Kotlin is a modern programming language that combines the advantages of Java and adds many new features, such as support for functional programming, null safety, and more. Kotlin has become a very popular programming language in Android development. In this article, we will write a simple speech recognition program for Android using Kotlin.

Step 1: Create a new project

First, create a new Kotlin project in Android Studio. In order to implement the speech recognition function, we need to add some libraries to the project. Open the app-level build.gradle file and add the following code in the dependencies section:

implementation 'com.google.android.gms:play-services-speech:16.0.0'

This will add the Google Speech Recognition API to the project.

Step 2: Create a UI

Next, we need to create a simple user interface so the user can click a button to start recording. Add the following code to the activity_main.xml file:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:padding="16dp"
     >
     <Button
         android:id="@+id/record_button"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:text="recording"
         android:onClick="startRecording"
         android:layout_marginTop="16dp"
         />
     <TextView
         android:id="@+id/result_textview"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_below="@id/record_button"
         android:layout_marginTop="16dp"
         />
</RelativeLayout>

In this layout we add a button and a textbox. When the user clicks the button, we will start the speech recognizer and display the result in a textbox.

Step 3: Implement Speech Recognition

Now we need to implement speech recognition in the MainActivity.kt file. First, we need to import the relevant classes:

import android.content.Intent
import android.speech.RecognizerIntent
import android.widget.TextView
import java.util.*

Next, we need to add a member variable in the MainActivity class to store the reference of the text box:

private lateinit var resultTextView: TextView

Then, get a reference to the textbox in the onCreate method:

resultTextView = findViewById(R.id.result_textview)

Next, we need to add a startRecording method to start the speech recognizer. In this method, we will use the Intent to start the speech recognizer, and specify the language as Locale.getDefault(). This will make the speech recognizer use the device's current language setting.

fun startRecording(view: View) {
     val intent = Intent(RecognizerIntent. ACTION_RECOGNIZE_SPEECH)
     intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,             RecognizerIntent.LANGUAGE_MODEL_FREE_FORM)
     intent. putExtra(RecognizerIntent. EXTRA_LANGUAGE, Locale. getDefault())
     startActivityForResult(intent, 1)
}

In this method, we also call the startActivityForResult method, which will allow us to process the results returned by the speech recognizer.

Next, we need to implement the onActivityResult method to handle the result of the speech recognizer. In this method we will check if the resultCode is equal to RESULT_OK and if the requestCode is equal to 1. If the condition is true, we will take the result returned by the speech recognizer and display it in the textbox.

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
     super.onActivityResult(requestCode, resultCode, data)
     if (requestCode == 1 && resultCode == RESULT_OK) {
         val results = data?.getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS)
         val text = results?.get(0)
         resultTextView. text = text
     }
}

Now, we have completed the steps of writing a simple speech recognition program for Android using Kotlin. After this, you can run the program and test it out.

Summarize

In this article, we wrote a simple speech recognition program for Android using Kotlin. We learned how to add the Google Speech Recognition API to the project, and added a button and a text field to the UI. We then implemented a startRecording method to start the speech recognizer and an onActivityResult method to process the result of the speech recognizer. Through the guidance of this article, you can learn how to use Kotlin to write a simple Android speech recognition program, and further expand on this basis.

Author： yuday Posts：Use Kotlin to write Android speech recognition program