4

I have total 2 screens i.e SplashScreen and BottomNavScreen(with bottom navigation). BottomNavScreen has 2 screens i.e Screen1 and Screen2.

I want to go back to SplashScreen from Screen2 but i was getting this error while navigating to SplashScreen.

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.lool, PID: 8610
    java.lang.IllegalStateException: ViewModelStore should be set before setGraph call
        at androidx.navigation.NavController.setViewModelStore(NavController.kt:2164)
        at androidx.navigation.NavHostController.setViewModelStore(NavHostController.kt:101)
        at androidx.navigation.compose.NavHostKt.NavHost(NavHost.kt:106)
        at androidx.navigation.compose.NavHostKt.NavHost(NavHost.kt:69)
        at com.example.lool.NavigationKt.BottomNav(navigation.kt:34)
        at com.example.lool.screens.Bottom_nav_screenKt$BottomNavScreen$2.invoke(bottom_nav_screen.kt:31)
        at com.example.lool.screens.Bottom_nav_screenKt$BottomNavScreen$2.invoke(bottom_nav_screen.kt:30)
        at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:116)
        at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
        at androidx.compose.material.ScaffoldKt$ScaffoldLayout$1$1$1$bodyContentPlaceables$1.invoke(Scaffold.kt:316)
        at androidx.compose.material.ScaffoldKt$ScaffoldLayout$1$1$1$bodyContentPlaceables$1.invoke(Scaffold.kt:314)
        at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107)
        at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
        at androidx.compose.ui.layout.SubcomposeLayoutState$subcompose$2$1$1.invoke(SubcomposeLayout.kt:241)
        at androidx.compose.ui.layout.SubcomposeLayoutState$subcompose$2$1$1.invoke(SubcomposeLayout.kt:241)
        at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107)
        at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
        at androidx.compose.runtime.ComposerKt.invokeComposable(Composer.kt:3330)
        at androidx.compose.runtime.ComposerImpl$doCompose$2$5.invoke(Composer.kt:2577)
        at androidx.compose.runtime.ComposerImpl$doCompose$2$5.invoke(Composer.kt:2573)
        at androidx.compose.runtime.SnapshotStateKt.observeDerivedStateRecalculations(SnapshotState.kt:540)
        at androidx.compose.runtime.ComposerImpl.doCompose(Composer.kt:2566)
        at androidx.compose.runtime.ComposerImpl.composeContent$runtime_release(Composer.kt:2517)
        at androidx.compose.runtime.CompositionImpl.composeContent(Composition.kt:476)
        at androidx.compose.runtime.Recomposer.composeInitial$runtime_release(Recomposer.kt:727)
        at androidx.compose.runtime.ComposerImpl$CompositionContextImpl.composeInitial$runtime_release(Composer.kt:2980)
        at androidx.compose.runtime.CompositionImpl.setContent(Composition.kt:432)
        at androidx.compose.ui.layout.SubcomposeLayoutState.subcomposeInto(SubcomposeLayout.kt:259)
        at androidx.compose.ui.layout.SubcomposeLayoutState.access$subcomposeInto(SubcomposeLayout.kt:145)
        at androidx.compose.ui.layout.SubcomposeLayoutState$subcompose$2.invoke(SubcomposeLayout.kt:234)
        at androidx.compose.ui.layout.SubcomposeLayoutState$subcompose$2.invoke(SubcomposeLayout.kt:231)
        at androidx.compose.runtime.snapshots.SnapshotStateObserver.withNoObservations(SnapshotStateObserver.kt:144)
        at androidx.compose.ui.node.OwnerSnapshotObserver.withNoSnapshotReadObservation$ui_release(OwnerSnapshotObserver.kt:49)
        at androidx.compose.ui.node.LayoutNode.withNoSnapshotReadObservation$ui_release(LayoutNode.kt:1107)
        at androidx.compose.ui.layout.SubcomposeLayoutState.subcompose(SubcomposeLayout.kt:231)
        at androidx.compose.ui.layout.SubcomposeLayoutState.subcompose(SubcomposeLayout.kt:226)
