecycle We can of course override these methods OnCreate: Create views, initialize variables, and do other prep work before the user sees the Activity This method is called only once when the Activity is loaded into memory OnResume Perform any tasks that need to happen every time the Activity returns to the device screen OnPause Perform any tasks that need to happen every time the Activity leaves the device screen 33. Activity lifecycle in effect 34. Fundamental #2: Views The layout of the app is contained in *.axml files AXML: Android designer file / Android XML First view of the app is named Main.axml Can be any name really AXML files live in the Resources/layout folder 35. The designer for Xamarin.Android views 36. The designer for Xamarin.Android views 37. View code 38. Connecting and accessing controls from code Linking a view with an activity is done using SetContentView 39. Connecting and accessing controls from code We can name controls using the ID property The Android designer maps the control to the Resource class and assigns it a resource ID The code representation of a control is linked to the visual representation of the control in the designer via the Id property 40. Connecting and accessing controls from code Once we have created the controls, we can access them from code Field name is used for lookup 41. Fundamental #3: Application manifest An Android app contains a manifest file Contains a list of all resources, properties that make up the application Also contains name, list of permissions that the application has received Images Icons *.axml Others Android Manifest file 42. DEMO Creating our first Android application together! 43. Navigation and lists 44. Fundamental #4: ListViews and adapters Used very commonly in Android Common way to present lists of rows Each row is represented using a standard style or customized Consists out of ListView: visual part Adapter: feeds data to ListView 45. Fundamental #4: ListViews and adapters 46. Important classes ListView ListActivity BaseAdapter ArrayAdapter &amp; ArrayAdapter 47. ListActivity and the built-in ArrayAdapter [Activity(Label = "Coffees", MainLauncher = true, Icon = "@drawable/icon")] public class CoffeeScreenActivity: ListActivity { string[] coffees; protected override void OnCreate(Bundle bundle) { base.OnCreate(bundle); coffees= new string[] { "Coffee 1","Coffee 2", "Coffee 3"}; ListAdapter = new ArrayAdapter( this, Android.Resource.Layout.SimpleListItem1, coffees); } } 48. Implementing your own adapter In most cases, the ArrayAdapter wont be enough Well need to create our own adapter Inherits from BaseAdapter Things we need to implement Count: To tell the control how many rows are in the data GetView: To return a View for each row, populated with data. This method has a parameter for the ListView to pass in an existing, unused row for re-use GetItemId: Return a row identifier (typically the row number, although it can be any long value that you like) this[int] indexer: To return the data associated with a particular row number 49. Handling row clicks To handle row clicks, we need to implement OnListItemClick protected override void OnListItemClick(ListView l, View v, int position, long id) { var t = items[position]; //do something } 50. DEMO Adding a ListView and an adapter 51. Customizing the ListView with other row views 52. Customizing the ListView with other row views 53. Customizing the ListView with other row views 54. DEMO Using the built-in row views 55. Creating your own row views Custom row layouts are AXML files in Resources/layout Are loaded by Id using a custom adapter View can contain any number of display classes with custom colors, fonts 56. Creating your own row view 57. Using your custom row view public override View GetView(int position, View convertView, ViewGroup parent) { //custom view var item = items[position]; if (convertView == null) { convertView = context.LayoutInflater.Inflate (Resource.Layout.CoffeeRowView, null); } convertView.FindViewById (Resource.Id.CoffeeImageView).SetImageResource( imageRepository.ImageNameToResourceInt(item.ImageId.ToString())); convertView.FindViewById (Resource.Id.CoffeeNameText).Text = item.CoffeeName; convertView.FindViewById (Resource.Id.PriceText).Text = item.Price.ToString(); return convertView; } 58. DEMO Adding our own custom row view 59. Fundamental #5: Intents An Intent is an abstract concept for some sort of operation that should be performed in Android Navigating to another activity Often, launching an external application (= built-in) with the intent of doing something Make a phone call Launch a URI Map an address An intent often consist out of What the intent is The data needed for the intent Phone number to call 60. Intent of making a phone call ActionCall asks Android for an Activity to make a phone call 61. Intent of navigating to another screen StartActivity can be used to start another activity PutExtra() is used to pass data from one activity to the other var intent = new Intent (); intent.SetClass (this, typeof(CoffeeDetailActivity)); intent.PutExtra ("selectedCoffeeId", t.CoffeeId); StartActivity (intent); 62. Receiving information from the intent protected override void OnCreate (Bundle bundle) { base.OnCreate (bundle); SetContentView (Resource.Layout.Main); var selectedCoffeeId = Intent.Extras.GetInt ("selectedCoffeeId", 0); Coffee coffee = DataService.GetCoffeeById (selectedCoffeeId); } 63. DEMO Navigating from the List to the Detail page 64. Adding Fragments 65. The need for Fragments Larger screen: more complex to build UIs that look good on all screens Layouts which look good on a small screen may not look good on a large tablet screen Android V3.0 introduced Fragments Fragment is a UI module UI gets divided into reusable parts Each part is an separate activity At run time, the Activities themselves will decide which Fragments to use Also work in older versions through Support packages 66. The need for Fragments 67. FragmentManager To help an Activity coordinate and manage all these Fragments, Android introduced a new class called the FragmentManager Each activity has an instance of the FragmentManager Allows finding, adding and removing fragments 68. Adding a fragment to an Activity We can add the Fragment to the Activity in 2 ways Declaratively: Fragments can be used declaratively within .axml layout files by using the tag Programmatically Fragments can also be instantiated dynamically by using the FragmentManager classs API 69. DEMO Refactoring to Fragments 70. Optimizing the application 71. Managing strings in strings.xml We can have Android store string values for us Hello World, Click Me!AndroidCoffeeStoreCoffee name 72. Making the app multi-language 73. Application drawables We can add drawables: application icons Adding all resolutions makes sure the icons look good on all screens Filenames are the same Folder name identifies the resolution 74. Application drawables We can select an image in the project properties This now becomes the icon for the application within Android 75. DEMO Adding resources and drawables to the application 76. Deploying to the store 77. Publishing your work Marketplace is most common option Often, more than one is used (Google Play, Amazon, GetJar) Email or website is often for a more closed distribution Also require less work to prepare the application for distribution Google Play is best known store Allows users to discover, download, rate, and pay for applications by clicking a single icon either on their device or on their computer Google Play also provides tools to assist in the analysis of sales and market trends and to control which devices and users may download an application 78. Summary Xamarin.Android leverages your C# knowledge to build apps for Android Concepts of Android mean a learning curve 79. Thanks! 80. Q&amp;A 81. Building your first Android app using Xamarin Gill Cleeren - @gillcleeren 82. Your feedback is important! Scan the QR Code and let us know via the TechDays App. Laat ons weten wat u van de sessie vindt via de TechDays App! Scan de QR Code. Bent u al lid van de Microsoft Virtual Academy?! Op MVA kunt u altijd iets nieuws leren over de laatste technologie van Microsoft. Meld u vandaag aan op de MVA Stand. MVA biedt 7/24 gratis online training on-demand voor IT- Professionals en Ontwikkelaars. </p>