Suspend children

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Pending changes
 
+- [#122](https://github.com/bumble-tech/appyx/pull/122) - **Breaking change**: `ChildEntry.ChildMode` is removed, now nodes are always created when a nav model changes (previously default behaviour)
+- [#122](https://github.com/bumble-tech/appyx/pull/122) - **Added**: New `ChildEntry.KeepMode` that allows to destroy nodes that are currently not visible on the screen
 - [#119](https://github.com/bumble-tech/appyx/pull/119) - **Fixed**: Lifecycle observers are invoked in incorrect order (child before parent)
 - [#62](https://github.com/bumble-tech/appyx/pull/62) - **Fixed**: Node is marked with stable annotation making some of the composable functions skippable
 - [#129](https://github.com/bumble-tech/appyx/pull/129) - **Updated**: Removed sealed interface from operations to allow client to define their own

app/src/main/kotlin/com/bumble/appyx/app/composable/Page.kt

@@ -48,7 +48,7 @@ fun Page(
 
         Column(
             modifier = Modifier
-                .weight(0.35f)
+                .weight(0.5f)
         ) {
             Text(
                 text = title,

app/src/main/kotlin/com/bumble/appyx/app/node/onboarding/screen/StatefulNode2.kt

@@ -48,7 +48,8 @@ class StatefulNode2(
             body = "– even when they're not visible. " +
                     "\n\nTry going back to the previous screen! " +
                     "You should see that the counters kept on working in the background, " +
-                    "and changes you made to colours are persisted."
+                    "and changes you made to colours are persisted." +
+                    "\n\nIf this behaviour is not desired you can destroy them by using different KeepMode."
         ) {
             val shape = RoundedCornerShape(16.dp)
 
@@ -72,10 +73,10 @@ class StatefulNode2(
             ) {
                 var counter by remember { mutableStateOf(105) }
                 LaunchedEffect(Unit) {
-                        while (true) {
-                            delay(1000)
-                            counter++
-                        }
+                    while (true) {
+                        delay(1000)
+                        counter++
+                    }
                 }
 
                 Text(

core/src/androidTest/kotlin/com/bumble/appyx/core/plugin/BackPressHandlerTest.kt

@@ -16,12 +16,12 @@ import androidx.compose.ui.unit.dp
 import androidx.lifecycle.Lifecycle
 import androidx.test.espresso.Espresso
 import androidx.test.platform.app.InstrumentationRegistry
+import com.bumble.appyx.Appyx
 import com.bumble.appyx.core.children.nodeOrNull
 import com.bumble.appyx.core.composable.Children
 import com.bumble.appyx.core.modality.BuildContext
 import com.bumble.appyx.core.node.ParentNode
 import com.bumble.appyx.core.node.node
-import com.bumble.appyx.debug.Appyx
 import com.bumble.appyx.navmodel.backstack.BackStack
 import com.bumble.appyx.navmodel.backstack.activeRouting
 import com.bumble.appyx.navmodel.backstack.operation.push

core/src/main/kotlin/com/bumble/appyx/Appyx.kt

@@ -0,0 +1,19 @@
+package com.bumble.appyx
+
+import com.bumble.appyx.core.children.ChildEntry
+
+object Appyx {
+
+    var exceptionHandler: ((Exception) -> Unit)? = null
+    var defaultChildKeepMode: ChildEntry.KeepMode = ChildEntry.KeepMode.KEEP
+
+    fun reportException(exception: Exception) {
+        val handler = exceptionHandler
+        if (handler != null) {
+            handler(exception)
+        } else {
+            throw exception
+        }
+    }
+
+}

core/src/main/kotlin/com/bumble/appyx/core/children/ChildAwareImpl.kt

@@ -5,17 +5,17 @@ import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.LifecycleOwner
 import androidx.lifecycle.coroutineScope
 import com.bumble.appyx.core.lifecycle.isDestroyed
+import com.bumble.appyx.core.navigation.RoutingKey
 import com.bumble.appyx.core.node.Node
 import com.bumble.appyx.core.node.ParentNode
-import com.bumble.appyx.core.navigation.RoutingKey
 import com.bumble.appyx.core.withPrevious
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.launch
 import kotlin.reflect.KClass
 
