Я написал подобные приложения, и я предпочитаю метод Handler. На самом деле я написал класс Abstract Activity, чтобы выполнить всю тяжелую работу и просто расширить его в любой деятельности, которая хочет получать уведомления об изменениях.
Чтобы использовать следующий код, просто получите действие, чтобы расширить UpdatableActivity и переопределить метод dataUpdated (). Этот метод вызывается, когда ваша служба уведомляет обработчик об обновлении данных. В коде службы введите свой код для обновления в методе update () (или измените его для вызова существующего кода). Это позволяет деятельности вызывать this.updateService () для принудительного обновления. Служба может вызвать метод sendMessageToUI (), чтобы уведомить все заинтересованные действия об обновлении данных.
Вот как выглядит абстрактная деятельность:
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);
}
}
}
А вот как выглядит сервис:
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 */
}
}