public class MyService  extends IntentService{
    AlarmManager alarmManager = null;
    PendingIntent alarmIntent = null;
    
    public MyService(){
        super("MyService");
    }
    
    public MyService(String name){
        super(name);
    }
    
    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }
    
    @Override
    public void onCreate() {
        super.onCreate();
        alarmManager = (AlarmManager)this.getSystemService(Context.ALARM_SERVICE);
        Intent intentTo = new Intent("com.yan.receive.MY_ALARM");
        alarmIntent = PendingIntent.getBroadcast(this, 0, intentTo, 0);
    }

    @Override
    protected void onHandleIntent(Intent arg0) {
        //final Context context = this.getApplicationContext();
        
        int alarmType = AlarmManager.ELAPSED_REALTIME_WAKEUP;
        long triggerAtMillis = SystemClock.elapsedRealtime()+(5*1000);//执行间隔时间5s
        long intervalMillis = 2*1000;    
        alarmManager.setInexactRepeating(alarmType, triggerAtMillis, intervalMillis, alarmIntent);
        
        System.out.println("============执行============");
    }
}

public class MyAlarmReceiver  extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent arg1) {
        Intent startIntent = new Intent(context, MyService.class);
        context.startService(startIntent);
    }

}

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment()).commit();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {
        Button btnStart;
        Button btnClose;
        AlarmManager alarmManager = null;
        PendingIntent alarmIntent = null;
        
        public PlaceholderFragment() {
        }
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container,false);
            
            btnStart = (Button)rootView.findViewById(R.id.btnStart);
            btnClose = (Button)rootView.findViewById(R.id.btnClose);

            btnStart.setOnClickListener(btnClickLIstener());
            btnClose.setOnClickListener(btnClickLIstener());
            
            return rootView;
        }
        
        OnClickListener btnClickLIstener(){
            return new OnClickListener(){
                @Override
                public void onClick(View arg0) {
                    switch(arg0.getId()){
                    case R.id.btnStart:
                        // 启动服务
                        Intent myIntent = new Intent(getActivity(),  MyService.class);
                        getActivity().startService(myIntent);
                        System.out.println("=========启动服务");
                        break;
                    case R.id.btnClose:
                        alarmManager = (AlarmManager)getActivity().getSystemService(Context.ALARM_SERVICE);
                        Intent intentTo = new Intent("com.yan.receive.MY_ALARM");
                        alarmIntent = PendingIntent.getBroadcast(getActivity(), 0, intentTo, 0);
                        if(null != alarmIntent){
                            alarmManager.cancel(alarmIntent);
                        }
                        System.out.println("=========停止Alarm");
                        getActivity().stopService(new Intent(getActivity(),  MyService.class));
                        System.out.println("=========停止服务");
                        break;
                    }
                }
            };
        }
    }
}

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.intentservice.MainActivity"
    tools:ignore="MergeRootFrame" />

<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.example.intentservice.MainActivity$PlaceholderFragment" >

    <Button
        android:id="@+id/btnStart"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="开启任务" />

    <Button
        android:layout_below="@id/btnStart"
        android:id="@+id/btnClose"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="关闭任务" />
</RelativeLayout>

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

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        
        <receiver
            android:name="com.yan.receive.MyAlarmReceiver"
            android:enabled="true"
            android:exported="false" >
            <intent-filter>
                <action android:name="com.yan.receive.MY_ALARM" />
            </intent-filter>
        </receiver>

        <service
            android:name="com.yan.service.MyService"
            android:enabled="true"
            android:exported="false" />
        
        <activity
            android:name="com.example.intentservice.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>