Fix iOS lifecycle

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## Pending changes
 
-–
+- [#670](https://github.com/bumble-tech/appyx/pull/670) - Fixes ios lifecycle
 
 ---
 

appyx-navigation/common/src/iosMain/kotlin/com/bumble/appyx/navigation/integration/IosNodeHost.kt

@@ -8,10 +8,10 @@ import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.unit.dp
 import com.bumble.appyx.navigation.node.Node
+import com.bumble.appyx.navigation.platform.LifecycleListener
 import com.bumble.appyx.navigation.platform.LocalOnBackPressedDispatcherOwner
 import com.bumble.appyx.navigation.platform.OnBackPressedDispatcher
 import com.bumble.appyx.navigation.platform.OnBackPressedDispatcherOwner
-import com.bumble.appyx.navigation.platform.PlatformLifecycleRegistry
 import com.bumble.appyx.utils.customisations.NodeCustomisationDirectory
 import com.bumble.appyx.utils.customisations.NodeCustomisationDirectoryImpl
 import kotlinx.cinterop.ExperimentalForeignApi
@@ -30,9 +30,8 @@ fun <N : Node<*>> IosNodeHost(
     customisations: NodeCustomisationDirectory = remember { NodeCustomisationDirectoryImpl(null) },
     factory: NodeFactory<N>,
 ) {
-    val platformLifecycleRegistry = remember {
-        PlatformLifecycleRegistry()
-    }
+    val lifecycleListener = remember { LifecycleListener() }
+
     val mainScreen = UIScreen.mainScreen
     val screenBounds = mainScreen.bounds
 
@@ -58,7 +57,7 @@ fun <N : Node<*>> IosNodeHost(
 
     CompositionLocalProvider(LocalOnBackPressedDispatcherOwner provides onBackPressedDispatcherOwner) {
         NodeHost(
-            lifecycle = platformLifecycleRegistry,
+            lifecycle = lifecycleListener.lifecycle,
             integrationPoint = integrationPoint,
             modifier = modifier,
             customisations = customisations,

appyx-navigation/common/src/iosMain/kotlin/com/bumble/appyx/navigation/platform/LifecycleListener.kt

@@ -0,0 +1,73 @@
+package com.bumble.appyx.navigation.platform
+
+import com.bumble.appyx.navigation.lifecycle.Lifecycle
+import platform.Foundation.NSNotificationCenter
+import platform.Foundation.NSOperationQueue
+import platform.UIKit.UIApplicationDidBecomeActiveNotification
+import platform.UIKit.UIApplicationDidEnterBackgroundNotification
+import platform.UIKit.UIApplicationWillResignActiveNotification
+import platform.UIKit.UIApplicationWillTerminateNotification
+import platform.darwin.NSObjectProtocol
+
+class LifecycleListener {
+    val lifecycle: PlatformLifecycleRegistry = PlatformLifecycleRegistry()
+
+    private lateinit var didEnterBackgroundNotificationObserver: NSObjectProtocol
+    private lateinit var willResignActiveNotificationObserver: NSObjectProtocol
+    private lateinit var didBecomeActiveNotificationObserver: NSObjectProtocol
+    private lateinit var willTerminateNotificationObserver: NSObjectProtocol
+
+    init {
+        created()
+        startObserving()
+    }
+
+    private fun startObserving() {
+        // Goes to background
+        didEnterBackgroundNotificationObserver = addObserverFor(UIApplicationDidEnterBackgroundNotification) {
+            created()
+        }
+        // Becomes inactive
+        willResignActiveNotificationObserver = addObserverFor(UIApplicationWillResignActiveNotification) {
+            started()
+        }
+        // Gets focus back / Becomes active
+        didBecomeActiveNotificationObserver = addObserverFor(UIApplicationDidBecomeActiveNotification) {
+            resumed()
+        }
+        // Is about to be terminated
+        willTerminateNotificationObserver = addObserverFor(UIApplicationWillTerminateNotification) {
+            destroyed()
+        }
+    }
+
+    private fun addObserverFor(
+        notification: platform.Foundation.NSNotificationName,
+        block: () -> Unit
+    ) : NSObjectProtocol {
+        return NSNotificationCenter.defaultCenter.addObserverForName(
+            name = notification,
+            `object` = null,
+            queue = NSOperationQueue.mainQueue,
+            usingBlock = {
+                block()
+            }
+        )
+    }
+
+    private fun created() {
+        lifecycle.setCurrentState(Lifecycle.State.CREATED)
+    }
+
+    private fun resumed() {
+        lifecycle.setCurrentState(Lifecycle.State.RESUMED)
+    }
+
+    private fun started() {
+        lifecycle.setCurrentState(Lifecycle.State.STARTED)
+    }
+
+    private fun destroyed() {
+        lifecycle.setCurrentState(Lifecycle.State.DESTROYED)
+    }
+}