Fix: Error build on demo

Author: Nguyễn Tuấn Việt

android/src/main/kotlin/dev/brewkits/native_workmanager/engine/FlutterEngineManager.kt

@@ -263,7 +263,7 @@ object FlutterEngineManager {
             val idleTime = System.currentTimeMillis() - lastUsedTimestamp
             if (idleTime >= ENGINE_IDLE_TIMEOUT_MS) {
                 Log.d(TAG, "Auto-disposing engine after ${idleTime}ms idle")
-                dispose()
+                disposalScope.launch { dispose() }
             }
         }
     }
@@ -274,8 +274,7 @@ object FlutterEngineManager {
      * This frees ~30-50MB of RAM but future tasks will be slower
      * (need to cold-start engine again).
      */
-    @Synchronized
-    fun dispose() {
+    suspend fun dispose() {
         Log.d(TAG, "Disposing Flutter engine")
 
         methodChannel?.setMethodCallHandler(null)

example/android/app/build.gradle.kts

@@ -1,6 +1,8 @@
 plugins {
     id("com.android.application")
     id("kotlin-android")
+    id("kotlin-kapt")
+    id("org.jetbrains.kotlin.plugin.serialization") version "1.9.22"
     // The Flutter Gradle Plugin must be applied after the Android and Kotlin Gradle plugins.
     id("dev.flutter.flutter-gradle-plugin")
 }
@@ -42,3 +44,8 @@ android {
 flutter {
     source = "../.."
 }
+
+dependencies {
+    // Kotlinx Serialization
+    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.6.0")
+}

example/android/app/src/main/kotlin/dev/brewkits/native_workmanager_example/MainActivity.kt

@@ -13,12 +13,29 @@ import io.flutter.embedding.engine.FlutterEngine
 import io.flutter.plugin.common.MethodChannel
 import java.io.RandomAccessFile
 
+import dev.brewkits.native_workmanager.SimpleAndroidWorkerFactory
+import dev.brewkits.kmpworkmanager.background.domain.AndroidWorker
+import dev.brewkits.kmpworkmanager.background.domain.AndroidWorkerFactory
+import dev.brewkits.native_workmanager_example.workers.ImageCompressWorker // Import the custom worker
+
 class MainActivity : FlutterActivity() {
     private val METRICS_CHANNEL = "dev.brewkits.native_workmanager.example/metrics"
 
     override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
         super.configureFlutterEngine(flutterEngine)
 
+        // Register custom workers BEFORE Flutter engine starts
+        SimpleAndroidWorkerFactory.setUserFactory(object : AndroidWorkerFactory {
+            override fun createWorker(workerClassName: String): AndroidWorker? {
+                return when (workerClassName) {
+                    "ImageCompressWorker" -> ImageCompressWorker()
+                    // Add more custom workers here
+                    else -> null
+                }
+            }
+        })
+
+
         MethodChannel(flutterEngine.dartExecutor.binaryMessenger, METRICS_CHANNEL).setMethodCallHandler { call, result ->
             when (call.method) {
                 "getMemoryMB" -> {

example/android/app/src/main/kotlin/dev/brewkits/native_workmanager_example/workers/ImageCompressWorker.kt

@@ -0,0 +1,47 @@
+package dev.brewkits.native_workmanager_example.workers
+
+import android.graphics.Bitmap
+import android.graphics.BitmapFactory
+import dev.brewkits.kmpworkmanager.background.domain.AndroidWorker
+import dev.brewkits.kmpworkmanager.background.domain.WorkerResult // Added import for WorkerResult
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.jsonObject
+import kotlinx.serialization.json.jsonPrimitive
+import java.io.File
+import java.io.FileOutputStream
+
+class ImageCompressWorker : AndroidWorker {
+    override suspend fun doWork(input: String?): WorkerResult { // Changed return type to WorkerResult
+        try {
+            // Parse JSON input
+            val json = Json.parseToJsonElement(input ?: "{}")
+            val config = json.jsonObject
+
+            val inputPath = config["inputPath"]?.jsonPrimitive?.content
+                ?: return WorkerResult.Failure("Input path or output path missing")
+            val outputPath = config["outputPath"]?.jsonPrimitive?.content
+                ?: return WorkerResult.Failure("Input path or output path missing")
+            val quality = config["quality"]?.jsonPrimitive?.content?.toIntOrNull()
+                ?: 85
+
+            // Load image
+            val bitmap = BitmapFactory.decodeFile(inputPath)
+                ?: return WorkerResult.Failure("Failed to load image from input path")
+
+            // Compress and save
+            val outputFile = File(outputPath)
+            outputFile.parentFile?.mkdirs()
+
+            FileOutputStream(outputFile).use { out ->
+                bitmap.compress(Bitmap.CompressFormat.JPEG, quality, out)
+            }
+
+            bitmap.recycle()
+            return WorkerResult.Success()
+
+        } catch (e: Exception) {
+            println("ImageCompressWorker error: ${e.message}")
+            return WorkerResult.Failure("Image compression failed: ${e.message}")
+        }
+    }
+}