Wednesday, 24 September 2008

Starting an Android Service at Boot time

A service that has to be started manually is an oxymoron, so starting a service at boot time is for many applications a must.

My tracklogging service is such an example, which should run whenever the phone is turned on, so that one can refer to the route travelled later. A further example is the much touted CarbonFootprint, which again relies on accurate measurements all the time, and not just when the user has turned it on.

The last post detailed how the TrackloggingService worked, but started the service only when the main activity was launched. Now comes the time to hook it into the Android boot sequence. Here is how:

After boot completes the Android system broadcasts an intent with the action android.intent.action.BOOT_COMPLETED. And now all we need is an IntentReceiver, now called a BroadcastReceiver, to listen and act on it. This is how this class looks:


public class LocationLoggerServiceManager extends BroadcastReceiver {

public static final String TAG = "LocationLoggerServiceManager";
@Override
public void onReceive(Context context, Intent intent) {
// just make sure we are getting the right intent (better safe than sorry)
if( "android.intent.action.BOOT_COMPLETED".equals(intent.getAction())) {
ComponentName comp = new ComponentName(context.getPackageName(), LocationLoggerService.class.getName());
ComponentName service = context.startService(new Intent().setComponent(comp));
if (null == service){
// something really wrong here
Log.e(TAG, "Could not start service " + comp.toString());
}
} else {
Log.e(TAG, "Received unexpected intent " + intent.toString());
}
}
}

The key is of course the onReceive() method. I have decided to check that it is actually the Intent I am expecting, but otherwise it is straightforward starting the service and return.

The receiver needs to be declared in the manifest, e.g. with the following entry:

<receiver android:name=".LocationLoggerServiceManager"
android:enabled="true"
android:exported="false"
android:label="LocationLoggerServiceManager">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>


Furthermore this class listen to this specific event needs to be declared in the security settings:

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />


That's it. Now the service will be started as soon a Android has finished booting.
Now we will need something to make this user-configurable...

9 comments:

jeremy.org said...

Thanks! This was useful.

cryptyk said...

This was very helpful. It got me unstuck.

Thank you.

Abhi said...

Hi,

I am getting the following error when i added your code

Error : "The application has stopped unexpectedly please try again"

Ludwig said...

Without more information I do not think anyone will be able to help you. It looks like the code worked for others. It might be best to have a look in the debugger what is happening in your code. I assume it is some form of ActivityNotFound exception...

AF-SH-ISH said...
This comment has been removed by the author.
leo said...

thanks you! And I have another question. How can I start the "LocationLoggerServiceManage" or need to register it?

leo said...

Thanks. I'm new to andriod and JAVA. I want to know how to start the "LocationLoggerServiceManager". Thanks in advance.

herri said...

This seems to be working in a emulator, but on an actual device it does not. I tested the code on both, 2.1 and 2.2 ZTE Blade Android handsets.

The other device requests for a PIN code and the other does not have SIM card in it, so it cannot be that the signal broadcasted would be delayed, causing a timeout or something.

Hopefully someone will get the code fixed?

yetiken software said...

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