Convert Gallery sample to Kotlin using a ViewModel and Flow.

build.gradle

@@ -19,6 +19,7 @@ buildscript {
         classpath 'com.guardsquare:proguard-gradle:7.1.0'
         classpath "se.bjurr.violations:violations-gradle-plugin:${VIOLATIONS_PLUGIN_VERSION}"
         classpath "androidx.benchmark:benchmark-gradle-plugin:${ANDROID_X_BENCHMARK_VERSION}"
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:${JETBRAINS_KOTLIN_VERSION}"
     }
 }
 

gradle.properties

@@ -59,6 +59,12 @@ ANDROID_X_TEST_RULES_VERSION=1.1.0
 ANDROID_X_TEST_RUNNER_VERSION=1.1.0
 ANDROID_X_TRACING_VERSION=1.0.0
 ANDROID_X_VECTOR_DRAWABLE_ANIMATED_VERSION=1.0.0
+ANDROID_X_CORE_KTX_VERSION=1.8.0
+ANDROID_X_LIFECYCLE_KTX_VERSION=2.4.1
+
+# org.jetbrains versions
+JETBRAINS_KOTLINX_COROUTINES_VERSION=1.6.3
+JETBRAINS_KOTLIN_VERSION=1.7.0
 
 ## Other dependency versions
 ANDROID_GRADLE_VERSION=7.2.1

samples/gallery/build.gradle

@@ -1,29 +1,46 @@
 apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
+apply plugin: 'kotlin-kapt'
+apply plugin: "org.jetbrains.kotlin.plugin.parcelize"
 
 dependencies {
     implementation project(':library')
     implementation(project(':integration:recyclerview')) {
         transitive = false
     }
-    implementation "androidx.recyclerview:recyclerview:${ANDROID_X_RECYCLERVIEW_VERSION}"
-    implementation "androidx.fragment:fragment:${ANDROID_X_FRAGMENT_VERSION}"
-    annotationProcessor project(':annotation:compiler')
+
+    implementation "androidx.recyclerview:recyclerview:$ANDROID_X_RECYCLERVIEW_VERSION"
+    implementation "androidx.fragment:fragment-ktx:$ANDROID_X_FRAGMENT_VERSION"
+    implementation "androidx.core:core-ktx:$ANDROID_X_CORE_KTX_VERSION"
+    implementation "androidx.lifecycle:lifecycle-livedata-ktx:$ANDROID_X_LIFECYCLE_KTX_VERSION"
+    implementation "androidx.lifecycle:lifecycle-runtime-ktx:$ANDROID_X_LIFECYCLE_KTX_VERSION"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:$JETBRAINS_KOTLINX_COROUTINES_VERSION"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:$JETBRAINS_KOTLINX_COROUTINES_VERSION"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$JETBRAINS_KOTLIN_VERSION"
+
+    kapt project(':annotation:compiler')
+}
+
+kotlin {
+    jvmToolchain {
+        languageVersion.set(JavaLanguageVersion.of(11))
+    }
 }
 
 android {
-    compileSdkVersion COMPILE_SDK_VERSION as int
+    compileSdkVersion 32
 
     defaultConfig {
         applicationId 'com.bumptech.glide.samples.gallery'
-        minSdkVersion MIN_SDK_VERSION as int
-        targetSdkVersion TARGET_SDK_VERSION as int
+        minSdkVersion 29
+        targetSdkVersion 32
         versionCode 1
         versionName '1.0'
     }
 
     compileOptions {
-        sourceCompatibility JavaVersion.VERSION_1_7
-        targetCompatibility JavaVersion.VERSION_1_7
+        sourceCompatibility JavaVersion.VERSION_11
+        targetCompatibility JavaVersion.VERSION_11
     }
 }
 

samples/gallery/src/main/AndroidManifest.xml

@@ -9,6 +9,7 @@
           android:icon="@android:drawable/sym_def_app_icon"
           android:allowBackup="false">
     <activity android:name=".MainActivity"
+              android:exported="true"
               android:label="@string/app_name">
       <intent-filter>
         <action android:name="android.intent.action.MAIN"/>

samples/gallery/src/main/java/com/bumptech/glide/samples/gallery/GalleryModule.kt

@@ -0,0 +1,8 @@
+package com.bumptech.glide.samples.gallery
+
+import com.bumptech.glide.annotation.GlideModule
+import com.bumptech.glide.module.AppGlideModule
+
+/** Ensures that Glide's generated API is created for the Gallery sample.  */
+@GlideModule
+class GalleryModule : AppGlideModule()

samples/gallery/src/main/java/com/bumptech/glide/samples/gallery/GalleryViewModel.kt

