add DaggerAndroidWorker (demo inject to worker using dagger-android)

app/build.gradle

@@ -32,6 +32,7 @@ dependencies {
     // Dagger
     implementation "com.google.dagger:dagger-android:$dagger_version"
     kapt "com.google.dagger:dagger-compiler:$dagger_version"
+    kapt "com.google.dagger:dagger-android-processor:$dagger_version"
 
     // Work Manager
     implementation "androidx.work:work-runtime-ktx:2.3.4"

app/src/main/java/com/sample/daggerworkmanagersample/DI.kt

@@ -6,12 +6,15 @@ import dagger.Binds
 import dagger.Component
 import dagger.MapKey
 import dagger.Module
+import dagger.android.AndroidInjectionModule
 import dagger.android.AndroidInjector
 import dagger.multibindings.IntoMap
 import kotlin.reflect.KClass
 
 @Component(
     modules = [
+        AndroidInjectionModule::class,
+        DaggerAndroidWorker.Module::class,
         SampleAssistedInjectModule::class,
         WorkerBindingModule::class
     ]

app/src/main/java/com/sample/daggerworkmanagersample/DaggerAndroidWorker.kt

@@ -0,0 +1,42 @@
+package com.sample.daggerworkmanagersample
+
+import android.content.Context
+import android.util.Log
+import androidx.work.Worker
+import androidx.work.WorkerParameters
+import dagger.android.ContributesAndroidInjector
+import dagger.android.HasAndroidInjector
+import javax.inject.Inject
+
+
+object ContextInjection {
+    @JvmStatic
+    fun inject(to: Any, with: Context) {
+        (with.applicationContext as HasAndroidInjector).androidInjector().inject(to)
+    }
+}
+
+class DaggerAndroidWorker(
+    context: Context,
+    params: WorkerParameters
+) : Worker(context, params) {
+
+    @Inject
+    lateinit var foo: Foo
+
+    init {
+        ContextInjection.inject(to = this, with = context)
+    }
+
+    override fun doWork(): Result {
+        Log.d("DaggerAndroidWorker", "Injected foo: $foo")
+        return Result.success()
+    }
+
+
+    @dagger.Module
+    interface Module {
+        @ContributesAndroidInjector
+        fun worker(): DaggerAndroidWorker
+    }
+}

app/src/main/java/com/sample/daggerworkmanagersample/HelloWorldWorker.kt

@@ -2,10 +2,7 @@ package com.sample.daggerworkmanagersample
 
 import android.content.Context
 import android.util.Log
-import androidx.work.ListenableWorker
-import androidx.work.Worker
-import androidx.work.WorkerFactory
-import androidx.work.WorkerParameters
+import androidx.work.*
 import com.squareup.inject.assisted.Assisted
 import com.squareup.inject.assisted.AssistedInject
 import javax.inject.Inject
@@ -33,19 +30,25 @@ interface ChildWorkerFactory {
     fun create(appContext: Context, params: WorkerParameters): ListenableWorker
 }
 
+/**
+ * If there is no worker found, return null to use the default behaviour of [WorkManager]
+ * (create worker using refection)
+ *
+ * @see WorkerFactory.createWorkerWithDefaultFallback
+ */
 class SampleWorkerFactory @Inject constructor(
     private val workerFactories: Map<Class<out ListenableWorker>, @JvmSuppressWildcards Provider<ChildWorkerFactory>>
 ) : WorkerFactory() {
+
     override fun createWorker(
         appContext: Context,
         workerClassName: String,
         workerParameters: WorkerParameters
     ): ListenableWorker? {
-        val foundEntry =
-            workerFactories.entries.find { Class.forName(workerClassName).isAssignableFrom(it.key) }
-        val factoryProvider = foundEntry?.value
-            ?: throw IllegalArgumentException("unknown worker class name: $workerClassName")
-        return factoryProvider.get().create(appContext, workerParameters)
+        val foundEntry = workerFactories.entries
+            .find { Class.forName(workerClassName).isAssignableFrom(it.key) }
+            ?: return null
+        return foundEntry.value.get().create(appContext, workerParameters)
     }
 }
 

app/src/main/java/com/sample/daggerworkmanagersample/MainActivity.kt

@@ -16,5 +16,10 @@ class MainActivity : Activity() {
                 OneTimeWorkRequestBuilder<HelloWorldWorker>().build()
             )
         }
+        findViewById<Button>(R.id.hello_button2).setOnClickListener {
+            WorkManager.getInstance(this).enqueue(
+                OneTimeWorkRequestBuilder<DaggerAndroidWorker>().build()
+            )
+        }
     }
 }

app/src/main/java/com/sample/daggerworkmanagersample/SampleApplication.kt

@@ -2,8 +2,15 @@ package com.sample.daggerworkmanagersample
 
 import android.app.Application
 import androidx.work.Configuration
+import dagger.android.AndroidInjector
+import dagger.android.DispatchingAndroidInjector
+import dagger.android.HasAndroidInjector
+import javax.inject.Inject
 
-class SampleApplication : Application(), Configuration.Provider {
+class SampleApplication : Application(), Configuration.Provider, HasAndroidInjector {
+
+    @Inject
+    lateinit var androidInjector: DispatchingAndroidInjector<Any>
 
     private lateinit var sampleComponent: SampleComponent
 
@@ -17,4 +24,8 @@ class SampleApplication : Application(), Configuration.Provider {
         val factory: SampleWorkerFactory = sampleComponent.factory()
         return Configuration.Builder().setWorkerFactory(factory).build()
     }
+
+    override fun androidInjector(): AndroidInjector<Any> {
+        return androidInjector
+    }
 }

app/src/main/res/layout/activity_main.xml

@@ -14,4 +14,12 @@
         android:layout_marginTop="64dp"
         android:text="Enqueue HelloWorldWorker" />
 
+    <Button
+        android:id="@+id/hello_button2"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center_horizontal"
+        android:layout_marginTop="64dp"
+        android:text="Enqueue DaggerAndroidWorker" />
+
 </LinearLayout>