Develop Reference

How to communicate with HostApduService from an Activity

I have asked this question here but it was marked as duplicate -
however I didn't find any solution helpful mentioned in comments.
Here, I am asking again with more details ...
I am doing a sample app (PoC) on HCE and using HostApduService as per Android user guide. I have created two apps
1) ReaderApp - acting as card reader
2) HCEApp - emulating a card
In HCEApp, I have created a class 'MyService' extending HostApduService
public class MyService extends HostApduService {
private int messageCounter;
private final String TAG = "MyService";
Intent mIntent;
#Override
public void onCreate() {
super.onCreate();
Log.i(TAG, "onCreate");
mIntent = new Intent(this, MyActivity.class);
mIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(mIntent);
}
/**
* returned bytes will be sent as response. This method runs in Main thread
* so return ASAP.
*/
#Override
public byte[] processCommandApdu(byte[] apdu, Bundle extras) {
if (selectAidApdu(apdu)) {
Log.i(TAG, "Application selected");
return getWelcomeMessage();
} else {
Log.i(TAG, "Received: " + new String(apdu));
return getNextMessage();
}
}
private byte[] getWelcomeMessage() {
return "Hello Desktop!".getBytes();
}
private byte[] getNextMessage() {
return ("Message from android: " + messageCounter++).getBytes();
}
private boolean selectAidApdu(byte[] apdu) {
if (apdu != null) {
for (byte b : apdu) {
System.out.printf("0x%02X", b);
}
}
return apdu.length >= 2 && apdu[0] == (byte) 0
&& apdu[1] == (byte) 0xa4;
}
#Override
public void onDeactivated(int reason) {
Log.i(TAG, "Deactivated: " + reason);
}
#Override
public boolean onUnbind(Intent intent) {
return super.onUnbind(intent);
}
}
As you can see in onCreate(), I am launching MyActivity provides user to enter some information and needs to be sent back to MyService.
I think I can not use binding as 'onBind()' is declared final in HostApduService as below
#Override
public final IBinder onBind(Intent intent) {
return mMessenger.getBinder();
}
Please let me know if I am understading it correctly. Appreciate any help.
Thanks
iuq

Whether you can use onBind or not I do not know, but I recently worked with a BroadcastReceiver from which I had to start a Service. You cannot bind a Service from a BroadcastReceiver according to docs, you can only start it. I needed to send some data to the Service from my BroadcastReceiver at some later point, and since the binder techniques was not available to me, I had to find a different way to communicate with the Service, much like your case where you don't have a reference to it.
I did some research but could not find any solution, but then I remembered that you can pass intent data with the startService(intent) call. I start my Service work in onCreate instead, as onCreate is only called once when the Service is created.
In your Activity
public void sendDataToService(){
Intent intent = new Intent(context, MyService.class);
intent.putExtra("message", SOME_DATA);
context.startService(intent);
}
In your Service
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
// Check if intent has extras
if(intent.getExtras() != null){
// Get message
int message = intent.getExtras().getInt("message");
}
return START_NOT_STICKY;
}
This may be some sort what of a hack since "startService" does not sound like it should be used to send messages, and am not sure if this is exactly what you need, but it worked for me, so I hope it works for you. Cheers
Edit: BTW. I use it to tell a LocationService that a particular activity no longer want location updates.

