Continuous Learning for Your iOS App Using App Center

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App development is an iterative process, the work you do on version 2 of an app is largely based on the things you learned from building and releasing version 1. In order for your development efforts to be focused in the right direction, they must be data-driven: your app’s usage data, rather than your personal hunches, should inform your selection of the features and bugs you decide to dedicate your limited amount of time and efforts to. Microsoft Visual Studio App Center’s Continuous Monitoring and Learning features are the best tools to help you learn how your app users use your app, seamlessly centralizing all your Analytics and Crash Reporting needs in a single place, supporting any platform and framework you may need, including iOS, Android, Windows, macOS, Xamarin, and React Native. In this tutorial, we’ll see the different powerful tools it offers you to understand your users’ behavior on the iOS version of your app. Let’s dive in! Note: Your app must target iOS 8.0 or above. You also need Xcode 8+ and CocoaPods. If you’re following this tutorial to integrate the App Center SDK into an existing app cannot use any other crash reporting library.

Create your app in the App Center Portal

(Skip this step if you already created your app in App Center.) App Center needs to know about your app in order to receive and process its usage data, so we’ll create a record for your app in App Center (much like we do in iTunes Connect).

1. Visit appcenter.ms.
2. Sign up for a new account or sign in with GitHub, Microsoft, Facebook, or Google.
3. Once you’re in, click on Add New App, select iOS as the OS, and Objective-C/Swift as the platform.
4. Now that the app is created in App Center, click on it, then click on its Settings section.
5. Note your app’s App Secret on the top right section of the screen, you’ll need it in a little bit.

Adding the App Center SDK

(If you haven’t yet integrated CocoaPods into your Xcode project, close Xcode and run pod init in your project directory) App Center has a modular architecture, which means you can integrate just the feature you’re interested in.

1. Open your project’s Podfile and add this dependency:

   pod 'AppCenter'
   

   That line will integrate both App Center Analytics and Crash Reporting into your app, as this tutorial will cover both. If you wish to specify just one of those services, you could add pod 'AppCenter/Analytics' or pod 'AppCenter/Crashes' as required.
2. Run pod install:

   $ pod install
   Analyzing dependencies
   Downloading dependencies
   Installing AppCenter (1.0.1)
   Generating Pods project
   Integrating client project
   
   [!] Please close any current Xcode sessions and use `MyAppName.xcworkspace` for this project from now on.
   Sending stats
   Pod installation complete! There is 1 dependency from the Podfile and 1 total pod installed.
   

   Run pod repo update if CocoaPods complains that it can’t find a specification for AppCenter.
3. Open your app’s AppDelegate.swift file (if you just integrated CocoaPods, make sure you open the .xcworkspace file instead of the .xcodeproj, and add these lines at the top:

   import AppCenter
   import AppCenterAnalytics
   import AppCenterCrashes
   

4. Look for the didFinishLaunchingWithOptions method and add this line:

   MSAppCenter.start("{App Secret}", withServices: [MSAnalytics.self, MSCrashes.self])
   

   Replace {App Secret} with your app’s App Secret, which you noted down earlier on.

And that’s all you need to do to integrate App Center into your app.

App Center Analytics

We’ll now fast-forward into the future. Your users have been using your app for a little while now, App Center gathered and processed usage data. Let’s take a look at what App Center reports:

Overview Page

This dashboard allows you to see the most important data about your app users at a glance. The Active users section shows you how many unique app installations launched the app in the last day, week (7 calendar days), or month (30 calendar days). Note that you have a graphical representation of the statistic, as well as numerical summaries. So in our example above, the chart seems to show that the number of daily users remained constant throughout the months of September and November, but there was in fact a 136.8% increase in that number. You can verify that by hovering your mouse over the line and reading the numbers at each point in time from the pop-up. Daily sessions per user and Session duration give you information about how many sessions your users carry out in your app, and their duration. App Center defines a “session” as “the time from the app coming to foreground to the last event before going to the background”. The other three sections of the overview page give you crucial data about the language your users have set their device to, the country they use the app from, and which devices and OSes they are using. This data helps you answer important questions about whether your users are adopting your latest app version, if there is a need for a new localization of your app, and what device capabilities are safe for you to generally assume during development.

Custom Events

One powerful feature of Analytics is tracking specific events unique to your app. These are usually (but not necessarily) events triggered by the user. For example, you may want to know when the user taps a specific button. You may also want to know more about the context of when that event happened. In order to track a particular event, use the trackEvent:withProperties method in this way:

MSAnalytics.trackEvent("Viewed Product", withProperties: ["ID": "23432", "Name": "Bacon Burger"])

Make sure to add import AppCenterAnalytics to the top of any source code files calling that method!

