Create a Xamarin.Android App

Article
06/25/2019

Overview

This tutorial shows you how to add a cloud-based backend service to a Xamarin.Android app. For more information, see What are Mobile Apps.

A screenshot from the completed app is below:

Completing this tutorial is a prerequisite for all other Mobile Apps tutorials for Xamarin.Android apps.

Prerequisites

To complete this tutorial, you need the following prerequisites:

An active Azure account. If you don't have an account, sign up for an Azure trial and get up to 10 free Mobile Apps. For details, see Azure Free Trial.
Visual Studio with Xamarin. See Setup and install for Visual Studio and Xamarin for instructions.

Create an Azure Mobile App backend

Follow these steps to create a Mobile App backend.

Sign in to the Azure portal.
Click Create a resource.
In the search box, type Web App.
In the results list, select Web App from the Marketplace.
Select your Subscription and Resource Group (select an existing resource group or create a new one (using the same name as your app)).
Choose a unique Name of your web app.
Choose the default Publish option as Code.
In the Runtime stack, you need to select a version under ASP.NET or Node. If you are building a .NET backend, select a version under ASP.NET. Otherwise if you are targeting a Node based application, select one of the version from Node.
Select the right Operating System, either Linux or Windows.
Select the Region where you would like this app to be deployed.
Select the appropriate App Service Plan and hit Review and create.
Under Resource Group, select an existing resource group or create a new one (using the same name as your app).
Click Create. Wait a few minutes for the service to be deployed successfully before proceeding. Watch the Notifications (bell) icon in the portal header for status updates.
Once the deployment is completed, click on the Deployment details section and then click on the Resource of Type Microsoft.Web/sites. It will navigate you to the App Service Web App that you just created.
Click on the Configuration blade under Settings and in the Application settings, click on the New application setting button.
In the Add/Edit application setting page, enter Name as MobileAppsManagement_EXTENSION_VERSION and Value as latest and hit OK.

You are all set to use this newly created App Service Web app as a Mobile app.

You have now provisioned an Azure Mobile App backend that can be used by your mobile client applications. Next, download a server project for a simple "todo list" backend and publish it to Azure.

Create a database connection and configure the client and server project

Download the client SDK quickstarts for the following platforms:

iOS (Objective-C)
iOS (Swift)
Android (Java)
Xamarin.iOS
Xamarin.Android
Xamarin.Forms
Cordova
Windows (C#)

Note

If you use the iOS project you need to download "azuresdk-iOS-*.zip" from latest GitHub release. Unzip and add the MicrosoftAzureMobile.framework file to the project's root.
You will have to add a database connection or connect to an existing connection. First, determine whether you’ll create a data store or use an existing one.
- Create a new data store: If you’re going to create a data store, use the following quickstart:
  
  Quickstart: Getting started with single databases in Azure SQL Database
- Existing data source: Follow the instructions below if you want to use an existing database connection
  1. SQL Database Connection String format - Data Source=tcp:{your_SQLServer},{port};Initial Catalog={your_catalogue};User ID={your_username};Password={your_password}
    
    {your_SQLServer} Name of the server, this can be found in the overview page for your database and is usually in the form of “server_name.database.windows.net”. {port} usually 1433. {your_catalogue} Name of the database. {your_username} User name to access your database. {your_password} Password to access your database.
    
    Learn more about SQL Connection String format
  2. Add the connection string to your mobile app In App Service, you can manage connection strings for your application by using the Configuration option in the menu.
    
    To add a connection string:
    1. Click on the Application settings tab.
    2. Click on [+] New connection string.
    3. You will need to provide Name, Value and Type for your connection string.
    4. Type Name as MS_TableConnectionString
    5. Value should be the connecting string you formed in the step before.
    6. If you are adding a connection string to a SQL Azure database choose SQLAzure under type.
Azure Mobile Apps has SDKs for .NET and Node.js backends.
- Node.js backend
  
  If you’re going to use Node.js quickstart app, follow the instructions below.
  1. In the Azure portal, go to Easy Tables, you will see this screen.
  2. Make sure the SQL connection string is already added in the Configuration tab. Then check the box of I acknowledge that this will overwrite all site contents and click the Create TodoItem table button.
  3. In Easy Tables, click the + Add button.
  4. Create a TodoItem table with anonymous access.
- .NET backend
  
  If you’re going to use .NET quickstart app, follow the instructions below.
  1. Download the Azure Mobile Apps .NET server project from the azure-mobile-apps-quickstarts repository.
  2. Build the .NET server project locally in Visual Studio.
  3. In Visual Studio, open Solution Explorer, right-click on ZUMOAPPNAMEService project, click Publish, you will see a Publish to App Service window. If you are working on Mac, check out other ways to deploy the app here.
  4. Select App Service as publish target, then click Select Existing, then click the Publish button at the bottom of the window.
  5. You will need to log into Visual Studio with your Azure subscription first. Select the Subscription, Resource Group, and then select the name of your app. When you are ready, click OK, this will deploy the .NET server project that you have locally into the App Service backend. When deployment finishes, you will be redirected to http://{zumoappname}.azurewebsites.net/ in the browser.

Run the Xamarin.Android app

Open the Xamarin.Android project.
Go to the Azure portal and navigate to the mobile app that you created. On the Overview blade, look for the URL which is the public endpoint for your mobile app. Example - the sitename for my app name "test123" will be https://test123.azurewebsites.net.
Open the file ToDoActivity.cs in this folder - xamarin.android/ZUMOAPPNAME/ToDoActivity.cs. The application name is ZUMOAPPNAME.
In ToDoActivity class, replace ZUMOAPPURL variable with public endpoint above.

const string applicationURL = @"ZUMOAPPURL";

becomes

const string applicationURL = @"https://test123.azurewebsites.net";
Press the F5 key to deploy and run the app.
In the app, type meaningful text, such as Complete the tutorial and then click the Add button.

Data from the request is inserted into the TodoItem table. Items stored in the table are returned by the mobile app backend, and the data appears in the list.

Note

You can review the code that accesses your mobile app backend to query and insert data, which is found in the ToDoActivity.cs C# file.

Troubleshooting

If you have problems building the solution, run the NuGet package manager and update the Xamarin.Android support packages. Quickstart projects might not always include the latest versions.

Please note that all the support packages referenced in your project must have the same version. The Azure Mobile Apps NuGet package has Xamarin.Android.Support.CustomTabs dependency for Android platform, so if your project uses newer support packages you need to install this package with required version directly to avoid conflicts.

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