Communication between Activity and Service in Android?

This example demonstrates how do I communicate between Activity and Service in android.
Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.
Step 2 − Add the following code to res/layout/activity_main.xml.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context="MainActivity">
   <Button
      android:id="@+id/buttonStart"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_alignParentTop="true"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="74dp"
      android:text="Start Service" />
   <Button
      android:id="@+id/buttonStop"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerHorizontal="true"
      android:layout_centerVertical="true"
      android:text="Stop Service" />
</RelativeLayout>
Step 3 − Add the following code to src/MainActivity.java
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.support.v7.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
   Button buttonStart, buttonStop;
   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      buttonStart = findViewById(R.id.buttonStart);
      buttonStop = findViewById(R.id.buttonStop);
      buttonStart.setOnClickListener(this);
      buttonStop.setOnClickListener(this);
   }
   public void onClick(View src) {
      switch (src.getId()) {
         case R.id.buttonStart:
            startService(new Intent(this, MyService.class));
         break;
         case R.id.buttonStop:
            stopService(new Intent(this, MyService.class));
         break;
      }
   }
}
Step 4 − Create a new Service(MyService) and add the following code to MyServices.java
import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.widget.Toast;
public class MyService extends Service {
   MediaPlayer myPlayer;
   @Nullable
   @Override
   public IBinder onBind(Intent intent) {
      return null;
   }
   @Override
   public void onCreate() {
      Toast.makeText(this, "Service Created",
      Toast.LENGTH_LONG).show();
      myPlayer = MediaPlayer.create(this, R.raw.song);
      myPlayer.setLooping(false);
   }
   @Override
   public void onStart(Intent intent, int startId) {
      Toast.makeText(this, "Service Started",
      Toast.LENGTH_LONG).show();
      myPlayer.start();
   }
   @Override
   public void onDestroy() {
      Toast.makeText(this, "Service Stopped",
      Toast.LENGTH_LONG).show();
      myPlayer.stop();
   }
}
Step 5 − Add the following code to androidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest
   xmlns:android="http://schemas.android.com/apk/res/android"
   package="app.com.sample">
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <service
         android:name=".MyService"
         android:enabled="true"
         android:exported="true"></service>
      <activity android:name=".MainActivity">
         <intent-filter>
            <action
               android:name="android.intent.action.MAIN" />
            <category
               android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>
Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen −