Update Translate showcase app to use custom executors

android/translate-showcase/app/build.gradle

@@ -68,8 +68,8 @@ dependencies {
     implementation "androidx.camera:camera-view:1.0.0-alpha12"
 
     // Add ML Kit dependencies
-    implementation 'com.google.android.gms:play-services-mlkit-text-recognition:16.0.0'
-    implementation 'com.google.mlkit:language-id:16.0.0'
-    implementation 'com.google.mlkit:translate:16.0.0'
+    implementation 'com.google.android.gms:play-services-mlkit-text-recognition:16.1.0'
+    implementation 'com.google.mlkit:language-id:16.1.0'
+    implementation 'com.google.mlkit:translate:16.1.0'
 }
 apply plugin: 'com.google.android.gms.strict-version-matcher-plugin'

android/translate-showcase/app/src/main/java/com/google/mlkit/showcase/translate/analyzer/TextAnalyzer.kt

@@ -31,7 +31,8 @@ import com.google.mlkit.showcase.translate.util.ImageUtils
 import com.google.mlkit.vision.common.InputImage
 import com.google.mlkit.vision.text.Text
 import com.google.mlkit.vision.text.TextRecognition
-import java.lang.Exception
+import com.google.mlkit.vision.text.TextRecognizerOptions
+import java.util.concurrent.Executor
 
 /**
  * Analyzes the frames passed in from the camera and returns any detected text within the requested
@@ -40,10 +41,12 @@ import java.lang.Exception
 class TextAnalyzer(
     private val context: Context,
     lifecycle: Lifecycle,
+    executor: Executor,
     private val result: MutableLiveData<String>,
     private val imageCropPercentages: MutableLiveData<Pair<Int, Int>>
 ) : ImageAnalysis.Analyzer {
-    private val detector = TextRecognition.getClient()
+    private val detector =
+        TextRecognition.getClient(TextRecognizerOptions.Builder().setExecutor(executor).build())
 
     init {
         lifecycle.addObserver(detector)

android/translate-showcase/app/src/main/java/com/google/mlkit/showcase/translate/main/MainFragment.kt

@@ -44,7 +44,6 @@ import com.google.mlkit.showcase.translate.analyzer.TextAnalyzer
 import com.google.mlkit.showcase.translate.util.Language
 import com.google.mlkit.showcase.translate.util.ScopedExecutor
 import kotlinx.android.synthetic.main.main_fragment.*
-import java.util.concurrent.Executor
 import java.util.concurrent.ExecutorService
 import java.util.concurrent.Executors
 import kotlin.math.abs
@@ -108,9 +107,11 @@ class MainFragment : Fragment() {
         viewFinder = container.findViewById(R.id.viewfinder)
 
         // Initialize our background executor
-        cameraExecutor = Executors.newSingleThreadExecutor()
+        cameraExecutor = Executors.newCachedThreadPool()
         scopedExecutor = ScopedExecutor(cameraExecutor)
 
+        viewModel.executor = cameraExecutor
+
         // Request camera permissions
         if (allPermissionsGranted()) {
             // Wait for the views to be properly laid out
@@ -178,8 +179,7 @@ class MainFragment : Fragment() {
                 ) {
                 }
 
-                override fun surfaceDestroyed(holder: SurfaceHolder?) {
-                }
+                override fun surfaceDestroyed(holder: SurfaceHolder?) {}
 
                 override fun surfaceCreated(holder: SurfaceHolder?) {
                     holder?.let {
@@ -239,6 +239,7 @@ class MainFragment : Fragment() {
                     scopedExecutor, TextAnalyzer(
                         requireContext(),
                         lifecycle,
+                        cameraExecutor,
                         viewModel.sourceText,
                         viewModel.imageCropPercentages
                     )

android/translate-showcase/app/src/main/java/com/google/mlkit/showcase/translate/main/MainViewModel.kt