I ended up taking a different approach to solving this same problem. When I bind to my HostApduService subclass, I grab a handle to the Messenger interface returned by the HostApduService onBind implementation.
Here's some sample code. This would all go in your activity implementation (calling it MyActivity here, communicating with MyHostApduServiceSubclass). Here's what MyActivity would need to include:
private Messenger mAPDUMessenger;
...
#Override
protected void onStart() {
super.onStart();
Context context = getApplicationContext();
Intent apduIntent = new Intent(montext, ContactlessApduService.class);
context.bindService(apduIntent, mAPDUConnection, Context.BIND_AUTO_CREATE);
}
...
private ServiceConnection mAPDUConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName className, IBinder service) {
// The HostApduService has a final override on the onBind() service method that returns
// an IMessageHandler interface that we can grab and use to send messages back to the
// terminal - would be better to get a handle to the running instance of the service so
// that we could make use of the HostApduService#sendResponseApdu public method
mAPDUMessenger = new Messenger(service);
registerAPDUMessengerIntentFilters();
// ^ This method sets up my handlers for local broadcast messages my BroadcastReceiver processes.
}
...
}
...
private void registerAPDUMessengerIntentFilters() {
LocalBroadcastManager lbm = LocalBroadcastManager.getInstance(MyActivity.this);
IntentFilter intentFilter = new IntentFilter(MyHostApduServiceSubclass.ACTION_PPSE_APDU_SELECT);
lbm.registerReceiver(apduMessageBroadcastReceiver, intentFilter);
}
...
BroadcastReceiver apduMessageBroadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(MyHostApduServiceSubclass.ACTION_PPSE_APDU_SELECT)) {
sendResponseApdu(MyActivity.PPSE_APDU_SELECT_RESPONSE_BYTES);
}
}
};
...
public final void sendResponseApdu(byte[] responseApdu) {
Message responseMsg = Message.obtain(null, MyHostApduServiceSubclass.MSG_RESPONSE_APDU);
// ^ Note here that because MSG_RESPONSE_APDU is the message type
// defined in the abstract HostApduService class, I had to override
// the definition in my subclass to expose it for use from MyActivity.
// Same with the KEY_DATA constant value below.
Bundle dataBundle = new Bundle();
dataBundle.putByteArray(MyHostApduServiceSubclass.KEY_DATA, responseApdu);
responseMsg.setData(dataBundle);
try {
mAPDUMessenger.send(responseMsg);
} catch (RemoteException e) {
// Do something with the failed message
}
}
And then your HostApduService subclass would just need to send a broadcast to your activity indicating what APDU command was received. Here is what would need to be included in MyHostApduServiceSubclass:
public static final String ACTION_PPSE_APDU_SELECT = "ACTION_PPSE_APDU_SELECT";
// Abstract super class constant overrides
public static final String KEY_DATA = "data";
public static final int MSG_RESPONSE_APDU = 1;
#Override
public byte[] processCommandApdu(byte[] commandApdu, Bundle extras) {
Context context = getApplicationContext();
LocalBroadcastManager lbm = LocalBroadcastManager.getInstance(context);
if (Arrays.equals(MyHostApduServiceSubclass.PPSE_APDU_SELECT_BYTES, commandApdu)) {
lbm.sendBroadcast(new Intent(ACTION_PPSE_APDU_SELECT));
}
return null;
// ^ Note the need to return null so that the other end waits for the
// activity to send the response via the Messenger handle
}

service instance still null after binding

I have a service, and I am trying to bind an activity to it. The problem is...after running bindService(..), the service instance that Im setting inside the serviceconnection is still null, and I dont know why.
private ConnectionService conn;
private ServiceConnection mConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName name, IBinder service) {
conn = ((ConnectionService.ConnectionBinder)service).getService();
Toast.makeText(main_tab_page.this, "Connected", Toast.LENGTH_SHORT)
.show();
}
#Override
public void onServiceDisconnected(ComponentName name) {
conn = null;
}
};
#Override
protected void onStart()
{
super.onStart();
//check start connection service
if(conn == null)
{
Intent serviceIntent = new Intent(this, ConnectionService.class);
bindService(serviceIntent, mConnection, Context.BIND_AUTO_CREATE);
}
//connect to server
server.conn = conn;
//THIS STATEMENT FAILS: NULL REFERENCE, conn is Null here, and I have no idea why
conn.ConnectToServer(server);
server.StartReader();
}
Yes: The service is defined in the manifest.
Yes: I can start the service from the MAIN Activity (this code resides in an activity that is started BY the main activity, which is where i need to bind to the service) I have checked to make sure the service actually does start....it does
According to every example i've managed to locate for bound services, this should be working. Can anyone tell me why its not?
Edit: Add service code definition
public class ConnectionService extends Service{
private BlockingQueue<String> MessageQueue;
public final IBinder myBind = new ConnectionBinder();
public class ConnectionBinder extends Binder {
ConnectionService getService() {
return ConnectionService.this;
}
}
private Socket socket;
private BufferedWriter writer;
private BufferedReader reader;
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
if(MessageQueue == null)
MessageQueue = new LinkedBlockingQueue<String>();
return Service.START_NOT_STICKY;
}
#Override
public IBinder onBind(Intent arg0) {
return myBind;
}
//some other code that has everything to do with what the service does, and nothing to do with how it should be started/run
}

Please check the service is declared in Manifest.

