Create Single View App

1. Launch Visual Studio.
2. To start the project creation wizard, select Create a new project on the Visual Studio start page. You can also access the new project dialog in the File > New > Project menu.
   
3. Use the search term xamarin and filter the project types in the Create a new project dialog. Select the iOS App (Xamarin) template from the filtered list of options.
   
4. Give your new project the name TipCalculator and select Create.

1. Select the Single View App template.
2. Leave the Device Support as Universal to support both iPad and iPhone devices.
3. Pick your preferred Minimum iOS Version or leave it set to the newest version.
4. Click OK to create the project.
   
   Visual Studio creates and loads a new solution with a single iOS project.
   

Delete boiler plate code

1. Open your TipCalculator solution.
2. Locate ViewController.cs.
3. Right-click and then select Delete.

Add a new class

1. You can add a new class file to the project in two ways:
   • Select Project > Add Class from the menu.
   • Select Add > Class from the project context menu
2. In the Apple category, select Class – the empty class template. Enter MyViewController as the name for your class file.
3. Select Add to create the file and add it to your project.

Inherit from UIViewController

1. Open the new source file.
2. Make sure to set the class constructor to public and update the class to derive from UIViewController.
3. You need to fully qualify the class or add the UIKit namespace using statement to the file.
   C#Copy

   <code class="lang-csharp" data-author-content="using System;
   using UIKit;
   
   namespace TipCalculator
   {
       public class MyViewController : UIViewController
       {
           public MyViewController()
           {
           }
       }
   }
   " style="border: 0px; box-sizing: inherit; direction: ltr; display: block; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; font-size: 1em; line-height: 19px; padding: 0px; position: relative;">using System;
   using UIKit;
   
   namespace TipCalculator
   {
       public class MyViewController : UIViewController
       {
           public MyViewController()
           {
           }
       }
   }
   

Assign a UIWindow

1. Open AppDelegate.cs.
2. Locate the FinishedLaunching method and remove all of the code and comments from within the method.
3. Create a new UIWindow object and assign it. The constructor for UIWindow takes a CGRect structure, which defines the rectangle that the window will cover. You want it to cover the entire device screen so use the static property UIScreen.MainScreen.Bounds as the parameter.
4. Assign the created UIWindow to the existing Window property.
   C#Copy

   <code class="lang-csharp" data-author-content="public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
   {
       // Create a new window instance based on the screen size
       Window = new UIWindow(UIScreen.MainScreen.Bounds);
   }
   " style="border: 0px; box-sizing: inherit; direction: ltr; display: block; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; font-size: 1em; line-height: 19px; padding: 0px; position: relative;">public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
   {
       // Create a new window instance based on the screen size
       Window = new UIWindow(UIScreen.MainScreen.Bounds);
   }
   

Display a view controller

1. Create a new instance of MyViewController and assign it to the Window.RootViewController property. This assignment displays your view controller (and the view it controls) as the initial screen when the app starts.
   C#Copy

   <code class="lang-csharp" data-author-content="public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
   {
       // Create a new window instance based on the screen size
       Window = new UIWindow(UIScreen.MainScreen.Bounds);
   
       // Assign the root view controller
       Window.RootViewController = new MyViewController();
   }
   " style="border: 0px; box-sizing: inherit; direction: ltr; display: block; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; font-size: 1em; line-height: 19px; padding: 0px; position: relative;">public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
   {
       // Create a new window instance based on the screen size
       Window = new UIWindow(UIScreen.MainScreen.Bounds);
   
       // Assign the root view controller
       Window.RootViewController = new MyViewController();
   }
   

Set the primary window

1. To direct iOS to make this new window the primary or key window, you need to call the MakeKeyAndVisible method on the UIWindow object.
2. Return true from the method to finish the implementation.
   C#Copy

   <code class="lang-csharp" data-author-content="public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
   {
       // Create a new window instance based on the screen size
       Window = new UIWindow(UIScreen.MainScreen.Bounds);
   
       // Assign the root view controller
       Window.RootViewController = new MyViewController();
   
       // Make the window visible
       Window.MakeKeyAndVisible();
   
       return true;
   }
   " style="border: 0px; box-sizing: inherit; direction: ltr; display: block; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; font-size: 1em; line-height: 19px; padding: 0px; position: relative;">public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
   {
       // Create a new window instance based on the screen size
       Window = new UIWindow(UIScreen.MainScreen.Bounds);
   
       // Assign the root view controller
       Window.RootViewController = new MyViewController();
   
       // Make the window visible
       Window.MakeKeyAndVisible();
   
       return true;
   }
   

Build and run app

1. Choose iPhoneSimulator from the Solution Platforms dropdown on the Visual Studio toolbar.
   
   With iPhoneSimulator selected, you can now choose from the available simulators installed on the Mac. The available devices and versions might change when Xcode is updated on the Mac.
2. Select any iPhone simulator.
   
   The simulator variations are created and installed through Xcode on your Mac build host. Visual Studio reads the configuration and displays what’s available from the build host you’ve selected. If you don’t see the simulator image you’re looking for, you can create it through Xcode.

Build the application

Start a new Xamarin.iOS project

Choose an iOS project template

Xamarin.iOS project structure

Build your application

Test your application

• Test with the iOS Simulator.
  
  The simulator comes with the iOS SDK and is distributed as part of your Xcode installation. The simulator allows you to select different form factors directly from the toolbar. For example, you can choose to run your app on an iPhone or iPad to see visual design differences.
• Test on a Physical device.
  You can connect an Apple mobile device to your Mac with a USB cable and both IDEs will detect it.
  
  Notice how the configuration option differs from the previous example where a simulator is selected. In this case, you select the iPhone build configuration to create native AOT package. Visual Studio for Mac will automatically select the proper configuration based on the device you’re deploying to.

Requirements for deployment to a device