Create a Service that does a schedule task

Sometimes you need to do a schedule task for a fixed rate (repeatedly), like [check for emails], [check for battery], [update new Facebook status], etc…

The tip here is to use Service and implement a Timer running a TimerTask for an interval.

My sample here is that I like to get Date and Time in every 10 seconds and display a Toast notification to users.

Here how it looks:

Sample Schedule Task

So I create my own service called TimeService:

public class TimeService extends Service {
	// constant
	public static final long NOTIFY_INTERVAL = 10 * 1000; // 10 seconds

	// run on another Thread to avoid crash
	private Handler mHandler = new Handler();
	// timer handling
	private Timer mTimer = null;

	@Override
	public IBinder onBind(Intent intent) {
		return null;
	}

	@Override
	public void onCreate() {
		// cancel if already existed
		if(mTimer != null) {
			mTimer.cancel();
		} else {
			// recreate new
			mTimer = new Timer();
		}
		// schedule task
		mTimer.scheduleAtFixedRate(new TimeDisplayTimerTask(), 0, NOTIFY_INTERVAL);
	}

	class TimeDisplayTimerTask extends TimerTask {

		@Override
		public void run() {
			// run on another thread
			mHandler.post(new Runnable() {

				@Override
				public void run() {
					// display toast
					Toast.makeText(getApplicationContext(), getDateTime(),
							Toast.LENGTH_SHORT).show();
				}

			});
		}

		private String getDateTime() {
			// get date time in custom format
			SimpleDateFormat sdf = new SimpleDateFormat("[yyyy/MM/dd - HH:mm:ss]");
			return sdf.format(new Date());
		}

	}

It’s easy to understand, isn’t it?

Next is to register the TimerService to AndroidManifest for identification.

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/title_activity_main" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

        <service android:name=".TimeService"/>
    </application>

Our last step is to give a call for starting our service when activity executes.

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

        startService(new Intent(this, TimeService.class));
    }

Finally, just run on the phone and see the result.
The implementation is pretty straightforward and simple. You can freely use this way to create some schedule tasks for your applications.

Cheers,
Pete Houston