        at androidx.compose.ui.layout.SubcomposeLayoutState.subcompose$ui_release(SubcomposeLayout.kt:215)
        at androidx.compose.ui.layout.SubcomposeLayoutState$Scope.subcompose(SubcomposeLayout.kt:466)
        at androidx.compose.material.ScaffoldKt$ScaffoldLayout$1$1$1.invoke(Scaffold.kt:314)
        at androidx.compose.material.ScaffoldKt$ScaffoldLayout$1$1$1.invoke(Scaffold.kt:241)
        at androidx.compose.ui.layout.MeasureScope$layout$1.placeChildren(MeasureScope.kt:68)
E/AndroidRuntime:     at androidx.compose.ui.layout.SubcomposeLayoutState$createMeasurePolicy$1$measure$1.placeChildren(SubcomposeLayout.kt:357)
        at androidx.compose.ui.node.LayoutNode$layoutChildren$1.invoke(LayoutNode.kt:925)
        at androidx.compose.ui.node.LayoutNode$layoutChildren$1.invoke(LayoutNode.kt:915)
        at androidx.compose.runtime.snapshots.SnapshotStateObserver.observeReads(SnapshotStateObserver.kt:128)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeReads$ui_release(OwnerSnapshotObserver.kt:75)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeLayoutSnapshotReads$ui_release(OwnerSnapshotObserver.kt:56)
        at androidx.compose.ui.node.LayoutNode.layoutChildren$ui_release(LayoutNode.kt:915)
        at androidx.compose.ui.node.LayoutNode.onNodePlaced$ui_release(LayoutNode.kt:901)
        at androidx.compose.ui.node.InnerPlaceable.placeAt-f8xVGno(InnerPlaceable.kt:94)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50(Placeable.kt:370)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.placeAt-f8xVGno(OuterMeasurablePlaceable.kt:149)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50(Placeable.kt:370)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50$default(Placeable.kt:203)
        at androidx.compose.foundation.layout.BoxKt.placeInBox(Box.kt:186)
        at androidx.compose.foundation.layout.BoxKt.access$placeInBox(Box.kt:1)
        at androidx.compose.foundation.layout.BoxKt$boxMeasurePolicy$1$measure$2.invoke(Box.kt:126)
        at androidx.compose.foundation.layout.BoxKt$boxMeasurePolicy$1$measure$2.invoke(Box.kt:125)
        at androidx.compose.ui.layout.MeasureScope$layout$1.placeChildren(MeasureScope.kt:68)
        at androidx.compose.ui.node.LayoutNode$layoutChildren$1.invoke(LayoutNode.kt:925)
        at androidx.compose.ui.node.LayoutNode$layoutChildren$1.invoke(LayoutNode.kt:915)
        at androidx.compose.runtime.snapshots.SnapshotStateObserver.observeReads(SnapshotStateObserver.kt:128)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeReads$ui_release(OwnerSnapshotObserver.kt:75)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeLayoutSnapshotReads$ui_release(OwnerSnapshotObserver.kt:56)
        at androidx.compose.ui.node.LayoutNode.layoutChildren$ui_release(LayoutNode.kt:915)
        at androidx.compose.ui.node.LayoutNode.onNodePlaced$ui_release(LayoutNode.kt:901)
        at androidx.compose.ui.node.InnerPlaceable.placeAt-f8xVGno(InnerPlaceable.kt:94)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50(Placeable.kt:370)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50$default(Placeable.kt:203)
        at androidx.compose.ui.node.DelegatingLayoutNodeWrapper$measure$1$1.placeChildren(DelegatingLayoutNodeWrapper.kt:123)
        at androidx.compose.ui.node.DelegatingLayoutNodeWrapper.placeAt-f8xVGno(DelegatingLayoutNodeWrapper.kt:111)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50(Placeable.kt:370)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50$default(Placeable.kt:203)
        at androidx.compose.ui.node.DelegatingLayoutNodeWrapper$measure$1$1.placeChildren(DelegatingLayoutNodeWrapper.kt:123)
        at androidx.compose.ui.node.DelegatingLayoutNodeWrapper.placeAt-f8xVGno(DelegatingLayoutNodeWrapper.kt:111)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.placeWithLayer(Placeable.kt:393)