-class ChildAwareImpl<N: Node> : ChildAware<N> {
+class ChildAwareImpl<N : Node> : ChildAware<N> {
 
     private val callbacks: MutableList<ChildAwareCallbackInfo> = ArrayList()
 
@@ -74,7 +74,7 @@ class ChildAwareImpl<N: Node> : ChildAware<N> {
                 val visitedSet = HashSet<Node>()
                 commonKeys.forEach { key ->
                     val current = value.current[key]
-                    if (current != value.previous[key] && current is ChildEntry.Eager) {
+                    if (current != value.previous[key] && current is ChildEntry.Initialized) {
                         notifyWhenChanged(current.node, nodes, visitedSet)
                         visitedSet.add(current.node)
                     }
@@ -131,11 +131,6 @@ class ChildAwareImpl<N: Node> : ChildAware<N> {
     }
 
     private fun getCreatedNodes(childEntryMap: Map<out RoutingKey<*>, ChildEntry<*>>) =
-        childEntryMap.values.mapNotNull { entry ->
-            when (entry) {
-                is ChildEntry.Eager -> entry.node
-                is ChildEntry.Lazy -> null
-            }
-        }
+        childEntryMap.values.mapNotNull { entry -> entry.nodeOrNull }
 
 }

core/src/main/kotlin/com/bumble/appyx/core/children/ChildEntry.kt

@@ -1,10 +1,8 @@
 package com.bumble.appyx.core.children
 
-import com.bumble.appyx.core.node.Node
-import com.bumble.appyx.core.node.build
-import com.bumble.appyx.core.modality.BuildContext
-import com.bumble.appyx.core.navigation.Resolver
 import com.bumble.appyx.core.navigation.RoutingKey
+import com.bumble.appyx.core.node.Node
+import com.bumble.appyx.core.state.SavedStateMap
 
 // custom equals/hashCode for MutableStateFlow and equality checks
 sealed class ChildEntry<T> {
@@ -20,45 +18,20 @@ sealed class ChildEntry<T> {
         "$key@${javaClass.simpleName}"
 
     /** All public APIs should return this type of child which is ready to work with. */
-    class Eager<T>(
+    class Initialized<T>(
         override val key: RoutingKey<T>,
         val node: Node,
     ) : ChildEntry<T>()
 
-    /** Child representation for Lazy mode. */
-    class Lazy<T>(
+    class Suspended<T>(
         override val key: RoutingKey<T>,
-        private val resolver: Resolver<T>,
-        val buildContext: BuildContext,
-    ) : ChildEntry<T>() {
-        internal fun initialize(): Eager<T> =
-            Eager(key, resolver.resolve(key.routing, buildContext).build())
-    }
-
-    /** When to create child nodes? */
-    enum class ChildMode {
-
-        /** When routing state was changed. */
-        EAGER,
-
-        /** When node rendering was requested. */
-        LAZY,
-
-    }
+        val savedState: SavedStateMap?,
+    ) : ChildEntry<T>()
 
-    companion object {
-        fun <T> create(
-            key: RoutingKey<T>,
-            resolver: Resolver<T>,
-            buildContext: BuildContext,
-            childMode: ChildMode,
-        ): ChildEntry<T> =
-            when (childMode) {
-                ChildMode.EAGER ->
-                    Eager(key, resolver.resolve(key.routing, buildContext).build())
-                ChildMode.LAZY ->
-                    Lazy(key, resolver, buildContext)
-            }
+    /** Keep off-screen nodes in the memory? */
+    enum class KeepMode {
+        KEEP,
+        SUSPEND,
     }
 
 }

core/src/main/kotlin/com/bumble/appyx/core/children/ChildEntryExt.kt

@@ -5,6 +5,6 @@ import com.bumble.appyx.core.node.Node
 val <T> ChildEntry<T>.nodeOrNull: Node?
     get() =
         when (this) {
-            is ChildEntry.Eager -> node
-            is ChildEntry.Lazy -> null
+            is ChildEntry.Initialized -> node
+            is ChildEntry.Suspended -> null
         }