Basic Room integration

app/build.gradle.kts

@@ -2,6 +2,7 @@ plugins {
     alias(libs.plugins.android.application)
     alias(libs.plugins.kotlin.android)
     alias(libs.plugins.kotlin.compose)
+    id("com.google.devtools.ksp")
 }
 
 android {
@@ -40,6 +41,12 @@ android {
 }
 
 dependencies {
+    implementation(libs.androidx.room.common.jvm)
+    implementation(libs.androidx.room.runtime.android)
+    implementation(libs.androidx.lifecycle.viewmodel.compose.android)
+    val room_version = "2.7.2"
+
+    ksp("androidx.room:room-compiler:$room_version")
 
     implementation(libs.androidx.core.ktx)
     implementation(libs.androidx.lifecycle.runtime.ktx)

app/src/main/java/com/mirenkov/ktheightmap/MainActivity.kt

@@ -1,5 +1,6 @@
 package com.mirenkov.ktheightmap
 
+import android.app.Application
 import android.os.Bundle
 import android.util.Log
 import androidx.activity.ComponentActivity
@@ -20,31 +21,58 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.tooling.preview.Preview
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewmodel.compose.LocalViewModelStoreOwner
+import androidx.lifecycle.viewmodel.compose.viewModel
 import com.mirenkov.ktheightmap.ui.theme.KtHeightMapTheme
 
 const val TAG = "KtHeightMap"
 const val TILE_SIZE: Float = 256F
 
+class TileViewModelFactory(val application: Application):
+    ViewModelProvider.Factory {
+    override fun <T : ViewModel> create(modelClass: Class<T>): T {
+        @Suppress("UNCHECKED_CAST")
+        return TileViewModel(application) as T
+    }
+}
+
 class MainActivity : ComponentActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         enableEdgeToEdge()
         setContent {
-            KtHeightMapTheme {
-                Surface {
-                    Scaffold(
-                        modifier = Modifier.fillMaxSize()
-                            .safeDrawingPadding(),
-                        floatingActionButton = { ToolButton() }
-                    ) { innerPadding ->
-                        MapCanvas(
-                            gridColor = colorScheme.primary,
-                            backColor = colorScheme.background,
-                            modifier = Modifier.padding(innerPadding),
-                        )
-                    }
-                }
+            val owner = LocalViewModelStoreOwner.current
+
+            owner?.let {
+                val viewModel: TileViewModel = viewModel(
+                    it,
+                    "TileViewModel",
+                    TileViewModelFactory(LocalContext.current.applicationContext as Application)
+                )
+                Main(viewModel)
+            }
+        }
+    }
+}
+
+@Composable
+fun Main(vm: TileViewModel = viewModel()) {
+    KtHeightMapTheme {
+        Surface {
+            Scaffold(
+                modifier = Modifier.fillMaxSize()
+                    .safeDrawingPadding(),
+                floatingActionButton = { ToolButton() }
+            ) { innerPadding ->
+                MapCanvas(
+                    gridColor = colorScheme.primary,
+                    backColor = colorScheme.background,
+                    modifier = Modifier.padding(innerPadding),
+                )
             }
         }
     }

app/src/main/java/com/mirenkov/ktheightmap/Tile.kt

@@ -0,0 +1,30 @@
+package com.mirenkov.ktheightmap
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+
+@Entity(tableName = "tiles", primaryKeys = [ "x", "y", "level" ])
+class Tile {
+    @ColumnInfo(name = "x")
+    var x: Int = 0
+
+    @ColumnInfo(name = "y")
+    var y: Int = 0
+
+    @ColumnInfo(name = "level")
+    var level: Int = 0
+
+    @ColumnInfo(name = "data")
+    var base64: String? = null
+
+
+
+    constructor() {}
+
+    constructor(x: Int, y: Int, level: Int) {
+        this.x = x
+        this.y = y
+        this.level = level
+    }
+}

