only fetch IAMs if app is in the foreground

We want to prevent wasted resources polling for IAMs durning times where
it is unlikely they will be seen. Two changes are being made; 1. ensure
we only poll when the isInForeground is true. 2. poll the first time
the app is foregrounded, incase it is not when the SDK is initialized.

Author: jkasten2

OneSignalSDK/onesignal/in-app-messages/src/main/java/com/onesignal/inAppMessages/internal/InAppMessagesManager.kt

@@ -9,6 +9,7 @@ import com.onesignal.common.exceptions.BackendException
 import com.onesignal.common.modeling.ISingletonModelStoreChangeHandler
 import com.onesignal.common.modeling.ModelChangedArgs
 import com.onesignal.common.threading.suspendifyOnThread
+import com.onesignal.core.internal.application.IApplicationLifecycleHandler
 import com.onesignal.core.internal.application.IApplicationService
 import com.onesignal.core.internal.config.ConfigModel
 import com.onesignal.core.internal.config.ConfigModelStore
@@ -71,7 +72,8 @@ internal class InAppMessagesManager(
     ISingletonModelStoreChangeHandler<ConfigModel>,
     IInAppLifecycleEventHandler,
     ITriggerHandler,
-    ISessionLifecycleHandler {
+    ISessionLifecycleHandler,
+    IApplicationLifecycleHandler {
     private val lifecycleCallback = EventProducer<IInAppMessageLifecycleListener>()
     private val messageClickCallback = EventProducer<IInAppMessageClickListener>()
 
@@ -133,6 +135,7 @@ internal class InAppMessagesManager(
         _lifecycle.subscribe(this)
         _triggerController.subscribe(this)
         _sessionService.subscribe(this)
+        _applicationService.addApplicationLifecycleHandler(this)
 
         suspendifyOnThread {
             _repository.cleanCachedInAppMessages()
@@ -225,6 +228,14 @@ internal class InAppMessagesManager(
 
     // called when a new push subscription is added, or the app id is updated, or a new session starts
     private suspend fun fetchMessages() {
+        // We only want to fetch IAMs if we know the app is in the
+        // foreground, as we don't want to do this for background
+        // events (such as push received), wasting resources for
+        // IAMs that are never shown.
+        if (!_applicationService.isInForeground) {
+            return
+        }
+
         val appId = _configModelStore.model.appId
         val subscriptionId = _subscriptionManager.subscriptions.push.id
 
@@ -869,4 +880,16 @@ internal class InAppMessagesManager(
             .setPositiveButton(android.R.string.ok) { _, _ -> suspendifyOnThread { showMultiplePrompts(inAppMessage, prompts) } }
             .show()
     }
+
+    private var onFocusCalled: Boolean = false
+
+    override fun onFocus() {
+        if (onFocusCalled) return
+        onFocusCalled = true
+        suspendifyOnThread {
+            fetchMessages()
+        }
+    }
+
+    override fun onUnfocused() { }
 }