How to get progress dialog until get the response from service in android?

I am using service for running long background tasks in my application, in the service these functions are running login to XMPP and getting some data from XMPP server. i want to show the progress bar upto login completed. How to get response from service to activity to Update progress bar properly to avoid some exceptions in UI.
I am calling service like this
final Intent gtalk_intent = new Intent(AccountsActivity.this, GtalkService.class);
gtalk_intent.putExtra("user_name", acc.getAcc_Name());
gtalk_intent.putExtra("user_pass", acc.getAcc_Pass());
startService(gtalk_intent);
this is the code from service
public class PmService extends Service {
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
public class PmBinder extends Binder {
public PmService getService() {
return PmService.this;
}
}
#Override
public void onCreate() {
super.onCreate();
context = this;
app_preferences = new AppPreferences(this);
chat_source = new ChatsDataSource(this);
chat_source.open();
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Bundle extras = intent.getExtras();
if(extras == null) {
full_name = extras.getString("user_name");
if(full_name.contains("#")) {
String[] _na = full_name.split("#");
U_name = _na[0];
}
U_pass = extras.getString("user_pass");
}
new PmAsync().execute();
return START_STICKY;
}
private class PmAsync extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
}
#Override
protected Void doInBackground(Void... params) {
SASLAuthentication.supportSASLMechanism("PLAIN", 0);
ConnectionConfiguration config = new ConnectionConfiguration(server_host, SERVER_PORT, SERVICE_NAME);
configure(ProviderManager.getInstance());
m_connection = new XMPPConnection(config);
try {
m_connection.connect();
Roster.setDefaultSubscriptionMode(Roster.SubscriptionMode.manual);
} catch (XMPPException e) {
e.printStackTrace();
}
try {
m_connection.login(U_name, U_pass);
setPacketFilters();
} catch (XMPPException e) {
}
return null;
}
}
i want to show the progress bar upto login completed, how to response from service after login completed?

Via Binder you can send callbacks to your Activity, which means that you can update UI.
Add according method to your Binder (let's name it onProgress)
From your AsyncTask call method of this Binder
In order to know about progress updates consider using Observer pattern (in other words - your Activity should listen for updates of your Binder, or more specifically - of calling Binder.onProgress method)

You can update the progress bar via overriding the onProgress() method
here is a close to your case that you can refer to.link

