An IntentService is a subclass of Service in Android that is used to handle asynchronous requests (expressed as “Intents”) on demand. It runs in the background and stops itself once it has processed all the intents that were sent to it.
An IntentService in Java and Kotlin:
Kotlin
class MyIntentService : IntentService("MyIntentService") { override fun onHandleIntent(intent: Intent?) { // Perform some background task here }} |
Java
public class MyIntentService extends IntentService { public MyIntentService() { super("MyIntentService"); } @Override protected void onHandleIntent(Intent intent) { // Perform some background task here }} |
You can start an IntentService by creating an Intent object and passing it to the startService() method. The Intent should contain any data that you want to pass to the service.
Kotlin
val intent = Intent(this, MyIntentService::class.java)intent.putExtra("data", "my data")startService(intent) |
Java
Intent intent = new Intent(this, MyIntentService.class);intent.putExtra("data", "my data");startService(intent); |
IntentService runs on a single background thread, so if you have multiple requests, they will be queued and processed one after the other, it could also stop itself after processing all intents. For better performance and to avoid ANR (Application not responding), you should offload long-running or heavy tasks to a separate thread within the onHandleIntent() method. An IntentService is a good choice when you have a small number of tasks that need to be done in the background, and you don’t need to run them concurrently.
Step-by-Step Implementation
Step 1: Create a New Project in Android Studio
To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. The code for that has been given in both Java and Kotlin Programming Language for Android.
Step 2: Declaring IntentService in the AndroidManifest.xml File
Go to the AndroidManifest.xml file and declare this service within the <application> element.
<service
android:name=".ExampleIntentService"
android:exported="false" />
Step 3: Working with the XML Files
Next, go to the activity_main.xml file, which represents the UI of the project. Below is the code for the activity_main.xml file. Comments are added inside the code to understand the code in more detail.
XML
<?xml version="1.0" encoding="utf-8"?><LinearLayout android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center" android:orientation="vertical"> <!-- Button to start the service --> <Button android:id="@+id/start_service_button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Start Service" /> </LinearLayout> |
Create a new class called ExampleIntentService that extends IntentService. Below is the code for the activity_example_intent_service.xml file. Comments are added inside the code to understand the code in more detail.
XML
<?xml version="1.0" encoding="utf-8"?><androidx.constraintlayout.widget.ConstraintLayout android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".ExampleIntentService"> <!-- TextView to display the title of the activity --> <TextView android:id="@+id/textView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Second Activity" android:textSize="32dp" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" /> </androidx.constraintlayout.widget.ConstraintLayout> |
Step 4: Working with the MainActivity & ExampleIntentService File
Go to the MainActivity File and refer to the following code. Below is the code for the MainActivity File. Comments are added inside the code to understand the code in more detail.
Kotlin
import android.content.Intentimport android.os.Bundleimport android.widget.Buttonimport androidx.appcompat.app.AppCompatActivity class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) // Get a reference to the start service button in the layout val startServiceButton = findViewById<Button>(R.id.start_service_button) // Set an OnClickListener for the button startServiceButton.setOnClickListener { // Create an Intent to start // the ExampleIntentService val intent = Intent(this@MainActivity, ExampleIntentService::class.java) // Start the service // using the intent startService(intent) } }} |
Java
import android.content.Intent;import android.os.Bundle;import android.widget.Button;import androidx.appcompat.app.AppCompatActivity; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // Get a reference to the start service button in the layout Button startServiceButton = findViewById(R.id.start_service_button); // Set an OnClickListener for the button startServiceButton.setOnClickListener(v -> { // Create an Intent to start // the ExampleIntentService Intent intent = new Intent(MainActivity.this, ExampleIntentService.class); // Start the service // using the intent startService(intent); }); }} |
Override the onHandleIntent() method to specify the task that you want to perform in the background. Below is the code for the ExampleIntentService File. Comments are added inside the code to understand the code in more detail.
Kotlin
import android.app.IntentServiceimport android.content.Intentimport android.util.Log class ExampleIntentService : IntentService("ExampleIntentService") { // Constructor with a name for the worker thread // The name is used only for debugging purposes. constructor(): super("ExampleIntentService") // This method is called on a worker thread // with a request to process. override fun onHandleIntent(intent: Intent?) { // Perform a task in the background Log.d("ExampleIntentService", "Task in progress") try { // Perform the task for 5 seconds Thread.sleep(5000) } catch (e: InterruptedException) { // Print the stack trace // if an interruption occurs e.printStackTrace() } Log.d("ExampleIntentService", "Task completed") }} |
Java
import android.app.IntentService;import android.content.Intent;import android.util.Log;import androidx.annotation.Nullable; public class ExampleIntentService extends IntentService { // Constructor public ExampleIntentService() { // Call superclass constructor with // the name of the worker thread super("ExampleIntentService"); } @Override protected void onHandleIntent(@Nullable Intent intent) { // Perform a task in the background Log.d("ExampleIntentService", "Task in progress"); // Simulate a long running task by // sleeping the thread for 5 seconds try { Thread.sleep(5000); } catch (InterruptedException e) { // Print stack trace if an // InterruptedException occurs e.printStackTrace(); } Log.d("ExampleIntentService", "Task completed"); }} |
Output:
