Android Interface Definition Language (AIDL)

Piyush Pandey

30 April 2019

An application cannot directly access the data of another application for security reasons. If you want to access the data from another application then AIDL will help
you to access those data. I have created two examples one of Server which creates the AIDL service and second Client which access the server data.

In order to implement ADIL, we need to follow the following steps:-

For Server App
1. Make one folder named AIDL in which your AIDL file resides.

interface IRemote
{
	  int add(int a, int b);
}

interface IRemote

{

int add(int a, int b);

}

2. Create the Service and Bind the IRemote Service as following

public class ArithmeticService extends Service{
    @Override
    public IBinder onBind(Intent intent) {
        // TODO Auto-generated method stub
        return mBinder;
    }
    /**
     * IRemote defnition is available here
     */
    private final IRemote.Stub mBinder = new IRemote.Stub() {
 
        @Override
        public int add(int a, int b) throws RemoteException {
            // TODO Auto-generated method stub
            return (a + b);
        }
 
    };
}

public class ArithmeticService extends Service{

@Override

public IBinder onBind(Intent intent) {

// TODO Auto-generated method stub

return mBinder;

}

/**

* IRemote defnition is available here

private final IRemote.Stub mBinder = new IRemote.Stub() {

@Override

public int add(int a, int b) throws RemoteException {

// TODO Auto-generated method stub

return (a + b);

}

};

}

3. Mention the service to android manifest file as following and also mention the unique action name

<service android:name=".ArithmeticService"
                     android:process=":remote">
                <intent-filter >
                    <action android:name="Mention your action Name"/>
                </intent-filter>
            </service>

<service android:name=".ArithmeticService"

android:process=":remote">

<intent-filter >

</intent-filter>

</service>

Client Example :

1. For getting access server data and functionality, we have to create the same aidl package as you used in the server example and create the same(copy) file as you created in the server example IRemote.aidl

2. Then for triggering the functionality, we need to create a ServiceConnection instance to handle:

a.Service connection event
b.Service disconnection event

ServiceConnection serviceConnection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName name, IBinder binder) {
Log.d("Srv", "Service connected!");
service = IRemote.Stub.asInterface((IBinder) service);
Log.d("Srv", "Service interface ["+service+"]");
}
 
@Override
public void onServiceDisconnected(ComponentName name) {
Log.d("Srv", "Service disconnected!");
service = null;
}

if(service == null)
            {
                Intent it = new Intent();
                it.setAction("com.remote.service.CALCULATOR");
                //binding to remote service
                bindService(it, serviceConnection Service.BIND_AUTO_CREATE);
            }

ServiceConnection serviceConnection = new ServiceConnection() {

@Override

public void onServiceConnected(ComponentName name, IBinder binder) {

Log.d("Srv", "Service connected!");

service = IRemote.Stub.asInterface((IBinder) service);

Log.d("Srv", "Service interface ["+service+"]");

}

@Override

public void onServiceDisconnected(ComponentName name) {

Log.d("Srv", "Service disconnected!");

service = null;

}

if(service == null)

{

Intent it = new Intent();

it.setAction("com.remote.service.CALCULATOR");

//binding to remote service

bindService(it, serviceConnection Service.BIND_AUTO_CREATE);

}

So for more information about AIDL file for passing more type of data and client-server app functionality, you can go through the for link:-

https://developer.android.com/guide/components/aidl#java