onServiceConnected sometimes not called after bindService on some devices

I've looked at a number of other threads with similar titles, and none seem to cover my problem. So, here goes.
I'm using the Google market expansion files (apkx) library and sample code, with a few modifications. This code relies on receiving callbacks from a service which handles background downloading, licence checks etc.
I have a bug where the service doesn't get correctly attached, which results in a softlock. To make this more unhelpful, this bug never happens on some devices, but occurs about two thirds of the time on other devices. I believe it to be independent of Android version, certainly I have two devices running 2.3.4, one of which (a Nexus S) doesn't have the problem, the other (an HTC Evo 3D) does.
To attempt to connect to the service, bindService is called and returns true. OnBind then gets called as expected and returns a sensible value but (when the bug occurs) onServiceConnected doesn't happen (I've waited 20 minutes just in case).
Has anyone else seen anything like this? If not, any guesses for what I might have done to cause such behaviour? If no-one has any thoughts, I'll post some code tomorrow.
EDIT: Here's the relevant code. If I've missed anything, please ask.
Whilst adding this code, I found a minor bug. Fixing it caused the frequency of the problem I'm trying to solve to change from 2 times in 3 to about 1 time in 6 on the phone I'm testing it on; no idea about effects on other phones. This continues to suggest to me a race condition or similar, but I've no idea what with.
OurDownloaderActivity.java (copied and changed from Google sample code)
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
//Test the licence is up to date
//if (current stored licence has expired)
{
startLicenceCheck();
initializeDownloadUI();
return;
}
...
}
#Override
protected void onResume() {
if (null != mDownloaderClientStub) {
mDownloaderClientStub.connect(this);
}
super.onResume();
}
private void startLicenceCheck()
{
Intent launchIntent = OurDownloaderActivity.this
.getIntent();
Intent intentToLaunchThisActivityFromNotification = new Intent(OurDownloaderActivity
.this, OurDownloaderActivity.this.getClass());
intentToLaunchThisActivityFromNotification.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK |
Intent.FLAG_ACTIVITY_CLEAR_TOP);
intentToLaunchThisActivityFromNotification.setAction(launchIntent.getAction());
if (launchIntent.getCategories() != null) {
for (String category : launchIntent.getCategories()) {
intentToLaunchThisActivityFromNotification.addCategory(category);
}
}
// Build PendingIntent used to open this activity from Notification
PendingIntent pendingIntent = PendingIntent.getActivity(OurDownloaderActivity.this,
0, intentToLaunchThisActivityFromNotification,
PendingIntent.FLAG_UPDATE_CURRENT);
DownloaderService.startLicenceCheck(this, pendingIntent, OurDownloaderService.class);
}
initializeDownloadUI()
{
mDownloaderClientStub = DownloaderClientMarshaller.CreateStub
(this, OurDownloaderService.class);
//do a load of UI setup
...
}
//This should be called by the Stub's onServiceConnected method
/**
* Critical implementation detail. In onServiceConnected we create the
* remote service and marshaler. This is how we pass the client information
* back to the service so the client can be properly notified of changes. We
* must do this every time we reconnect to the service.
*/
#Override
public void onServiceConnected(Messenger m) {
mRemoteService = DownloaderServiceMarshaller.CreateProxy(m);
mRemoteService.onClientUpdated(mDownloaderClientStub.getMessenger());
}
DownloaderService.java (in Google market expansion library but somewhat edited )
//this is the onBind call that happens fine; the value it returns is definitely not null
#Override