@@ -0,0 +1,25 @@
+package com.bumptech.glide.samples.gallery
+
+import android.app.Application
+import androidx.lifecycle.AndroidViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.launch
+
+class GalleryViewModel(application: Application) : AndroidViewModel(application) {
+  private val mediaStoreDataSource = MediaStoreDataSource(application)
+
+  private val _uiState: MutableStateFlow<List<MediaStoreData>> = MutableStateFlow(emptyList())
+  val mediaStoreData: StateFlow<List<MediaStoreData>> = _uiState
+
+  init {
+    viewModelScope.launch {
+      mediaStoreDataSource.loadMediaStoreData().flowOn(Dispatchers.IO).collect {
+        _uiState.value = it
+      }
+    }
+  }
+}

samples/gallery/src/main/java/com/bumptech/glide/samples/gallery/HorizontalGalleryFragment.kt

@@ -0,0 +1,50 @@
+package com.bumptech.glide.samples.gallery
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+import androidx.fragment.app.viewModels
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
+import androidx.recyclerview.widget.RecyclerView
+import androidx.recyclerview.widget.GridLayoutManager
+import com.bumptech.glide.integration.recyclerview.RecyclerViewPreloader
+import kotlinx.coroutines.launch
+
+/** Displays media store data in a recycler view.  */
+class HorizontalGalleryFragment : Fragment() {
+  private lateinit var adapter: RecyclerAdapter
+  private lateinit var recyclerView: RecyclerView
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    val galleryViewModel: GalleryViewModel by viewModels()
+    lifecycleScope.launch {
+      repeatOnLifecycle(Lifecycle.State.STARTED) {
+        galleryViewModel.mediaStoreData.collect { data ->
+          adapter.setData(data)
+        }
+      }
+    }
+  }
+
+  override fun onCreateView(
+    inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?,
+  ): View? {
+    val result = inflater.inflate(R.layout.recycler_view, container, false)
+    recyclerView = result.findViewById<View>(R.id.recycler_view) as RecyclerView
+    val layoutManager = GridLayoutManager(activity, 1)
+    layoutManager.orientation = RecyclerView.HORIZONTAL
+    recyclerView.layoutManager = layoutManager
+    recyclerView.setHasFixedSize(true)
+
+    val glideRequests = GlideApp.with(this)
+    adapter = RecyclerAdapter(requireContext(), glideRequests)
+    val preloader = RecyclerViewPreloader(glideRequests, adapter, adapter, 3)
+    recyclerView.addOnScrollListener(preloader)
+    recyclerView.adapter = adapter
+    return result
+  }
+}

samples/gallery/src/main/java/com/bumptech/glide/samples/gallery/MainActivity.kt

@@ -0,0 +1,61 @@
+package com.bumptech.glide.samples.gallery
+
+import android.Manifest
+import android.content.pm.PackageManager
+import android.os.Bundle
+import android.widget.Toast
+import androidx.core.app.ActivityCompat
+import androidx.core.content.ContextCompat
+import androidx.fragment.app.Fragment
+import androidx.fragment.app.FragmentActivity
+import com.bumptech.glide.MemoryCategory
+
+/** Displays a [HorizontalGalleryFragment].  */
+class MainActivity : FragmentActivity() {
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    setContentView(R.layout.main_activity)
+    GlideApp.get(this).setMemoryCategory(MemoryCategory.HIGH)
+    if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
+      != PackageManager.PERMISSION_GRANTED
+    ) {
+      requestStoragePermission()
+    } else {
+      replaceFragment()
+    }
+  }
+
+  private fun requestStoragePermission() {
+    ActivityCompat.requestPermissions(
+      this, arrayOf(Manifest.permission.READ_EXTERNAL_STORAGE), REQUEST_READ_STORAGE)
+  }
+
+  private fun replaceFragment() {
+    val fragment: Fragment = HorizontalGalleryFragment()
+    supportFragmentManager
+      .beginTransaction()
+      .replace(R.id.fragment_container, fragment)
+      .commit()
+  }
+
+  override fun onRequestPermissionsResult(
+    requestCode: Int, permissions: Array<String>, grantResults: IntArray,
+  ) {
+    super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+    when (requestCode) {
+      REQUEST_READ_STORAGE -> {
+        // If request is cancelled, the result arrays are empty.
+        if (grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
+          replaceFragment()
+        } else {
+          Toast.makeText(this, "Storage permission is required", Toast.LENGTH_LONG).show()
+          requestStoragePermission()
+        }
+      }
+    }
+  }
+
+  companion object {
+    private const val REQUEST_READ_STORAGE = 0
+  }
+}