Android How to - Perform Repeated Tasks in a Service

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Repeated Tasks are tasks we runs persistently in the background. For example, you may write an alarm clock service.

We can use the Timer class within your service to execute a block of code at a regular time interval.

The following code shows how to Perform Repeated Tasks in a Service.

Example

Populate the MyService.java file with the following code:

package com.java2s.myapplication3.app;
/*from   w w  w . ja v  a2s  .  c o  m*/
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;

import java.util.Timer;
import java.util.TimerTask;

public class MyService extends Service {
    int counter = 0;
    static final int UPDATE_INTERVAL = 1000;
    private Timer timer = new Timer();

    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        doSomethingRepeatedly();
        return START_STICKY;
    }

    private void doSomethingRepeatedly() {
        timer.scheduleAtFixedRate(new TimerTask() {
            public void run() {
                Log.d("MyService", String.valueOf(++counter));
            }
        }, 0, UPDATE_INTERVAL);
    }

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

        if (timer != null) {
            timer.cancel();
        }

        Toast.makeText(this, "Service Destroyed", Toast.LENGTH_LONG).show();
    }
}

In the AndroidManifest.xml file, add the following statement:

<?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>

Main layout xml file

<?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>

Main Activity Java code

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
// w ww. j ava  2 s. c o m
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));
    }
}

Note

Clicking the Start Service button will start the service. To stop the service, click the Stop Service button.

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