Android™ Application Development - Bahar Ali Khan

Chapter 11: Advanced Android Development
Methods can take zero or more parameters and return void or a supported type. If you defi ne a method
that takes one or more parameters, you need to use a directional tag to indicate if the parameter is a
value or reference type using the in, out, and inout keywords.
Where possible, you should limit the direction of each parameter, as marshaling parameters is an expensive
operation.
The following sample shows a basic AIDL defi nition for the IEarthquakeService.aidl fi le:
package com.paad.earthquake;
import com.paad.earthquake.Quake;
interface IEarthquakeService {
List getEarthquakes();
}
void refreshEarthquakes();
Implementing and Exposing the IPC Interface
If you’re using the ADT plug-in, saving the AIDL fi le will automatically code-generate a Java interface
fi le. This interface will include an inner Stub class that implements the interface as an abstract class.
Have your Service extend the Stub and implement the functionality required. Typically, this will be
done using a private fi eld variable within the Service whose functionality you’ll be exposing.
The following code snippet shows an implementation of the IEarthquakeService AIDL defi nition
created above:
IBinder myEarthquakeServiceStub = new IEarthquakeService.Stub() {
public void refreshEarthquakes() throws RemoteException {
EarthquakeService.this.refreshEarthquakes();
}
public List getEarthquakes() throws RemoteException {
ArrayList result = new ArrayList();
ContentResolver cr = EarthquakeService.this.getContentResolver();
Cursor c = cr.query(EarthquakeProvider.CONTENT_URI, null, null, null, null);
if (c.moveToFirst())
do {
Double lat = c.getDouble(EarthquakeProvider.LATITUDE_COLUMN);
Double lng = c.getDouble(EarthquakeProvider.LONGITUDE_COLUMN);
Location location = new Location(“dummy”);
location.setLatitude(lat);
location.setLongitude(lng);
String details = c.getString(EarthquakeProvider.DETAILS_COLUMN);
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