Perform Repeated Tasks in a Service
Description
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 ww . j a v a 2 s .co 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;
//from www. j ava 2s . 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.