How to Detect Language and Translate text in Android with Firebase ML Kit

Before You Begin

dependencies {
      // ...
      // Use this dependency to bundle the model with your app
      implementation 'com.google.mlkit:language-id:17.0.1'

      // Use this dependency to use the dynamically downloaded model in Google Play Services
      implementation 'com.google.android.gms:play-services-mlkit-language-id:16.0.0-beta2'
      
      // Use this dependency to use the translate text
      implementation 'com.google.mlkit:translate:16.1.2'
    }
 

  <application ...>
          ...
          <meta-data
              android:name="com.google.mlkit.vision.DEPENDENCIES"
              android:value="langid" />
          <!-- To use multiple models: android:value="langid,model2,model3" -->
      </application>
    

Identify Language

LanguageIdentification.getClient().identifyLanguage("Hello World!")
            .addOnSuccessListener { languageCode ->
                when (languageCode) {
                    "en"  -> { ... }
                    "und" ->  Log.i("TAG", "Language: $languageCode")
                    else  ->  Log.i("TAG", "Can't identify language.")
                }
            }

LanguageIdentification
        .getClient(LanguageIdentificationOptions.Builder()
                .setConfidenceThreshold(0.34f)
                .build())

Translate Text

val frenchModel = TranslateRemoteModel.Builder(TranslateLanguage.FRENCH).build()
val modelManager = RemoteModelManager.getInstance()
modelManager.download(frenchModel, DownloadConditions.Builder().build())

// Create an English-French translator:
val options = TranslatorOptions.Builder()
    .setSourceLanguage(TranslateLanguage.ENGLISH)
    .setTargetLanguage(TranslateLanguage.FRENCH)
    .build()
val englishFrenchTranslator = Translation.getClient(options)

var conditions = DownloadConditions.Builder()
    .requireWifi() // download models only by wifi
    .build()


englishFrenchTranslator.downloadModelIfNeeded(conditions)
    .addOnSuccessListener {
        // Model downloaded successfully. Okay to start translating.
        // (Set a flag, unhide the translation UI, etc.)
    }
    .addOnFailureListener { exception ->
        // Model couldn’t be downloaded or other internal error.
        // ...
    }

modelManager.getDownloadedModels(TranslateRemoteModel::class.java)
    .addOnSuccessListener { models ->
        // ...
    }
    .addOnFailureListener {
        // Error.
    }

modelManager.deleteDownloadedModel(frenchModel)

englishFrenchTranslator.translate(text)
    .addOnSuccessListener { translatedText ->
        // Translation successful.
    }
    .addOnFailureListener { exception ->
         // Error.
         // ...
    }

Conclusion