Stringly-typed caveats

The App Center SDK distinguishes events based on the String you ascribe to them. In the example above, the event was "Viewed Product", but note that this is a different event than "Product Viewed". If you’ll track the same event from more than one place in your code, it’s a good idea to define these event strings as constants. One of the ways to do this is via a simple AnalyticsConstants class:

class AnalyticsConstants {
    static let ViewedProduct = "Viewed Product"
    static let SuccessfulOrder = "Order Successful"
    // ... etc
}

Which you’d use thus:

MSAnalytics.trackEvent(AnalyticsConstants.ViewedProduct, withProperties: ["ID": "23432", "Name": "Bacon Burger"])

You could also go further and define a trackProductView method in AnalyticsConstants for wrapping the entire MSAnalytics.trackEvent method call.

Viewing Events in App Center

Shortly after that method is called at runtime, you’ll see the event displayed in App Center: App Center keeps track of how many times a specific event was triggered, and differentiates between the same event if it had different contextual values. The Trend refers to how much the count has changed compared to the previous time range. In this case the time range is “Last 30 days” (indicated in the top right corner of the screen), and since we triggered the event just now for the first time and never before in the last 30 days, the trend is +1. We can also see a bigger picture of all the events in our app: This overview will tell you how many times an event has been triggered as well as the number of users who triggered it. Similar to Trend, User change refers to how much the number of users triggering the event has changed compared to the last time range. Per user refers to how many times, on average, users trigger that event.

Exporting to Azure

App Center lets you take this further. If you want even more fine-grained insights from your data, or build your own custom analytics dashboards, App Center allows you to export all your Analytics data into Microsoft Azure. Microsoft Azure is an enterprise-grade cloud computing platform that comes with Application Insights, an even more powerful application performance management and monitoring solution. Among its features are detailed dashboards and performance monitoring solutions using machine learning. To see what’s possible, in App Center, click on Settings then on Export.

App Center Crash Reporting

There are times when, sadly, things in your app don’t go as expected, and… it crashes. The whole point of Crash Reporting is to make sure you’re aware of when your app crashes, gather data about the crash, and ultimately fix its root cause so that it doesn’t happen again. App Center’s Crash Reporting features lets you do just that. Let’s take a look at it. For Crash Reporting functionality to work, ensure that your app isn’t using any other Crash Reporting library.

Setup

1. In Xcode, select your iOS Device as a build target, then do Project –> Archive. The Organizer should open upon successful completion.
2. In the Organizer’s, right-click on the archive and select Show in Finder.
3. Right click in the .xcarchive of your app and select Show Package Contents.
4. You’ll find the dSYM in the dSYM directory:
5. Right-click on it, select Compress…
6. In App Center’s left-hand column, select Crashes, then Symbols, then click on Upload Symbols in the top-right corner.
7. Upload the zip file you just created.
8. Whenever your app crashes, a report will appear in App Center:

Note that crashes may sometimes be reported the next time the app is opened.

Overview of Crash Data

App Center will give you an overview of all crashes in your app. You’ll see how many daily users experience a crash, and how many overall crashes your installs have. Whenever two or more crash reports share a root cause, App Center will group them thus: You’ll see details of the stack trace, as well as which devices and OSes are most affected.

Integrating App Center Crashes with your bug tracker

One of my favorite features of App Center is the tight integration it offers with the bug tracker your team is using. App Center work with Visual Studio Team Services as well as GitHub, and we’re now going to focus on how to integrate App Center with the latter.

1. In the left-hand column of App Center, click Settings, then select Services
2. Select GitHub and authorize App Center to access your GitHub repositories.
3. Select the GitHub repository that corresponds to your app. You can filter the list by using the textfield in the top right of the screen.
4. App Center will automatically create a GitHub issue for every crash instance your app registers. In other words, the same crash won’t be reported more than once.

That’s a wrap!

You can’t control what you can’t measure, and your app is no exception. As we’ve seen, App Center gives you reliable tools to measure your app’s performance when it’s in testers’ and end-users’ hands. It’s easy to integrate, and it gives you a detailed breakdown of your app usage and users out-of-the-box. Defining your own custom events allow you to measure actions that matter to you, and the crash reporting features help you to understand and fix crashes as soon as they come up as a GitHub issue! I hope you enjoy using one of the best tools out there to understand your users and the health of your app.

Frequently Asked Questions (FAQs) about Continuous Learning in iOS App Using App Center