public IBinder onBind(Intent paramIntent) {
return this.mServiceMessenger.getBinder();
}
final private IStub mServiceStub = DownloaderServiceMarshaller.CreateStub(this);
final private Messenger mServiceMessenger = mServiceStub.getMessenger();
//MY CODE, derived from Google's code
//I have seen the bug occur with a service started by Google's code too,
//but this code happens more often so is more repeatably related to the problem
public static void startLicenceCheck(Context context, PendingIntent pendingIntent, Class<?> serviceClass)
{
String packageName = serviceClass.getPackage().getName();
String className = serviceClass.getName();
Intent fileIntent = new Intent();
fileIntent.setClassName(packageName, className);
fileIntent.putExtra(EXTRA_LICENCE_EXPIRED, true);
fileIntent.putExtra(EXTRA_PENDING_INTENT, pendingIntent);
context.startService(fileIntent);
}
#Override
protected void onHandleIntent(Intent intent) {
setServiceRunning(true);
try {
final PendingIntent pendingIntent = (PendingIntent) intent
.getParcelableExtra(EXTRA_PENDING_INTENT);
if (null != pendingIntent)
{
mNotification.setClientIntent(pendingIntent);
mPendingIntent = pendingIntent;
} else if (null != mPendingIntent) {
mNotification.setClientIntent(mPendingIntent);
} else {
Log.e(LOG_TAG, "Downloader started in bad state without notification intent.");
return;
}
if(intent.getBooleanExtra(EXTRA_LICENCE_EXPIRED, false))
{
//we are here due to startLicenceCheck
updateExpiredLVL(this);
return;
}
...
}
}
//MY CODE, based on Google's, again
public void updateExpiredLVL(final Context context) {
Context c = context.getApplicationContext();
Handler h = new Handler(c.getMainLooper());
h.post(new LVLExpiredUpdateRunnable(c));
}
private class LVLExpiredUpdateRunnable implements Runnable
{
LVLExpiredUpdateRunnable(Context context) {
mContext = context;
}
final Context mContext;
#Override
public void run() {
setServiceRunning(true);
mNotification.onDownloadStateChanged(IDownloaderClient.STATE_LVL_UPDATING);
String deviceId = getDeviceId(mContext);
final APKExpansionPolicy aep = new APKExpansionPolicy(mContext,
new AESObfuscator(getSALT(), mContext.getPackageName(), deviceId));
// Construct the LicenseChecker with a Policy.
final LicenseChecker checker = new LicenseChecker(mContext, aep,
getPublicKey() // Your public licensing key.
);
checker.checkAccess(new LicenseCheckerCallback() {
...
});
}
}
DownloaderClientMarshaller.java (in Google market expansion library)
public static IStub CreateStub(IDownloaderClient itf, Class<?> downloaderService) {
return new Stub(itf, downloaderService);
}
and the Stub class from the same file:
private static class Stub implements IStub {
private IDownloaderClient mItf = null;
private Class<?> mDownloaderServiceClass;
private boolean mBound;
private Messenger mServiceMessenger;
private Context mContext;
/**
* Target we publish for clients to send messages to IncomingHandler.
*/
final Messenger mMessenger = new Messenger(new Handler() {
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_ONDOWNLOADPROGRESS:
Bundle bun = msg.getData();
if ( null != mContext ) {
bun.setClassLoader(mContext.getClassLoader());
DownloadProgressInfo dpi = (DownloadProgressInfo) msg.getData()
.getParcelable(PARAM_PROGRESS);
mItf.onDownloadProgress(dpi);
}
break;
case MSG_ONDOWNLOADSTATE_CHANGED:
mItf.onDownloadStateChanged(msg.getData().getInt(PARAM_NEW_STATE));
break;
case MSG_ONSERVICECONNECTED:
mItf.onServiceConnected(
(Messenger) msg.getData().getParcelable(PARAM_MESSENGER));
break;
}
}
});
public Stub(IDownloaderClient itf, Class<?> downloaderService) {
mItf = itf;
mDownloaderServiceClass = downloaderService;
}
/**
* Class for interacting with the main interface of the service.
*/
private ServiceConnection mConnection = new ServiceConnection() {
//this is the critical call that never happens
