add Tutorial2_3PopBackStackWithResult

Author: SmartToolFactory

Tutorial3-1Navigation/src/main/java/com/smarttoolfactory/tutorial3_1navigation/Tutorial2_3PopBackStackWithResult.kt

@@ -0,0 +1,179 @@
+package com.smarttoolfactory.tutorial3_1navigation
+
+import android.annotation.SuppressLint
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.Button
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import androidx.lifecycle.compose.dropUnlessResumed
+import androidx.navigation.NavBackStackEntry
+import androidx.navigation.NavGraph.Companion.findStartDestination
+import androidx.navigation.compose.NavHost
+import androidx.navigation.compose.composable
+import androidx.navigation.compose.rememberNavController
+import kotlinx.serialization.Serializable
+
+
+sealed class MyNavigation {
+    @Serializable
+    data class Home(
+        val id: Int,
+    ) : MyNavigation()
+
+    @Serializable
+    data object Detail : MyNavigation()
+
+    @Serializable
+    data object Final : MyNavigation()
+}
+
+@SuppressLint("RestrictedApi")
+@Preview
+@Composable
+fun PopUpBackStackWithResultSample() {
+    val navController = rememberNavController()
+
+    NavHost(
+        modifier = Modifier.fillMaxSize(),
+        navController = navController,
+        startDestination = MyNavigation.Home(-1)
+    ) {
+        composable<MyNavigation.Home> { navBackstackEntry: NavBackStackEntry ->
+            val id = navBackstackEntry.savedStateHandle.get<Int>("id") ?: 0
+
+            HomeScreen(
+                id = id,
+                onNavigateToDetail = { navController.navigate(MyNavigation.Detail) }
+            )
+        }
+
+        composable<MyNavigation.Detail> {
+            DetailScreen(
+                onNavigateToFinal = { navController.navigate(MyNavigation.Final) }
+            )
+        }
+
+        composable<MyNavigation.Final> {
+
+            val backStack by navController.currentBackStack.collectAsState()
+
+            FinalScreen(
+                onNavigateBackToHome = { newId ->
+                    val startId = navController.graph.findStartDestination().id
+                    navController.getBackStackEntry(startId).savedStateHandle["id"] = newId
+                    navController.popBackStack(
+                        destinationId = startId,
+                        inclusive = false
+                    )
+
+                    // Alternative for getting NavDestination
+                    /*                    val firstDestination: NavDestination? = backStack.firstOrNull {
+                                            it.destination.hasRoute(MyNavigation.Home::class)
+                                        }?.destination
+
+                                        firstDestination?.let {
+                                            val startId = firstDestination.id
+
+                                            navController.getBackStackEntry(startId).savedStateHandle["id"] = newId
+
+                                            navController.popBackStack(
+                                                destinationId = startId,
+                                                inclusive = false
+                                            )
+                                        }*/
+                }
+            )
+        }
+    }
+}
+
+@Composable
+private fun HomeScreen(id: Int, onNavigateToDetail: () -> Unit) {
+
+    Column(
+        modifier = Modifier.fillMaxSize().padding(16.dp),
+
+        ) {
+        Text("Home Screen Id: $id", fontSize = 32.sp)
+
+        Spacer(Modifier.weight(1f))
+        Button(
+            modifier = Modifier.fillMaxWidth(),
+            onClick = onNavigateToDetail
+        ) {
+            Text("Navigate to detail")
+        }
+    }
+}
+
+@Composable
+private fun DetailScreen(onNavigateToFinal: () -> Unit) {
+    Column(
+        modifier = Modifier.fillMaxSize().padding(16.dp)
+    ) {
+
+        Text("Detail Screen", fontSize = 32.sp)
+        Spacer(Modifier.weight(1f))
+        Button(
+            modifier = Modifier.fillMaxWidth(),
+            onClick = onNavigateToFinal
+        ) {
+            Text("Navigate to Final")
+        }
+    }
+}
+
+@Composable
+private fun FinalScreen(onNavigateBackToHome: (Int) -> Unit) {
+    Column(
+        modifier = Modifier.fillMaxSize().padding(16.dp)
+    ) {
+
+        var newId by remember {
+            mutableIntStateOf(0)
+        }
+        Text("Final Screen", fontSize = 32.sp)
+
+        Spacer(Modifier.height(60.dp))
+
+        OutlinedTextField(
+            modifier = Modifier.fillMaxWidth(),
+            value = newId.toString(),
+            onValueChange = { text ->
+                text.toIntOrNull()?.let {
+                    newId = it
+                }
+            },
+            keyboardOptions = KeyboardOptions(
+                keyboardType = KeyboardType.NumberPassword
+            )
+        )
+        Spacer(Modifier.weight(1f))
+
+        Button(
+            modifier = Modifier.fillMaxWidth(),
+            onClick = dropUnlessResumed {
+                onNavigateBackToHome(newId)
+            }
+        ) {
+            Text("Popup back to Home")
+        }
+    }
+}