[#547] Define "results" for the "Up" navigation to deliver result to previous screens

sample-compose/app/src/main/java/co/nimblehq/sample/compose/extensions/SavedStateHandleExt.kt

@@ -0,0 +1,11 @@
+package co.nimblehq.sample.compose.extensions
+
+import androidx.lifecycle.SavedStateHandle
+
+fun <T> SavedStateHandle.getThenRemove(key: String): T? {
+    return if (contains(key)) {
+        val value = get<T>(key)
+        remove<T>(key)
+        value
+    } else null
+}

sample-compose/app/src/main/java/co/nimblehq/sample/compose/ui/AppNavGraph.kt

@@ -11,7 +11,7 @@ import co.nimblehq.sample.compose.ui.base.BaseDestination
 import co.nimblehq.sample.compose.ui.screens.main.mainNavGraph
 
 @Composable
-fun AppNavigation(
+fun AppNavGraph(
     navController: NavHostController,
 ) {
     NavHost(
@@ -44,7 +44,12 @@ fun NavGraphBuilder.composable(
  */
 fun NavHostController.navigate(destination: BaseDestination, parcel: Pair<String, Any?>? = null) {
     when (destination) {
-        is BaseDestination.Up -> navigateUp()
+        is BaseDestination.Up -> {
+            destination.results.forEach { (key, value) ->
+                previousBackStackEntry?.savedStateHandle?.set(key, value)
+            }
+            navigateUp()
+        }
         else -> {
             parcel?.let { (key, value) ->
                 currentBackStackEntry?.savedStateHandle?.set(key, value)

sample-compose/app/src/main/java/co/nimblehq/sample/compose/ui/base/BaseDestination.kt

@@ -2,6 +2,8 @@ package co.nimblehq.sample.compose.ui.base
 
 import androidx.navigation.NamedNavArgument
 
+const val KeyResultOk = "keyResultOk"
+
 abstract class BaseDestination(val route: String = "") {
 
     open val arguments: List<NamedNavArgument> = emptyList()
@@ -10,5 +12,10 @@ abstract class BaseDestination(val route: String = "") {
 
     open var parcelableArgument: Pair<String, Any?> = "" to null
 
-    object Up : BaseDestination()
+    data class Up(val results: HashMap<String, Any> = hashMapOf()) : BaseDestination() {
+
+        fun addResult(key: String, value: Any) = apply {
+            results[key] = value
+        }
+    }
 }

sample-compose/app/src/main/java/co/nimblehq/sample/compose/ui/screens/MainActivity.kt

@@ -4,7 +4,7 @@ import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.navigation.compose.rememberNavController
-import co.nimblehq.sample.compose.ui.AppNavigation
+import co.nimblehq.sample.compose.ui.AppNavGraph
 import co.nimblehq.sample.compose.ui.theme.ComposeTheme
 import dagger.hilt.android.AndroidEntryPoint
 
@@ -15,7 +15,7 @@ class MainActivity : ComponentActivity() {
         super.onCreate(savedInstanceState)
         setContent {
             ComposeTheme {
-                AppNavigation(navController = rememberNavController())
+                AppNavGraph(navController = rememberNavController())
             }
         }
     }

sample-compose/app/src/main/java/co/nimblehq/sample/compose/ui/screens/main/MainNavGraph.kt

@@ -3,8 +3,10 @@ package co.nimblehq.sample.compose.ui.screens.main
 import androidx.navigation.NavGraphBuilder
 import androidx.navigation.NavHostController
 import androidx.navigation.navigation
+import co.nimblehq.sample.compose.extensions.getThenRemove
 import co.nimblehq.sample.compose.model.UiModel
 import co.nimblehq.sample.compose.ui.AppDestination
+import co.nimblehq.sample.compose.ui.base.KeyResultOk
 import co.nimblehq.sample.compose.ui.composable
 import co.nimblehq.sample.compose.ui.navigate
 import co.nimblehq.sample.compose.ui.screens.main.home.HomeScreen
@@ -18,11 +20,14 @@ fun NavGraphBuilder.mainNavGraph(
         route = AppDestination.MainNavGraph.route,
         startDestination = MainDestination.Home.destination
     ) {
-        composable(destination = MainDestination.Home) {
+        composable(destination = MainDestination.Home) { backStackEntry ->
+            val isResultOk = backStackEntry.savedStateHandle
+                .getThenRemove<Boolean>(KeyResultOk) ?: false
             HomeScreen(
                 navigator = { destination ->
                     navController.navigate(destination, destination.parcelableArgument)
-                }
+                },
+                isResultOk = isResultOk,
             )
         }
 

sample-compose/app/src/main/java/co/nimblehq/sample/compose/ui/screens/main/home/HomeScreen.kt

@@ -27,6 +27,7 @@ import kotlinx.coroutines.flow.*
 fun HomeScreen(
     viewModel: HomeViewModel = hiltViewModel(),
     navigator: (destination: BaseDestination) -> Unit,
+    isResultOk: Boolean = false,
 ) {
     val context = LocalContext.current
     viewModel.error.collectAsEffect { e -> e.showToast(context) }
@@ -43,6 +44,12 @@ fun HomeScreen(
         }
     }
 
+    LaunchedEffect(Unit) {
+        if (isResultOk) {
+            context.showToast(context.getString(R.string.message_updated))
+        }
+    }
+
     CameraPermission()
 
     HomeScreenContent(

sample-compose/app/src/main/java/co/nimblehq/sample/compose/ui/screens/main/second/SecondScreen.kt

@@ -1,8 +1,10 @@
 package co.nimblehq.sample.compose.ui.screens.main.second
 
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
+import androidx.compose.material.Button
 import androidx.compose.material.Scaffold
 import androidx.compose.material.Text
 import androidx.compose.runtime.Composable
@@ -13,7 +15,9 @@ import androidx.compose.ui.tooling.preview.Preview
 import androidx.hilt.navigation.compose.hiltViewModel
 import co.nimblehq.sample.compose.R
 import co.nimblehq.sample.compose.ui.base.BaseDestination
+import co.nimblehq.sample.compose.ui.base.KeyResultOk
 import co.nimblehq.sample.compose.ui.common.AppBar
+import co.nimblehq.sample.compose.ui.theme.AppTheme.dimensions
 import co.nimblehq.sample.compose.ui.theme.ComposeTheme
 
 @Composable
@@ -22,11 +26,19 @@ fun SecondScreen(
     navigator: (destination: BaseDestination) -> Unit,
     id: String,
 ) {
-    SecondScreenContent(id)
+    SecondScreenContent(
+        id = id,
+        onUpdateClick = {
+            navigator(BaseDestination.Up().addResult(KeyResultOk, true))
+        },
+    )
 }
 
 @Composable
-private fun SecondScreenContent(id: String) {
+private fun SecondScreenContent(
+    id: String,
+    onUpdateClick: () -> Unit,
+) {
     Scaffold(topBar = {
         AppBar(R.string.second_title_bar)
     }) { paddingValues ->
@@ -35,10 +47,20 @@ private fun SecondScreenContent(id: String) {
                 .fillMaxSize()
                 .padding(paddingValues)
         ) {
-            Text(
-                text = stringResource(R.string.second_id_title, id),
-                modifier = Modifier.align(Alignment.Center)
-            )
+            Column(modifier = Modifier.align(Alignment.Center)) {
+                Text(
+                    text = stringResource(R.string.second_id_title, id),
+                )
+
+                Button(
+                    onClick = { onUpdateClick() },
+                    modifier = Modifier.padding(dimensions.spacingMedium)
+                ) {
+                    Text(
+                        text = stringResource(R.string.second_update)
+                    )
+                }
+            }
         }
     }
 }
@@ -47,6 +69,9 @@ private fun SecondScreenContent(id: String) {
 @Composable
 private fun SecondScreenPreview() {
     ComposeTheme {
-        SecondScreenContent("1")
+        SecondScreenContent(
+            id = "1",
+            onUpdateClick = {},
+        )
     }
 }

sample-compose/app/src/main/res/values/strings.xml

@@ -7,10 +7,12 @@
 
     <string name="second_title_bar">Second</string>
     <string name="second_id_title">ID: %1$s</string>
+    <string name="second_update">Update</string>
 
     <string name="third_title_bar">Third</string>
     <string name="third_data_title">Data: %s</string>
     <string name="third_edit_menu_title">Edit</string>
 
     <string name="message_first_time_launch">This is the first time launch</string>
+    <string name="message_updated">Updated!</string>
 </resources>

template-compose/app/src/main/java/co/nimblehq/template/compose/extensions/SavedStateHandleExt.kt

@@ -0,0 +1,11 @@
+package co.nimblehq.template.compose.extensions
+
+import androidx.lifecycle.SavedStateHandle
+
+fun <T> SavedStateHandle.getThenRemove(key: String): T? {
+    return if (contains(key)) {
+        val value = get<T>(key)
+        remove<T>(key)
+        value
+    } else null
+}

template-compose/app/src/main/java/co/nimblehq/template/compose/ui/AppNavGraph.kt

@@ -11,7 +11,7 @@ import co.nimblehq.template.compose.ui.base.BaseDestination
 import co.nimblehq.template.compose.ui.screens.main.mainNavGraph
 
 @Composable
-fun AppNavigation(
+fun AppNavGraph(
     navController: NavHostController,
 ) {
     NavHost(
@@ -38,7 +38,12 @@ fun NavGraphBuilder.composable(
 
 fun NavHostController.navigate(destination: BaseDestination) {
     when (destination) {
-        is BaseDestination.Up -> navigateUp()
+        is BaseDestination.Up -> {
+            destination.results.forEach { (key, value) ->
+                previousBackStackEntry?.savedStateHandle?.set(key, value)
+            }
+            navigateUp()
+        }
         else -> navigate(route = destination.destination)
     }
 }

template-compose/app/src/main/java/co/nimblehq/template/compose/ui/base/BaseDestination.kt

@@ -8,5 +8,10 @@ abstract class BaseDestination(val route: String = "") {
 
     open var destination: String = route
 
-    object Up : BaseDestination()
+    data class Up(val results: HashMap<String, Any> = hashMapOf()) : BaseDestination() {
+
+        fun addResult(key: String, value: Any) = apply {
+            results[key] = value
+        }
+    }
 }

template-compose/app/src/main/java/co/nimblehq/template/compose/ui/screens/MainActivity.kt

@@ -4,7 +4,7 @@ import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.navigation.compose.rememberNavController
-import co.nimblehq.template.compose.ui.AppNavigation
+import co.nimblehq.template.compose.ui.AppNavGraph
 import co.nimblehq.template.compose.ui.theme.ComposeTheme
 import dagger.hilt.android.AndroidEntryPoint
 
@@ -15,7 +15,7 @@ class MainActivity : ComponentActivity() {
         super.onCreate(savedInstanceState)
         setContent {
             ComposeTheme {
-                AppNavigation(navController = rememberNavController())
+                AppNavGraph(navController = rememberNavController())
             }
         }
     }