app/src/main/java/com/mirenkov/ktheightmap/TileDB.kt

@@ -0,0 +1,28 @@
+package com.mirenkov.ktheightmap
+
+import android.content.Context
+import androidx.room.Database
+import androidx.room.Room
+import androidx.room.RoomDatabase
+
+@Database(entities = [Tile::class], version = 1)
+abstract class TileDB: RoomDatabase() {
+    abstract fun tileDao(): TileDao
+
+    companion object {
+        private var INSTANCE: TileDB? = null
+        fun getInstance(context: Context): TileDB {
+            synchronized(this) {
+                var instance = INSTANCE
+                if (instance == null) {
+                    instance = Room.databaseBuilder(context.applicationContext,
+                        TileDB::class.java,
+                        "tiledb"
+                    ).fallbackToDestructiveMigration(true).build()
+                    INSTANCE = instance
+                }
+                return instance
+            }
+        }
+    }
+}

app/src/main/java/com/mirenkov/ktheightmap/TileDao.kt

@@ -0,0 +1,17 @@
+package com.mirenkov.ktheightmap
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.Query
+
+@Dao
+interface TileDao {
+    @Query("select * from tiles where x = :x and y = :y and level = :level")
+    fun getTile(x: Int, y: Int, level: Int): Tile?
+
+    @Insert
+    fun pushTile(tile: Tile)
+
+    @Query("delete from tiles")
+    fun clearTiles()
+}

app/src/main/java/com/mirenkov/ktheightmap/TileRepository.kt

@@ -0,0 +1,20 @@
+package com.mirenkov.ktheightmap
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+
+class TileRepository(private val tileDao: TileDao) {
+    private val coroutineScope = CoroutineScope(Dispatchers.Main)
+
+    fun pushTile(tile: Tile) {
+        tileDao.pushTile(tile)
+    }
+
+    fun getTile(x: Int, y: Int, level: Int): Tile? {
+        return tileDao.getTile(x, y, level)
+    }
+
+    fun clearTiles() {
+        tileDao.clearTiles()
+    }
+}

app/src/main/java/com/mirenkov/ktheightmap/TileViewModel.kt

@@ -0,0 +1,15 @@
+package com.mirenkov.ktheightmap
+
+import android.app.Application
+import androidx.compose.runtime.mutableStateOf
+import androidx.lifecycle.ViewModel
+
+class TileViewModel(application: Application): ViewModel() {
+    private val repository: TileRepository
+
+    init {
+        val tileDb = TileDB.getInstance(application)
+        val tileDao = tileDb.tileDao()
+        repository = TileRepository(tileDao)
+    }
+}

build.gradle.kts

@@ -3,4 +3,5 @@ plugins {
     alias(libs.plugins.android.application) apply false
     alias(libs.plugins.kotlin.android) apply false
     alias(libs.plugins.kotlin.compose) apply false
+    id("com.google.devtools.ksp") version "2.0.21-1.0.27" apply false
 }

gradle/libs.versions.toml

@@ -8,6 +8,9 @@ espressoCore = "3.6.1"
 lifecycleRuntimeKtx = "2.9.2"
 activityCompose = "1.10.1"
 composeBom = "2024.09.00"
+roomCommonJvm = "2.7.2"
+roomRuntimeAndroid = "2.7.2"
+lifecycleViewmodelComposeAndroid = "2.9.2"
 
 [libraries]
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
@@ -24,6 +27,9 @@ androidx-ui-tooling-preview = { group = "androidx.compose.ui", name = "ui-toolin
 androidx-ui-test-manifest = { group = "androidx.compose.ui", name = "ui-test-manifest" }
 androidx-ui-test-junit4 = { group = "androidx.compose.ui", name = "ui-test-junit4" }
 androidx-material3 = { group = "androidx.compose.material3", name = "material3" }
+androidx-room-common-jvm = { group = "androidx.room", name = "room-common-jvm", version.ref = "roomCommonJvm" }
+androidx-room-runtime-android = { group = "androidx.room", name = "room-runtime-android", version.ref = "roomRuntimeAndroid" }
+androidx-lifecycle-viewmodel-compose-android = { group = "androidx.lifecycle", name = "lifecycle-viewmodel-compose-android", version.ref = "lifecycleViewmodelComposeAndroid" }
 
 [plugins]
 android-application = { id = "com.android.application", version.ref = "agp" }