IntentService Tutorial

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical"
    android:padding="16dp"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/edit_text_input"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Input" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="startService"
        android:text="Start Service" />

</LinearLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.codinginflow.intentserviceexample">

    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />

    <application
        android:name=".App"
        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">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service android:name=".ExampleIntentService" />
    </application>

</manifest>

App.java

package com.codinginflow.intentserviceexample;

import android.app.Application;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.os.Build;

public class App extends Application {
    public static final String CHANNEL_ID = "exampleServiceChannel";

    @Override
    public void onCreate() {
        super.onCreate();

        createNotificationChannel();
    }

    private void createNotificationChannel() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel serviceChannel = new NotificationChannel(
                    CHANNEL_ID,
                    "Example Service Channel",
                    NotificationManager.IMPORTANCE_DEFAULT
            );

            NotificationManager manager = getSystemService(NotificationManager.class);
            manager.createNotificationChannel(serviceChannel);
        }
    }
}

ExampleIntentService.java

package com.codinginflow.intentserviceexample;

import android.app.IntentService;
import android.app.Notification;
import android.content.Intent;
import android.os.Build;
import android.os.PowerManager;
import android.os.SystemClock;
import android.support.annotation.Nullable;
import android.support.v4.app.NotificationCompat;
import android.util.Log;

import static com.codinginflow.intentserviceexample.App.CHANNEL_ID;

public class ExampleIntentService extends IntentService {
    private static final String TAG = "ExampleIntentService";

    private PowerManager.WakeLock wakeLock;

    public ExampleIntentService() {
        super("ExampleIntentService");
        setIntentRedelivery(true);
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Log.d(TAG, "onCreate");

        PowerManager powerManager = (PowerManager) getSystemService(POWER_SERVICE);
        wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
                "ExampleApp:Wakelock");
        wakeLock.acquire();
        Log.d(TAG, "Wakelock acquired");

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
                    .setContentTitle("Example IntentService")
                    .setContentText("Running...")
                    .setSmallIcon(R.drawable.ic_android)
                    .build();

            startForeground(1, notification);
        }
    }

    @Override
    protected void onHandleIntent(@Nullable Intent intent) {
        Log.d(TAG, "onHandleIntent");

        String input = intent.getStringExtra("inputExtra");

        for (int i = 0; i < 10; i++) {
            Log.d(TAG, input + " - " + i);
            SystemClock.sleep(1000);
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.d(TAG, "onDestroy");

        wakeLock.release();
        Log.d(TAG, "Wakelock released");
    }
}

MainActivity.java

package com.codinginflow.intentserviceexample;

import android.content.Intent;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {
    private EditText editTextInput;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        editTextInput = findViewById(R.id.edit_text_input);
    }

    public void startService(View v) {
        String input = editTextInput.getText().toString();

        Intent serviceIntent = new Intent(this, ExampleIntentService.class);
        serviceIntent.putExtra("inputExtra", input);

        ContextCompat.startForegroundService(this, serviceIntent);
    }
}