        at androidx.compose.ui.layout.Placeable$PlacementScope.placeWithLayer$default(Placeable.kt:266)
        at androidx.compose.ui.graphics.SimpleGraphicsLayerModifier$measure$1.invoke(GraphicsLayerModifier.kt:221)
E/AndroidRuntime:     at androidx.compose.ui.graphics.SimpleGraphicsLayerModifier$measure$1.invoke(GraphicsLayerModifier.kt:220)
        at androidx.compose.ui.layout.MeasureScope$layout$1.placeChildren(MeasureScope.kt:68)
        at androidx.compose.ui.node.DelegatingLayoutNodeWrapper.placeAt-f8xVGno(DelegatingLayoutNodeWrapper.kt:111)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50(Placeable.kt:370)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50$default(Placeable.kt:203)
        at androidx.compose.ui.node.DelegatingLayoutNodeWrapper$measure$1$1.placeChildren(DelegatingLayoutNodeWrapper.kt:123)
        at androidx.compose.ui.node.DelegatingLayoutNodeWrapper.placeAt-f8xVGno(DelegatingLayoutNodeWrapper.kt:111)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50(Placeable.kt:370)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.placeAt-f8xVGno(OuterMeasurablePlaceable.kt:149)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50(Placeable.kt:370)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50$default(Placeable.kt:203)
        at androidx.compose.foundation.layout.BoxKt.placeInBox(Box.kt:186)
        at androidx.compose.foundation.layout.BoxKt.access$placeInBox(Box.kt:1)
        at androidx.compose.foundation.layout.BoxKt$boxMeasurePolicy$1$measure$2.invoke(Box.kt:126)
        at androidx.compose.foundation.layout.BoxKt$boxMeasurePolicy$1$measure$2.invoke(Box.kt:125)
        at androidx.compose.ui.layout.MeasureScope$layout$1.placeChildren(MeasureScope.kt:68)
        at androidx.compose.ui.node.LayoutNode$layoutChildren$1.invoke(LayoutNode.kt:925)
        at androidx.compose.ui.node.LayoutNode$layoutChildren$1.invoke(LayoutNode.kt:915)
        at androidx.compose.runtime.snapshots.SnapshotStateObserver.observeReads(SnapshotStateObserver.kt:128)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeReads$ui_release(OwnerSnapshotObserver.kt:75)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeLayoutSnapshotReads$ui_release(OwnerSnapshotObserver.kt:56)
        at androidx.compose.ui.node.LayoutNode.layoutChildren$ui_release(LayoutNode.kt:915)
        at androidx.compose.ui.node.LayoutNode.onNodePlaced$ui_release(LayoutNode.kt:901)
        at androidx.compose.ui.node.InnerPlaceable.placeAt-f8xVGno(InnerPlaceable.kt:94)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.placeWithLayer(Placeable.kt:393)
        at androidx.compose.ui.layout.Placeable$PlacementScope.placeWithLayer$default(Placeable.kt:266)
        at androidx.compose.ui.graphics.BlockGraphicsLayerModifier$measure$1.invoke(GraphicsLayerModifier.kt:164)
        at androidx.compose.ui.graphics.BlockGraphicsLayerModifier$measure$1.invoke(GraphicsLayerModifier.kt:163)
        at androidx.compose.ui.layout.MeasureScope$layout$1.placeChildren(MeasureScope.kt:68)
        at androidx.compose.ui.node.DelegatingLayoutNodeWrapper.placeAt-f8xVGno(DelegatingLayoutNodeWrapper.kt:111)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50(Placeable.kt:370)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.placeAt-f8xVGno(OuterMeasurablePlaceable.kt:149)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50(Placeable.kt:370)
        at androidx.compose.ui.layout.Placeable$PlacementScope.place-70tqf50$default(Placeable.kt:203)
        at androidx.compose.foundation.layout.BoxKt.placeInBox(Box.kt:186)
        at androidx.compose.foundation.layout.BoxKt.access$placeInBox(Box.kt:1)
        at androidx.compose.foundation.layout.BoxKt$boxMeasurePolicy$1$measure$5.invoke(Box.kt:167)