public void onServiceConnected(ComponentName className, IBinder service) {
// This is called when the connection with the service has been
// established, giving us the object we can use to
// interact with the service. We are communicating with the
// service using a Messenger, so here we get a client-side
// representation of that from the raw IBinder object.
mServiceMessenger = new Messenger(service);
mItf.onServiceConnected(
mServiceMessenger);
mBound = true;
}
public void onServiceDisconnected(ComponentName className) {
// This is called when the connection with the service has been
// unexpectedly disconnected -- that is, its process crashed.
mServiceMessenger = null;
mBound = false;
}
};
#Override
public void connect(Context c) {
mContext = c;
Intent bindIntent = new Intent(c, mDownloaderServiceClass);
bindIntent.putExtra(PARAM_MESSENGER, mMessenger);
if ( !c.bindService(bindIntent, mConnection, 0) ) {
if ( Constants.LOGVV ) {
Log.d(Constants.TAG, "Service Unbound");
}
}
}
#Override
public void disconnect(Context c) {
if (mBound) {
c.unbindService(mConnection);
mBound = false;
}
mContext = null;
}
#Override
public Messenger getMessenger() {
return mMessenger;
}
}
DownloaderServiceMarshaller.java (in Google market expansion library, unchanged)
private static class Proxy implements IDownloaderService {
private Messenger mMsg;
private void send(int method, Bundle params) {
Message m = Message.obtain(null, method);
m.setData(params);
try {
mMsg.send(m);
} catch (RemoteException e) {
e.printStackTrace();
}
}
public Proxy(Messenger msg) {
mMsg = msg;
}
#Override
public void requestAbortDownload() {
send(MSG_REQUEST_ABORT_DOWNLOAD, new Bundle());
}
#Override
public void requestPauseDownload() {
send(MSG_REQUEST_PAUSE_DOWNLOAD, new Bundle());
}
#Override
public void setDownloadFlags(int flags) {
Bundle params = new Bundle();
params.putInt(PARAMS_FLAGS, flags);
send(MSG_SET_DOWNLOAD_FLAGS, params);
}
#Override
public void requestContinueDownload() {
send(MSG_REQUEST_CONTINUE_DOWNLOAD, new Bundle());
}
#Override
public void requestDownloadStatus() {
send(MSG_REQUEST_DOWNLOAD_STATE, new Bundle());
}
#Override
public void onClientUpdated(Messenger clientMessenger) {
Bundle bundle = new Bundle(1);
bundle.putParcelable(PARAM_MESSENGER, clientMessenger);
send(MSG_REQUEST_CLIENT_UPDATE, bundle);
}
}
private static class Stub implements IStub {
private IDownloaderService mItf = null;
final Messenger mMessenger = new Messenger(new Handler() {
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_REQUEST_ABORT_DOWNLOAD:
mItf.requestAbortDownload();
break;
case MSG_REQUEST_CONTINUE_DOWNLOAD:
mItf.requestContinueDownload();
break;
case MSG_REQUEST_PAUSE_DOWNLOAD:
mItf.requestPauseDownload();
break;
case MSG_SET_DOWNLOAD_FLAGS:
mItf.setDownloadFlags(msg.getData().getInt(PARAMS_FLAGS));
break;
case MSG_REQUEST_DOWNLOAD_STATE:
mItf.requestDownloadStatus();
break;
case MSG_REQUEST_CLIENT_UPDATE:
mItf.onClientUpdated((Messenger) msg.getData().getParcelable(
PARAM_MESSENGER));
break;
}
}
});
public Stub(IDownloaderService itf) {
mItf = itf;
}
#Override
public Messenger getMessenger() {
return mMessenger;
}
#Override
public void connect(Context c) {
}
#Override
public void disconnect(Context c) {
}
}
/**
* Returns a proxy that will marshall calls to IDownloaderService methods
*
* #param ctx
* #return
*/
public static IDownloaderService CreateProxy(Messenger msg) {
return new Proxy(msg);
}
/**
* Returns a stub object that, when connected, will listen for marshalled
* IDownloaderService methods and translate them into calls to the supplied
* interface.
*
* #param itf An implementation of IDownloaderService that will be called
* when remote method calls are unmarshalled.
* #return
*/
public static IStub CreateStub(IDownloaderService itf) {
return new Stub(itf);
}

