feat: Refactor Navigation Part 4 - Removing crashes from mutableStates

compose/src/main/java/br/zup/com/nimbus/compose/NimbusNavigator.kt

@@ -10,7 +10,7 @@ import java.util.UUID
 
 const val SHOW_VIEW = "showView"
 const val VIEW_URL = "viewUrl"
-const val VIEW_JSON_DESCRIPTION = "json"
+const val JSON = "json"
 const val SHOW_VIEW_DESTINATION_PARAM = "${SHOW_VIEW}?${VIEW_URL}"
 const val SHOW_VIEW_DESTINATION = "$SHOW_VIEW_DESTINATION_PARAM={${VIEW_URL}}"
 

compose/src/main/java/br/zup/com/nimbus/compose/internal/ModalDialog.kt

@@ -2,10 +2,10 @@ package br.zup.com.nimbus.compose.internal
 
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.AnimatedVisibilityScope
-import androidx.compose.animation.ExperimentalAnimationApi
 import androidx.compose.animation.core.tween
 import androidx.compose.animation.slideInVertically
 import androidx.compose.animation.slideOutVertically
+import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
@@ -18,15 +18,14 @@ import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.ExperimentalComposeUiApi
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.window.Dialog
 import androidx.compose.ui.window.DialogProperties
-import br.zup.com.nimbus.compose.CoroutineDispatcherLib
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.launch
-import kotlinx.coroutines.withContext
 
 /**
  * Figured out by trial and error
@@ -40,65 +39,58 @@ private const val DIALOG_BUILD_TIME = 300L
 @Composable
 internal fun ModalTransitionDialog(
     onDismissRequest: () -> Unit,
-    onCanDismissRequest: () -> Boolean,
+    modifier: Modifier = Modifier
+        .fillMaxSize()
+        .background(Color.White),
     dismissOnBackPress: Boolean = true,
-    modifier: Modifier = Modifier.fillMaxSize(),
     modalTransitionDialogHelper: ModalTransitionDialogHelper = ModalTransitionDialogHelper(),
-    content: @Composable (ModalTransitionDialogHelper) -> Unit,
+    content: @Composable (ModalTransitionDialogHelper) -> Unit
 ) {
 
     val onCloseFlow: MutableStateFlow<Boolean> = remember { MutableStateFlow(false) }
     val coroutineScope: CoroutineScope = rememberCoroutineScope()
     val animateContentBackTrigger = remember { mutableStateOf(false) }
 
     LaunchedEffect(key1 = Unit) {
-        withContext(CoroutineDispatcherLib.backgroundPool) {
-            launch {
-                delay(DIALOG_BUILD_TIME)
-                animateContentBackTrigger.value = true
-            }
-            launch {
-                onCloseFlow.collectLatest { shouldClose ->
-                    if(shouldClose)
-                        startDismissWithExitAnimation(animateContentBackTrigger, onDismissRequest)
-                }
+        launch {
+            delay(DIALOG_BUILD_TIME)
+            animateContentBackTrigger.value = true
+        }
+        launch {
+            onCloseFlow.collectLatest { shouldClose ->
+                if(shouldClose)
+                    startDismissWithExitAnimation(animateContentBackTrigger, onDismissRequest)
             }
         }
     }
 
     Dialog(
         onDismissRequest = {
-            coroutineScope.launch(CoroutineDispatcherLib.backgroundPool) {
-                startDismissWithExitAnimation(animateContentBackTrigger,
-                    onDismissRequest,
-                    onCanDismissRequest)
+            coroutineScope.launch {
+                startDismissWithExitAnimation(animateContentBackTrigger, onDismissRequest)
             }
         },
         properties = DialogProperties(usePlatformDefaultWidth = false,
             dismissOnBackPress = dismissOnBackPress,
             dismissOnClickOutside = false)
     ) {
-        Box(modifier = modifier) {
-            AnimatedModalBottomSheetTransition(
-                visible = animateContentBackTrigger.value) {
-                modalTransitionDialogHelper.coroutineScope = coroutineScope
-                modalTransitionDialogHelper.onCloseFlow = onCloseFlow
-                content(modalTransitionDialogHelper)
-            }
+        AnimatedModalBottomSheetTransition(
+            modifier = modifier,
+            visible = animateContentBackTrigger.value) {
+            modalTransitionDialogHelper.onCloseFlow = onCloseFlow
+            modalTransitionDialogHelper.coroutineScope = coroutineScope
+            content(modalTransitionDialogHelper)
         }
     }
 }
 
 private suspend fun startDismissWithExitAnimation(
     animateContentBackTrigger: MutableState<Boolean>,
-    onDismissRequest: () -> Unit,
-    onCanDismissRequest: () -> Boolean = { true },
+    onDismissRequest: () -> Unit
 ) {
-    if (onCanDismissRequest()) {
-        animateContentBackTrigger.value = false
-        delay(ANIMATION_TIME)
-        onDismissRequest()
-    }
+    animateContentBackTrigger.value = false
+    delay(ANIMATION_TIME)
+    onDismissRequest()
 }
 
 /**
@@ -110,27 +102,28 @@ internal class ModalTransitionDialogHelper {
     var coroutineScope: CoroutineScope? = null
     var onCloseFlow: MutableStateFlow<Boolean>? = null
     fun triggerAnimatedClose() {
-        coroutineScope?.launch(CoroutineDispatcherLib.backgroundPool) {
+        coroutineScope?.launch {
             onCloseFlow?.tryEmit(true)
         }
     }
 }
 
 internal const val ANIMATION_TIME = 500L
+internal const val DELAY_SHOW_CONTENT = ANIMATION_TIME + 100L
 
-@OptIn(ExperimentalAnimationApi::class)
 @Composable
 internal fun AnimatedModalBottomSheetTransition(
     visible: Boolean,
-    content: @Composable AnimatedVisibilityScope.() -> Unit,
+    modifier: Modifier = Modifier
+        .fillMaxSize()
+        .background(Color.White),
+    content: @Composable AnimatedVisibilityScope.() -> Unit
 ) {
     var animateContentShowTrigger by remember { mutableStateOf(false) }
     if (visible) {
         LaunchedEffect(key1 = Unit) {
-            withContext(CoroutineDispatcherLib.backgroundPool) {
-                delay(ANIMATION_TIME)
-                animateContentShowTrigger = true
-            }
+            delay(DELAY_SHOW_CONTENT)
+            animateContentShowTrigger = true
         }
     }
     AnimatedVisibility(
@@ -144,8 +137,11 @@ internal fun AnimatedModalBottomSheetTransition(
             targetOffsetY = { fullHeight -> fullHeight }
         ),
         content = {
-            if (animateContentShowTrigger)
-                content()
+            Box(modifier = modifier) {
+                if (animateContentShowTrigger)
+                    content()
+            }
+
         }
     )
 }

compose/src/main/java/br/zup/com/nimbus/compose/internal/NimbusModalView.kt

@@ -2,57 +2,28 @@ package br.zup.com.nimbus.compose.internal
 
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.foundation.layout.padding
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.unit.dp
+import com.zup.nimbus.core.network.ViewRequest
 
 @Composable
 internal fun NimbusModalView(
-    nimbusViewModel: NimbusViewModel,
-    modalParentHelper: ModalTransitionDialogHelper,
+    viewRequest: ViewRequest,
+    onDismiss: () -> Unit,
+    modifier: Modifier = Modifier
+        .fillMaxSize()
+        .background(Color.White)
 ) {
-    var nimbusViewModelModalState: NimbusViewModelModalState by remember {
-        mutableStateOf(NimbusViewModelModalState.HiddenModalState)
-    }
-    val modalTransitionDialogHelper = ModalTransitionDialogHelper()
-    val navHostHelper = NimbusNavHostHelper()
 
-    if (nimbusViewModelModalState is NimbusViewModelModalState.OnShowModalModalState) {
-        val showModalState =
-            (nimbusViewModelModalState as? NimbusViewModelModalState.OnShowModalModalState)
         ModalTransitionDialog(
-            modalTransitionDialogHelper = modalTransitionDialogHelper,
-            onDismissRequest = {
-                nimbusViewModel.setModalHiddenState()
-            },
-            onCanDismissRequest = {
-                //Can dismiss the modal if we cannot pop more pages from navigation host
-                !navHostHelper.pop()
-            }
+            onDismissRequest = onDismiss,
         ) {
             NimbusNavHost(
-                modalParentHelper = modalTransitionDialogHelper,
-                nimbusNavHostHelper = navHostHelper,
-                viewRequest = showModalState?.viewRequest,
-                modifier = Modifier
-                    .fillMaxSize()
-                    .padding(16.dp)
-                    .background(Color.White)
-                    .padding(16.dp),
+                modalParentHelper = it,
+                viewRequest = viewRequest,
+                modifier = modifier
             )
         }
-    } else if (nimbusViewModelModalState is NimbusViewModelModalState.OnHideModalState) {
-        modalParentHelper.triggerAnimatedClose()
-    }
 
-    CollectFlow(nimbusViewModel.nimbusViewModelModalState) {
-        if (it != nimbusViewModelModalState)
-            nimbusViewModelModalState = it
-    }
 }

compose/src/main/java/br/zup/com/nimbus/compose/internal/NimbusNavHost.kt

@@ -1,6 +1,10 @@
 package br.zup.com.nimbus.compose.internal
 
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.navigation.NavHostController
@@ -13,8 +17,11 @@ import br.zup.com.nimbus.compose.Nimbus
 import br.zup.com.nimbus.compose.NimbusTheme.nimbus
 import br.zup.com.nimbus.compose.ProvideNavigatorState
 import br.zup.com.nimbus.compose.SHOW_VIEW_DESTINATION
-import br.zup.com.nimbus.compose.VIEW_JSON_DESCRIPTION
+import br.zup.com.nimbus.compose.JSON
+import br.zup.com.nimbus.compose.NimbusTheme
 import br.zup.com.nimbus.compose.VIEW_URL
+import br.zup.com.nimbus.compose.model.NimbusPageState
+import br.zup.com.nimbus.compose.model.Page
 import com.zup.nimbus.core.network.ViewRequest
 import java.util.UUID
 
@@ -41,6 +48,9 @@ internal fun NimbusNavHost(
         navigationState.handleNavigation(navController)
     }
 
+    val nimbusViewModelModalState: NimbusViewModelModalState by
+    nimbusViewModel.nimbusViewModelModalState.collectAsState()
+
     NimbusDisposableEffect(
         onCreate = {
             initNavHost(nimbusViewModel, viewRequest, json)
@@ -57,19 +67,29 @@ internal fun NimbusNavHost(
                 route = SHOW_VIEW_DESTINATION,
                 arguments = listOf(navArgument(VIEW_URL) {
                     type = NavType.StringType
-                    defaultValue = viewRequest?.url ?: VIEW_JSON_DESCRIPTION
+                    defaultValue = viewRequest?.url ?: JSON
                 })
             ) { backStackEntry ->
-                nimbusViewModel.getPageBy(
+                NimbusBackHandler(onDismiss =
+                {
+                    modalParentHelper.triggerAnimatedClose()
+                })
+
+                nimbusViewModelModalState.HandleModalState(
+                    onDismiss = {
+                        nimbusViewModel.setModalHiddenState()
+                    },
+                    onHideModal = {
+                        modalParentHelper.triggerAnimatedClose()
+                    }
+                )
+
+                val page = nimbusViewModel.getPageBy(
                     backStackEntry.getPageUrl()
-                )?.let { page ->
-                    NimbusBackHandler()
-                    page.Compose()
-                    NimbusModalView(
-                        nimbusViewModel = nimbusViewModel,
-                        modalParentHelper = modalParentHelper
-                    )
-                }
+                )
+
+                val pageRemember by remember(page?.id) { mutableStateOf(page) }
+                pageRemember?.Compose()
             }
         }
     }
@@ -89,7 +109,7 @@ private fun configureNavHostHelper(
 private fun initNavHost(
     nimbusViewModel: NimbusViewModel,
     viewRequest: ViewRequest?,
-    json: String
+    json: String,
 ) {
 
     if (viewRequest != null)
@@ -102,12 +122,12 @@ private fun initNavHost(
 /**
  * This helper can be used to control some behaviour from outside the NimbusNavHost composable
  */
-internal class NimbusNavHostHelper {
+class NimbusNavHostHelper {
 
-     var nimbusNavHostExecutor: NimbusNavHostExecutor? = null
-     fun isFirstScreen(): Boolean  = nimbusNavHostExecutor?.isFirstScreen() ?: false
+    var nimbusNavHostExecutor: NimbusNavHostExecutor? = null
+    fun isFirstScreen(): Boolean = nimbusNavHostExecutor?.isFirstScreen() ?: false
 
-     fun pop(): Boolean = nimbusNavHostExecutor?.pop() ?: false
+    fun pop(): Boolean = nimbusNavHostExecutor?.pop() ?: false
 
     interface NimbusNavHostExecutor {
         fun isFirstScreen(): Boolean