Refactor ViewModel and introduce basic navigation

This commit refactors the ViewModel structure and introduces basic navigation capabilities using Jetpack Navigation Compose.

Key changes:
- Renamed `MainViewModel.kt` to `DiffCheckerViewModel.kt` and moved it to the `presentation.viewmodel` package.
- `DiffCheckerViewModel` now takes a `NavigationRouter` in its constructor.
- Introduced a `NavigationRouter` interface and a `NavControllerRouter` implementation for managing navigation actions.
- Added `Screen.kt` to define navigation routes for `DiffChecker` and a new `DiffViewer` screen.
- Created a placeholder `DiffViewerScreen.kt`.
- Updated `MainActivity.kt` to set up `NavHost` with routes for `DiffCheckerScreen` and `DiffViewerScreen`.
- `DiffCheckerScreen.kt` now uses `DiffCheckerViewModel`.
- Added `navigation-compose` dependency to `build.gradle.kts` and `libs.versions.toml`.

Author: JahidHasanCO

app/build.gradle.kts

@@ -68,6 +68,9 @@ dependencies {
     implementation(libs.androidx.material3)
     implementation(libs.androidx.material.icons.core)
     implementation(libs.androidx.material.icons.extended)
+    implementation(libs.navigation.compose)
+
+
     androidTestImplementation(libs.androidx.espresso.core)
     androidTestImplementation(platform(libs.androidx.compose.bom))
     debugImplementation(libs.androidx.ui.tooling)

app/src/main/java/dev/jahidhasanco/diffly/navigation/NavControllerRouter.kt

@@ -0,0 +1,18 @@
+package dev.jahidhasanco.diffly.navigation
+
+import androidx.navigation.NavController
+
+class NavControllerRouter(private val navController: NavController) : NavigationRouter {
+
+    override fun navigateToDiffChecker() {
+        navController.navigate(Screen.DiffChecker.route)
+    }
+
+    override fun navigateToDiffViewer() {
+        navController.navigate(Screen.DiffViewer.route)
+    }
+
+    override fun goBack() {
+        navController.popBackStack()
+    }
+}

app/src/main/java/dev/jahidhasanco/diffly/navigation/NavigationRouter.kt

@@ -0,0 +1,7 @@
+package dev.jahidhasanco.diffly.navigation
+
+interface NavigationRouter {
+    fun navigateToDiffChecker()
+    fun navigateToDiffViewer()
+    fun goBack()
+}

app/src/main/java/dev/jahidhasanco/diffly/navigation/NavigationRoutes.kt

@@ -0,0 +1,6 @@
+package dev.jahidhasanco.diffly.navigation
+
+sealed class Screen(val route: String) {
+    object DiffChecker : Screen("diff_checker")
+    object DiffViewer : Screen("diff_viewer")
+}

app/src/main/java/dev/jahidhasanco/diffly/presentation/MainActivity.kt

@@ -4,18 +4,22 @@ import android.app.Activity
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
+import androidx.compose.runtime.Composable
 import androidx.compose.runtime.SideEffect
 import androidx.compose.ui.platform.LocalView
 import androidx.core.view.WindowCompat
 import androidx.core.view.WindowInsetsControllerCompat
+import androidx.navigation.compose.NavHost
+import androidx.navigation.compose.composable
+import androidx.navigation.compose.rememberNavController
 import dev.jahidhasanco.diffly.di.AppModule
+import dev.jahidhasanco.diffly.navigation.NavControllerRouter
+import dev.jahidhasanco.diffly.navigation.Screen
 import dev.jahidhasanco.diffly.presentation.screen.DiffCheckerScreen
+import dev.jahidhasanco.diffly.presentation.screen.DiffViewerScreen
+import dev.jahidhasanco.diffly.presentation.viewmodel.DiffCheckerViewModel
 
