Create your first IntentService

package com.java2s.myapplication3.app;
//from w w  w . ja  va2 s.  c om
import java.net.MalformedURLException;
import java.net.URL;

import android.app.IntentService;
import android.content.Intent;
import android.util.Log;

public class MyService extends IntentService {

    public MyService() {
        super("MyIntentServiceName");
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        try {
            int result = DownloadFile(new URL("http://www.amazon.com/somefile.pdf"));
            Log.d("IntentService", "Downloaded " + result + " bytes");
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
    }

    private int DownloadFile(URL url) {
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return 100;
    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.java2s.Services"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="14" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
         android:label="@string/app_name"
         android:name=".ServicesActivity" >
         <intent-filter >
             <action android:name="android.intent.action.MAIN" />

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

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

<Button android:id="@+id/btnStartService"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Start Service"
    android:onClick="startService"/>

<Button android:id="@+id/btnStopService"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Stop Service"
    android:onClick="stopService" />

</LinearLayout>

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
/*from w w  w .j a v a 2s. c  om*/
public class MainActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    public void startService(View view) {
           startService(new Intent(getBaseContext(), MyService.class));
    }

    public void stopService(View view) {
       stopService(new Intent(getBaseContext(),MyService.class));
    }
}