Android Lesson 10 part 2: how to check if a service is running

We create an simple example to learn how to check if a service is running. In this example, we learn how to use Handler and Runnable in a service too. (You can read this tutorials for more information: Android Lesson 5: android.os.Handler)

Step 1: create new Android project

Step 2: create new class DemoService

package com.tutorialspots.service;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.util.Log;
import android.os.Handler;
import java.text.SimpleDateFormat;
import java.util.Date;


/**
 * Created by Tutorialspots on 1/8/2016.
 */
public class DemoService extends Service {
    public static Boolean running = false;
    private long step = 5000;
    private String currentDateandTime;
    private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    private Handler handler = new Handler();
    private Runnable runnable = new Runnable() {
        @Override
        public void run() {
            currentDateandTime = sdf.format(new Date());
            Log.i("DemoService", currentDateandTime);
            handler.postDelayed(this, step);
        }
    };

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        Log.i("DemoService", "Service onBind");
        return null;
    }

    @Override
    public void onCreate() {
        Log.i("DemoService", "Service onCreate");
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.i("DemoService", "Service onStartCommand");

        running = true;
        handler.postDelayed(runnable, step);

        return Service.START_STICKY;
    }

    @Override
    public void onDestroy() {
        handler.removeCallbacks(runnable);
        running = false;
        Log.i("DemoService", "Service onDestroy");
    }
}

Step 3: create 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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.tutorialspots.service.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TUTORIALSPOTS.COM"
        android:textColor="#FF0000"
        android:textSize="30dp"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:id="@+id/textView" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Start service"
        android:id="@+id/startbtn"
        android:layout_below="@+id/textView"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="62dp" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Stop service"
        android:id="@+id/stopbtn"
        android:layout_below="@+id/startbtn"
        android:layout_centerHorizontal="true" />
</RelativeLayout>

Step 4: file MainActivity.java

package com.tutorialspots.service;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    Button startbtn, stopbtn;

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

        // get buttons
        startbtn = (Button) findViewById(R.id.startbtn);
        stopbtn = (Button) findViewById(R.id.stopbtn);

        startbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(!DemoService.running){
                    startService(new Intent(MainActivity.this, DemoService.class));
                    Toast.makeText(getApplicationContext(), "Demo service has been started.", Toast.LENGTH_LONG).show();
                }
                else
                    Toast.makeText(getApplicationContext(), "Demo service is running.", Toast.LENGTH_LONG).show();
            }
        });

        stopbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(DemoService.running){
                    stopService(new Intent(MainActivity.this, DemoService.class));
                    Toast.makeText(getApplicationContext(), "Demo service has been stopped.", Toast.LENGTH_LONG).show();
                }
                else
                    Toast.makeText(getApplicationContext(), "Demo service don't run yet.", Toast.LENGTH_LONG).show();
            }
        });
    }
}

Step 5: file AndroidManifest.xml

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        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=".DemoService"
            android:exported="false"/>
    </application>

</manifest>

Step 6: Run for test

As soon as we click button start service, we see:

01-08 04:49:35.344 20564-20564/com.tutorialspots.service I/DemoService: Service onCreate
01-08 04:49:35.344 20564-20564/com.tutorialspots.service I/DemoService: Service onStartCommand
01-08 04:49:40.346 20564-20564/com.tutorialspots.service I/DemoService: 2016-01-08 04:49:40
01-08 04:49:45.351 20564-20564/com.tutorialspots.service I/DemoService: 2016-01-08 04:49:45

After 5s, we will get more debug message.