 class MainActivity : ComponentActivity() {
-    private val viewModel by lazy {
-        MainViewModel(AppModule.calculateDiffUseCase)
-    }
-
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContent {
@@ -24,11 +28,34 @@ class MainActivity : ComponentActivity() {
                 SideEffect {
                     val window = (view.context as Activity).window
                     WindowCompat.setDecorFitsSystemWindows(window, true)
-                    WindowInsetsControllerCompat(window, view).isAppearanceLightStatusBars = true
+                    WindowInsetsControllerCompat(
+                        window, view
+                    ).isAppearanceLightStatusBars = true
                 }
             }
+            AppNavHost()
+        }
+    }
+}
+
+@Composable
+fun AppNavHost() {
+    val navController = rememberNavController()
+    val router = NavControllerRouter(navController)
+
+    NavHost(
+        navController = navController,
+        startDestination = Screen.DiffChecker.route
+    ) {
+        composable(Screen.DiffChecker.route) {
+            val viewModel by lazy {
+                DiffCheckerViewModel(AppModule.calculateDiffUseCase, router)
+            }
             DiffCheckerScreen(viewModel)
         }
+        composable(Screen.DiffViewer.route) {
+            DiffViewerScreen()
+        }
     }
 }
 

app/src/main/java/dev/jahidhasanco/diffly/presentation/screen/DiffCheckerScreen.kt

@@ -49,16 +49,16 @@ import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import dev.jahidhasanco.diffly.domain.model.DiffViewType
-import dev.jahidhasanco.diffly.presentation.MainViewModel
 import dev.jahidhasanco.diffly.presentation.component.ColumCharDiffText
 import dev.jahidhasanco.diffly.presentation.component.TwoSideCharDiffText
 import dev.jahidhasanco.diffly.presentation.component.UnifiedCharDiffText
 import dev.jahidhasanco.diffly.presentation.theme.background
 import dev.jahidhasanco.diffly.presentation.theme.primary
+import dev.jahidhasanco.diffly.presentation.viewmodel.DiffCheckerViewModel
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
-fun DiffCheckerScreen(viewModel: MainViewModel) {
+fun DiffCheckerScreen(viewModel: DiffCheckerViewModel) {
     var oldText by remember { mutableStateOf("") }
     var newText by remember { mutableStateOf("") }
     val diffResult by viewModel.diffResult.collectAsState()

app/src/main/java/dev/jahidhasanco/diffly/presentation/screen/DiffViewerScreen.kt

@@ -0,0 +1,7 @@
+package dev.jahidhasanco.diffly.presentation.screen
+
+import androidx.compose.runtime.Composable
+
+@Composable
+fun DiffViewerScreen() {
+}

…nco/diffly/presentation/MainViewModel.kt …tation/viewmodel/DiffCheckerViewModel.ktapp/src/main/java/dev/jahidhasanco/diffly/presentation/MainViewModel.kt renamed to app/src/main/java/dev/jahidhasanco/diffly/presentation/viewmodel/DiffCheckerViewModel.kt app/src/main/java/dev/jahidhasanco/diffly/presentation/MainViewModel.kt renamed to app/src/main/java/dev/jahidhasanco/diffly/presentation/viewmodel/DiffCheckerViewModel.kt

@@ -1,16 +1,18 @@
-package dev.jahidhasanco.diffly.presentation
+package dev.jahidhasanco.diffly.presentation.viewmodel
 
 import android.util.Log
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import dev.jahidhasanco.diffly.domain.model.DiffEntry
 import dev.jahidhasanco.diffly.domain.usecase.CalculateDiffUseCase
+import dev.jahidhasanco.diffly.navigation.NavigationRouter
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.launch
 
-class MainViewModel(
-    private val calculateDiffUseCase: CalculateDiffUseCase
+class DiffCheckerViewModel(
+    private val calculateDiffUseCase: CalculateDiffUseCase,
+    private val router: NavigationRouter
 ) : ViewModel() {
 
     private val _diffResult = MutableStateFlow<List<DiffEntry>>(emptyList())
@@ -23,4 +25,4 @@ class MainViewModel(
             _diffResult.value = result
         }
     }
-}
+}

gradle/libs.versions.toml

@@ -9,6 +9,8 @@ composeBom = "2024.09.00"
 materialIconsCore = "1.7.8"
 materialIconsExtended = "1.7.8"
 material = "1.8.3"
+navigation = "2.7.3"
+
 
 [libraries]
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
@@ -25,7 +27,7 @@ androidx-ui-tooling-preview = { group = "androidx.compose.ui", name = "ui-toolin
 androidx-ui-test-manifest = { group = "androidx.compose.ui", name = "ui-test-manifest" }
 androidx-material3 = { group = "androidx.compose.material3", name = "material3" }
 androidx-material = { group = "androidx.compose.material", name = "material", version.ref = "material" }
-
+navigation-compose = { module = "androidx.navigation:navigation-compose", version.ref = "navigation" }
 
 
 [plugins]