android - How do I start a service which is defined in a different package?

Question

I have two apps, one runs in namespace com.gtosoft.voyager and the other is com.gtosoft.dash. From com.gtosoft.dash I would like to start up the service which is defined in com.gtosoft.voyager...

I think I need an intent, but what arg(s) would I pass to the intent before kicking it off with startService()?

If they were in the same package I could just use

Intent svc=new Intent (SettingsActivity.this,VoyagerService.class);
startService(svc);

Snippet of Manifest which defines the service

<application android:icon="@drawable/voyagercarlogo" android:label="@string/app_name" android:debuggable="false">

    <provider android:name="com.gtosoft.voyager.VoyagerCProvider" 
        android:authorities="com.gtosoft.voyager"/>

    <service android:name=".VoyagerService"/>

    <activity android:name=".SettingsActivity" 
            android:label="Voyager"
            android:configChanges="keyboardHidden|orientation">

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

Answer 1

While CommonsWare's answer was correct back in April of 2010, things have a changed and you need to actually setComponent to start a service in another application. For instance,

Activity in com.xyz.app1:

Intent i = new Intent();
String pkg = "com.xyz.app2";
String cls = "com.xyz.app2.MyService";
i.setComponent(new ComponentName(pkg, cls));
startService(i);