E/AndroidRuntime:     at androidx.compose.foundation.layout.BoxKt$boxMeasurePolicy$1$measure$5.invoke(Box.kt:163)
        at androidx.compose.ui.layout.MeasureScope$layout$1.placeChildren(MeasureScope.kt:68)
        at androidx.compose.ui.node.LayoutNode$layoutChildren$1.invoke(LayoutNode.kt:925)
        at androidx.compose.ui.node.LayoutNode$layoutChildren$1.invoke(LayoutNode.kt:915)
        at androidx.compose.runtime.snapshots.Snapshot$Companion.observe(Snapshot.kt:1776)
        at androidx.compose.runtime.snapshots.SnapshotStateObserver.observeReads(SnapshotStateObserver.kt:123)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeReads$ui_release(OwnerSnapshotObserver.kt:75)
        at androidx.compose.ui.node.OwnerSnapshotObserver.observeLayoutSnapshotReads$ui_release(OwnerSnapshotObserver.kt:56)
        at androidx.compose.ui.node.LayoutNode.layoutChildren$ui_release(LayoutNode.kt:915)
        at androidx.compose.ui.node.LayoutNode.onNodePlaced$ui_release(LayoutNode.kt:901)
        at androidx.compose.ui.node.InnerPlaceable.placeAt-f8xVGno(InnerPlaceable.kt:94)
        at androidx.compose.ui.layout.Placeable.access$placeAt-f8xVGno(Placeable.kt:31)
        at androidx.compose.ui.layout.Placeable$PlacementScope.placeWithLayer-aW-9-wM(Placeable.kt:396)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.placeAt-f8xVGno(OuterMeasurablePlaceable.kt:151)
        at androidx.compose.ui.node.OuterMeasurablePlaceable.replace(OuterMeasurablePlaceable.kt:161)
        at androidx.compose.ui.node.LayoutNode.replace$ui_release(LayoutNode.kt:811)
        at androidx.compose.ui.node.MeasureAndLayoutDelegate.measureAndLayout(MeasureAndLayoutDelegate.kt:215)
        at androidx.compose.ui.platform.AndroidComposeView.measureAndLayout(AndroidComposeView.android.kt:510)
        at androidx.compose.ui.platform.AndroidComposeView.dispatchDraw(AndroidComposeView.android.kt:666)
        at android.view.View.draw(View.java:22707)
        at android.view.View.updateDisplayListIfDirty(View.java:21579)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4512)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4485)
        at android.view.View.updateDisplayListIfDirty(View.java:21535)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4512)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4485)
        at android.view.View.updateDisplayListIfDirty(View.java:21535)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4512)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4485)
        at android.view.View.updateDisplayListIfDirty(View.java:21535)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4512)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4485)
        at android.view.View.updateDisplayListIfDirty(View.java:21535)
        at android.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:534)
        at android.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:540)
        at android.view.ThreadedRenderer.draw(ThreadedRenderer.java:616)
        at android.view.ViewRootImpl.draw(ViewRootImpl.java:4457)
        at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:4177)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:3337)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:2145)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8724)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1037)
        at android.view.Choreographer.doCallbacks(Choreographer.java:845)
        at android.view.Choreographer.doFrame(Choreographer.java:780)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1022)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loopOnce(Looper.java:201)
        at android.os.Looper.loop(Looper.java:288)
        at android.app.ActivityThread.main(ActivityThread.java:7813)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)

