Adrian Hall

Adrian Hall

Microsoft Program Manager by day; Mobile Developer by night

Recent posts

How developers can authenticate and authorize users with AWS AppSync

June 01, 2018  7 minute read  

AWS AppSync provides four distinct methods of authorizing users to optimize and restrict data being transferred AWS AppSync is a managed GraphQL data service that supports offline and real-time scenarios. The service allows the developer to optimize the data transfer between client and server. Any non-trivial application will need to authenticate users. It’s the only way to identify a distinct real person using the application. That association is required for private data storage and c...

Unit Testing in Android Studio with Kotlin

May 12, 2018  5 minute read  

I made myself a promise a couple of months ago. My next app would be fully unit tested for the non-UI components and fully instrument-tested for the UI components. That’s a tall order, especially since I’m using the latest and greatest Android Studio Canary. I ran into a few problems. Some can’t be solved and some can. Let’s start with a simple test. I’ve got a class that looks this: data class Note(val id: String = UUID.randomUUID().toString()) { var updated: Long = System.currentTimeMil...

Deploy an AWS AppSync GraphQL API with CloudFormation

April 17, 2018  15 minute read  

There are lots of tutorials about creating an AWS AppSync API from the ground up using the console. However, sooner or later, you are going to want to create an API for production. You could, just as simply, point-and-click your way around the console to produce the same API. However, that is fraught with problems. You can’t check that API into source code control, nor can you repeatedly deploy the API. Ultimately, you’ll want to automate your deployments. This article is about how you can ...

Easy EditText content validation with Kotlin

April 11, 2018  3 minute read  

One of the things that I always deal with in my apps is the need to validate the input fields of a form. I can easily do this with this sample fragment of code (for example, for a length check): field.addTextChangeListener(object: TextWatcher { override fun afterTextChanged(s: Editable?) { val content = s?.text.toString() s?.error = if (content.length >= 6) null else "Minimum length = 6" } override fun beforeTextChanged(s: Editable?) { } override fun onTextChanged(s: Edita...

Using dependency injection with Koin

April 06, 2018  6 minute read  

In a recent post, I described how I can do app analytics by using the AWS Mobile SDK and an AWS Mobile Hub project. This is a great way to get usage analytics for your app, but it requires a tight coupling between the provider (the AWS Provider and AnalyticsClient) and the app. You need to initialize the provider early on (preferably in the Application wrapper or the first activity). That causes a tight linkage between the activities where it is used and the client object. This has several i...