What is the proper way to update activity based on Network responses?

I am implementing an application which is kind of VOIP application. So my application is kind of network application. Now I want to implement two part in my application, one is GUI part and one is network part. My GUI part will just contain activities and handling of user interaction. My Network part should handle all network related activities like handling incoming network data and sending data to network based on GUI interaction. Now whenever there is any incoming data, I want to update some activity whose reference is not there in Network module. So what could be the best way to update activity from some other class? In my case some other class is my Network class. So in short I would like to ask that what should be the architecture in such scenario? i.e. Network part should run in separate thread and from there it should update GUI?

Depending on the type/size of data you need to send to the activity, you can use one of a number of options.
Use one of the methods described here.
Use a BroadcastReceiver: register it in the Activity and then fire off matching Intents in the Service that handles the networking code.
Make your Activity bind to your Service and then pass in a Handler that you send Messages to.

I have written apps like this, and I prefer the Handler method. In fact I have written an Abstract Activity class to do all the hard work and simply extend it in any activity that want to be notified of a change.
To Use the following code, just get your Activity to extend UpdatableActivity and override the dataUpdated() method. This method is called when your Service notifies the handler that data has been updated. In the Service code put your code to do an update in the update() method (Or modify to call your existing code). This allows an activity to call this.updateService() to force an update. The service can call the sendMessageToUI() method to notify all interested activities that the data has been updated.
Here is what the abstract activity looks like:
public abstract class UpdatableActivity extends Activity {
public static final String TAG = "UpdatableActivity (Abstract)";
private final Messenger mMessenger = new Messenger(new IncomingHandler());
private Messenger mService = null;
private boolean mIsBound;
protected class IncomingHandler extends Handler {
#Override
public void handleMessage(Message msg) {
if (Constants.LOG_DEBUG) Log.d(TAG, "Service has notified us of an update: ");
switch (msg.arg1) {
case UpdateService.MSG_DATA_UPDATED:
dataUpdated();
break;
default: super.handleMessage(msg);
}
}
}
private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder service) {
mService = new Messenger(service);
try {
Message msg = Message.obtain(null, UpdateService.MSG_REGISTER_CLIENT);
msg.replyTo = mMessenger;
mService.send(msg);
} catch (RemoteException e) {
// In this case the service has crashed before we could even do anything with it
}
}
public void onServiceDisconnected(ComponentName className) {
// This is called when the connection with the service has been unexpectedly disconnected - process crashed.
mService = null;
}
};
/**Override this method in you acctivity to handle the update */
public abstract void dataUpdated();
void doBindService() {
if (Constants.LOG_DEBUG) Log.d(TAG, "Binding to service...");
bindService(new Intent(this, UpdateService.class), mConnection, Context.BIND_AUTO_CREATE);
mIsBound = true;
}
void doUnbindService() {
if (mIsBound) {
// If we have received the service, and hence registered with it, then now is the time to unregister.
if (mService != null) {
try {
Message msg = Message.obtain(null, UpdateService.MSG_UNREGISTER_CLIENT);
msg.replyTo = mMessenger;
mService.send(msg);
} catch (RemoteException e) {
// There is nothing special we need to do if the service has crashed.
}
}
// Detach our existing connection.
unbindService(mConnection);
mIsBound = false;
}
}
public void updateService() {
if (Constants.LOG_DEBUG) Log.d(TAG,"Updating Service...");
if (mIsBound) {
if (mService != null) {
try {
Message msg = Message.obtain(null, UpdateService.MSG_SET_INT_VALUE, UpdateService.MSG_DO_UPDATE, 0);
msg.replyTo = mMessenger;
mService.send(msg);
} catch (RemoteException e) {
if (Constants.LOG_ERROR) Log.e(TAG,Log.getStackTraceString(e));
}
}
} else {
if (Constants.LOG_DEBUG) Log.d(TAG, "Fail - service not bound!");
}
}
pu
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.doBindService();
}
#Override
protected void onDestroy() {
super.onDestroy();
try {
doUnbindService();
} catch (Throwable t) {
if (Constants.LOG_ERROR) Log.e(TAG, "Failed to unbind from the service", t);
}
}
}
And here is what the Service looks Like:
public class UpdateService extends Service {
public static final String TAG = "UpdateService";
public static final int MSG_DATA_UPDATED = 0;
public static final int MSG_REGISTER_CLIENT = 1;
public static final int MSG_UNREGISTER_CLIENT = 2;
public static final int MSG_DO_UPDATE = 3;
public static final int MSG_SET_INT_VALUE = 4;
private static boolean isRunning = false;
private Handler handler = new IncomingHandler();
private final Messenger mMessenger = new Messenger(handler);
private ArrayList<Messenger> mClients = new ArrayList<Messenger>(); // Keeps track of all current registered clients.
#Override
public IBinder onBind(Intent intent) {
return mMessenger.getBinder();
}
class IncomingHandler extends Handler { // Handler of incoming messages from clients.
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_REGISTER_CLIENT:
mClients.add(msg.replyTo);
break;
case MSG_UNREGISTER_CLIENT:
mClients.remove(msg.replyTo);
break;
case MSG_SET_INT_VALUE:
switch (msg.arg1) {
case MSG_DO_UPDATE:
if (Constants.LOG_DEBUG) Log.d(TAG,"UI has asked to update");
update();
break;
}
break;
default:
super.handleMessage(msg);
}
}
}
private void sendMessageToUI() {
if (Constants.LOG_DEBUG) Log.d(TAG, "Notifying "+mClients.size()+" UI clients that an update was completed");
for (int i=mClients.size()-1; i>=0; i--) {
try {
// Send data as an Integer
mClients.get(i).send(Message.obtain(null, MSG_SET_INT_VALUE, MSG_DATA_UPDATED, 0));
} catch (RemoteException e) {
// The client is dead. Remove it from the list; we are going through the list from back to front so this is safe to do inside the loop.
mClients.remove(i);
}
}
}
public static boolean isRunning()
{
return isRunning;
}
#Override
public void onCreate() {
super.onCreate();
isRunning = true;
if (Constants.LOG_DEBUG) Log.d(TAG, "Service Started");
update();
}
#Override
public void onDestroy() {
if (Constants.LOG_DEBUG) Log.d(TAG, "Service Destroyed");
isRunning = false;
}
private void update() {
/**Your code to do an update goes here */
}
}

Yes, personally i think that the network and UI should be in separate threads. The way I tend to communicate between the two, which is probably not the recommended proper way, but it works for me, is to create a global variable in your application class. hope this helps a little

I would directly post to the main UI thread,
Handler mHandler = new Handler(Looper.getMainLooper());
mHandler.post(new Runnable() {...});