This is my MainActivity.kt

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            LoolTheme {
                // A surface container using the 'background' color from the theme
                StartNav()
            }
        }
    }
}

This is my Navigation.kt

@Composable
fun StartNav() {
    val navController = rememberNavController();
    val bottomNavController = rememberNavController();

    NavHost(navController = navController, startDestination = "splash_screen") {
        composable("splash_screen") {
            SplashScreen(navController)
        }
        composable("bottom_nav_screen") {
            BottomNavScreen(
                navController = navController,
                bottomNavHostController = bottomNavController
            )
        }
    }
}


@Composable
fun BottomNav(bottomNavController: NavHostController, navController: NavHostController) {
    NavHost(navController = bottomNavController, startDestination = "screen_1") {
        composable("screen_1") {
            Screen1()
        }
        composable("screen_2") {
            Screen2(navController)
        }
    }
}

This is my SplashScreen.kt

@Composable
fun SplashScreen(navController: NavController) {
    LaunchedEffect(key1 = true) {
        delay(2000L)
        navController.navigate("bottom_nav_screen")
    }

    Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
        Text("Splash Screen")
    }
}

This is my BottomNavScreen.kt

var navItems = listOf<NavItem>(
    NavItem(label = "uyguy", route = "screen_1", icon = Icons.Filled.Add),
    NavItem(label = "fvvf", route = "screen_2", icon = Icons.Filled.AddCircle)
)

@Composable
fun BottomNavScreen(
    navController: NavHostController,
    bottomNavHostController: NavHostController,

    ) {
    Scaffold(
        bottomBar = {
            BottomNavBar(items = navItems, navController = bottomNavHostController, onClick = {
                bottomNavHostController.navigate(it.route)
            })
        }
    ) {
        BottomNav(navController = navController, bottomNavController = bottomNavHostController)
    }
}

This is my Screen1.kt and Screen2.kt

@Composable
fun Screen1(){
    Column(
        modifier = Modifier.fillMaxSize(),
        verticalArrangement = Arrangement.Center,
        horizontalAlignment = Alignment.CenterHorizontally,

        ) {
        Text("1st Screen ", fontSize = 64.sp)
    }
}


@Composable
fun Screen2(navController: NavController) {
    Column(
        modifier = Modifier.fillMaxSize(),
        verticalArrangement = Arrangement.Center,
        horizontalAlignment = Alignment.CenterHorizontally,

        ) {
        Text("2nd Screen Logout ", fontSize = 64.sp, modifier = Modifier.clickable {
            navController.navigate("splash_screen") {

            }
        })
    }
}
Phil Dukhov
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Konark Shivam
  • 160
  • 1
  • 7

2 Answers2

6

When you call navigate, by default it adds a new view to the navigation stack. This is not always the expected behavior - your resources will not be freed, and when the user clicks back, he will see the previous screen. I suspect this is not what you expect after logout.

And it's also one of the reasons that leads to your crash - both view from backstack with index 1 and the new view with current index 3 use the same state of the navigation controller.

In such cases, you need to specify some parameter during navigation, such as clearing the navigation stack as follows:

navController.navigate("splash_screen") {
    popUpTo("splash_screen") {
        inclusive = true
    }
}

You can also bring the splash screen out of the stack, for example, when you don't log out, but show the splash screen as some sort of information screen.

Even with this fix, your application still crashes. But the problem seems to be related to the fact that you split the definition of bottomNavHostController with its NavHost, so this NavController is reused when its reuse is not expected.

I'm not sure if this is a bug or an expected behavior. I suggest you report this to see what the maintainers think about it.

The easiest solution is to get rid of the second `NavHost', for example, see about Nested Navigation.