@@ -23,30 +23,38 @@ import android.util.LruCache
 import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.MediatorLiveData
 import androidx.lifecycle.MutableLiveData
-import androidx.lifecycle.Transformations
 import com.google.android.gms.tasks.OnCompleteListener
 import com.google.android.gms.tasks.Task
 import com.google.android.gms.tasks.Tasks
-import com.google.mlkit.showcase.translate.util.Language
-import com.google.mlkit.showcase.translate.util.ResultOrError
-import com.google.mlkit.showcase.translate.util.SmoothedMutableLiveData
 import com.google.mlkit.nl.languageid.LanguageIdentification
+import com.google.mlkit.nl.languageid.LanguageIdentificationOptions
 import com.google.mlkit.nl.translate.TranslateLanguage
 import com.google.mlkit.nl.translate.Translation
 import com.google.mlkit.nl.translate.Translator
 import com.google.mlkit.nl.translate.TranslatorOptions
 import com.google.mlkit.showcase.translate.main.MainFragment.Companion.DESIRED_HEIGHT_CROP_PERCENT
 import com.google.mlkit.showcase.translate.main.MainFragment.Companion.DESIRED_WIDTH_CROP_PERCENT
+import com.google.mlkit.showcase.translate.util.Language
+import com.google.mlkit.showcase.translate.util.ResultOrError
+import com.google.mlkit.showcase.translate.util.SmoothedMutableLiveData
+import java.util.concurrent.Executor
 
 class MainViewModel(application: Application) : AndroidViewModel(application) {
-    private val languageIdentification = LanguageIdentification.getClient()
     override fun onCleared() {
         languageIdentification.close()
         translators.evictAll()
     }
 
+    lateinit var executor: Executor
+    private val languageIdentification by lazy {
+        LanguageIdentification.getClient(
+            LanguageIdentificationOptions.Builder().setExecutor(executor).build()
+        )
+    }
+
     val targetLang = MutableLiveData<Language>()
     val sourceText = SmoothedMutableLiveData<String>(SMOOTHING_DURATION)
+
     // We set desired crop percentages to avoid having the analyze the whole image from the live
     // camera feed. However, we are not guaranteed what aspect ratio we will get from the camera, so
     // we use the first frame we get back from the camera to update these crop percentages based on
@@ -75,34 +83,23 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
             }
         }
 
-    val sourceLang = Transformations.switchMap(sourceText) { text ->
-        val result = MutableLiveData<Language>()
-        languageIdentification.identifyLanguage(text)
-            .addOnSuccessListener {
-                if (it != "und")
-                    result.value = Language(it)
-            }
-        result
-    }
+    val sourceLang = MediatorLiveData<Language>()
 
     private fun translate(): Task<String> {
-        val text = sourceText.value
-        val source = sourceLang.value
-        val target = targetLang.value
         if (modelDownloading.value != false || translating.value != false) {
             return Tasks.forCanceled()
         }
-        if (source == null || target == null || text == null || text.isEmpty()) {
-            return Tasks.forResult("")
-        }
-        val sourceLangCode = TranslateLanguage.fromLanguageTag(source.code)
-        val targetLangCode = TranslateLanguage.fromLanguageTag(target.code)
-        if (sourceLangCode == null || targetLangCode == null) {
-            return Tasks.forCanceled()
-        }
+        val text = sourceText.value ?: return Tasks.forResult("")
+        val source = sourceLang.value ?: return Tasks.forResult("")
+        val target = targetLang.value ?: return Tasks.forResult("")
+        val sourceLangCode =
+            TranslateLanguage.fromLanguageTag(source.code) ?: return Tasks.forCanceled()
+        val targetLangCode =
+            TranslateLanguage.fromLanguageTag(target.code) ?: return Tasks.forCanceled()
         val options = TranslatorOptions.Builder()
             .setSourceLanguage(sourceLangCode)
             .setTargetLanguage(targetLangCode)
+            .setExecutor(executor)
             .build()
         val translator = translators[options]
         modelDownloading.setValue(true)
@@ -127,6 +124,15 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
     init {
         modelDownloading.setValue(false)
         translating.value = false
+
+        sourceLang.addSource(sourceText) { text ->
+            languageIdentification.identifyLanguage(text)
+                .addOnSuccessListener {
+                    if (it != "und")
+                        sourceLang.value = Language(it)
+                }
+        }
+
         // Create a translation result or error object.
         val processTranslation =
             OnCompleteListener<String> { task ->

android/translate-showcase/settings.gradle

@@ -16,4 +16,4 @@
  */
 
 include ':app'
-rootProject.name='ML Kit Translate Codelab'
+rootProject.name='ML Kit Translate Showcase'