Initialization in Activity#onCreate() may cause a crash or race condition

Initialization of Amplify in Activity#onCreate() may cause problems in the following scenarios though official documentation guides you to do so. Workaround is at the bottom of this issue.

1. Start Activity and Amplify’s initialization happens

Activity#onCreate()
  Amplify.addPlugin(AWSApiPlugin())
  Amplify.configure(applicationContext)

1. Hit back button

Activity#onDestroy() called

1. Re-launch the App again

Activity#onCreate() called again
  Amplify.addPlugin(AWSApiPlugin())
  Amplify.configure(applicationContext) // this throws AmplifyException

The reason this happens is because Amplify is a singleton object and keeps its state with static boolean configured and will not be subject to GC immediately after Activity#onDestroy() is called. In this way, when Activity#onCreate() is called again, initialization is executed again, and a race condition occurs. The official documentation catches the AmplifyException immediately, but because of this exception the configure per CATEGORIES is not done in Amplify#configure(), the app is obviously not in a good state.

The easiest workaround is to initialize in Application#onCreate(). This is the most realistic way. No race condition occurs because the lifetime of the Amplify object is tied to the life cycle of the Application.

// your custom application
class MyApplication : Application() {
    override fun onCreate() {
        super.onCreate()
        try {
            Amplify.addPlugin(AWSApiPlugin())
            Amplify.configure(applicationContext)
        } catch (e: AmplifyException) {
            Log.e(TAG, e.message)
            throw RuntimeException(e)
        }
    }
}

// don't forget to add your app class in the manifest
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="us.shiroyama.amplifyforandroid">
    <application
        android:name=".MyApplication" />
</manifest>

[MFRamon-zz]

For whoever might be facing this issue right now, I’ve tried initializing the Amplify object from the Application class just as @jamesonwilliams says, the stability of the DataStore request and such on my app has gotten way better when only having this class as a singleton in the lifecycle of my app. instead of instantiating multiple object on each Activity

[TrekSoft]

Yeah I actually have the following language in the couple of documentation pages I wrote - perhaps we should adopt similar language throughout the rest of the documentation:

Add the following imports at the top of your MainActivity and code at the bottom of the onCreate method (ideally this would go in your Application class but this works for getting started quickly)