An other solution is to move the bottomNavHostController declaration from StartNav to BottomNavScreen, or just inside composable("bottom_nav_screen") (which is effectively the same thing), so the short fix is as follows:

composable("bottom_nav_screen") {
    val bottomNavHostController = rememberNavController()
    BottomNavScreen(
        navController = navController,
        bottomNavHostController = bottomNavHostController,
    )
}
Phil Dukhov
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  • 220
  • Thanks for your replay but i got the solution so basically i have created 2 navhost because i have some screens with bottomNavbar and some screens without bottomNavbar. In official tutorials also they have used navhost to show screens with bottomNavbar and I got so confused. I did research and came to know that you can hide bottomNavbar in screens you don’t want and now my app is working fine. I will upload updated code. – Konark Shivam Feb 07 '22 at 16:52
  • 1
    @KonarkShivam sure, getting rid of the second `NavHost` is the easiest way. Also see about [Nested Navigation](https://developer.android.com/jetpack/compose/navigation#nested-nav). – Phil Dukhov Feb 08 '22 at 04:29
2

This is my updated code. https://github.com/deadman00069/bottom_nav_jetpack_compose

I have made a scaffold above my navHost where i have created bottomNavbar.

This line will determine whether to show bottomNavBar or not
if (currentRoute !in items) return@Scaffold

MainActivity.kt

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            LoolTheme {
                var navItems = listOf<NavItem>(
                    NavItem(label = "label_1", route = "screen_1", icon = Icons.Filled.Add),
                    NavItem(label = "label_2", route = "screen_2", icon = Icons.Filled.AddCircle)
                )
                val navController = rememberNavController()
                Scaffold(
                    bottomBar = {
                        val items = navItems.map {
                            it.route
                        }
                        val navBackStackEntry by navController.currentBackStackEntryAsState()
                        val currentRoute =
                            navBackStackEntry?.destination?.hierarchy?.first()?.route

                        //to hide bottomNavBar
                        if (currentRoute !in items) return@Scaffold

                        BottomNavBar(
                            items = navItems,
                            navController = navController,
                            onClick = {
                                navController.navigate(it.route)
                            })

                    }
                ) {
                    StartNav(navController)
                }

            }
        }
    }
}

navigation.kt

@Composable
fun StartNav(navController: NavHostController) {

    NavHost(navController = navController, startDestination = "splash_screen") {
        composable("splash_screen") {
            SplashScreen(navController)
        }
        composable("screen_1") {
            Screen1(navController)
        }
        composable("screen_2") {
            Screen2(navController)
        }

        composable("screen_3") {
            Screen3(navController)
        }
    }
}

Splashscreen.kt

@Composable
fun SplashScreen(navController: NavController) {
    LaunchedEffect(key1 = true) {
        delay(2000L)
        navController.navigate("screen_1")
    }

    Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
        Text("Splash Screen")
    }
}

Screen1.kt

@Composable
fun Screen1(navController: NavController) {
    Column(
        modifier = Modifier.fillMaxSize(),
        verticalArrangement = Arrangement.Center,
        horizontalAlignment = Alignment.CenterHorizontally,

        ) {
        Text("1st Screen ", fontSize = 64.sp)
    }
}

Screen2.kt

@Composable
fun Screen2(navController: NavController) {
    Column(
        modifier = Modifier.fillMaxSize(),
        verticalArrangement = Arrangement.Center,
        horizontalAlignment = Alignment.CenterHorizontally,

        ) {
        Text("2nd Screen", fontSize = 64.sp,
            modifier = Modifier.clickable {
                navController.navigate("screen_3") {

                }
            })
    }
}

Screen3.kt

@Composable
fun Screen3(navController: NavController) {
    Column(
        modifier = Modifier.fillMaxSize(),
        verticalArrangement = Arrangement.Center,
        horizontalAlignment = Alignment.CenterHorizontally,

        ) {
        Text("3st Screen ", fontSize = 64.sp, modifier = Modifier.clickable {
            navController.navigate("splash_screen") {
                popUpTo("splash_screen") {
                    inclusive = true
                }
            }
        })
    }
}
Konark Shivam
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