rework backend API for slow-start services

When a backend does not accept packets immediately after start() (i.e.
because it needs to connect to a server first), start() must return
false and the backend needs to call service.postPosterStarted() as soon
as it is ready to accept data.

src/AprsService.scala

@@ -84,6 +84,9 @@ class AprsService extends Service {
 		} else
 			showToast(getString(R.string.service_start).format(upd_int, upd_dist))
 
+		val callssid = prefs.getCallSsid()
+		ServiceNotifier.instance.start(this, callssid)
+
 		// the poster needs to be running before location updates come in
 		if (!running) {
 			running = true
@@ -91,21 +94,28 @@ class AprsService extends Service {
 
 			// register for outgoing message notifications
 			registerReceiver(msgNotifier, new IntentFilter(AprsService.MESSAGETX))
-		}
-
-		// continuous GPS tracking for single shot mode
-		val loc_info = locSource.start(singleShot)
-
-		val callssid = prefs.getCallSsid()
-		val message = "%s: %s".format(callssid, loc_info)
-		ServiceNotifier.instance.start(this, message)
+		} else
+			onPosterStarted()
 	}
 
 	def startPoster() {
 		if (poster != null)
 			poster.stop()
 		poster = AprsIsUploader.instanciateUploader(this, prefs)
-		poster.start()
+		if (poster.start())
+			onPosterStarted()
+	}
+
+	def onPosterStarted() {
+		Log.d(TAG, "onPosterStarted")
+		// (re)start location source, get location source name
+		val loc_info = locSource.start(singleShot)
+
+		val callssid = prefs.getCallSsid()
+		val message = "%s: %s".format(callssid, loc_info)
+		ServiceNotifier.instance.start(this, message)
+
+		msgService.sendPendingMessages()
 	}
 
 	override def onBind(i : Intent) : IBinder = null
@@ -226,6 +236,11 @@ class AprsService extends Service {
 	def postAbort(post : String) {
 		postAddPost(StorageDatabase.Post.TYPE_ERROR, R.string.post_error, post)
 	}
+	def postPosterStarted() {
+		handler.post {
+			onPosterStarted()
+		}
+	}
 
 }
 

src/MessageService.scala

@@ -12,9 +12,6 @@ class MessageService(s : AprsService) {
 	val NUM_OF_RETRIES = 7
 	val pendingSender = new Runnable() { override def run() { sendPendingMessages() } }
 
-	// lets start transmitting 30s after creation
-	scheduleNextSend(30*1000)
-
 	def createMessageNotifier() = new BroadcastReceiver() {
 		override def onReceive(ctx : Context, i : Intent) {
 			sendPendingMessages()

src/backend/AfskUploader.scala

@@ -12,8 +12,7 @@ class AfskUploader(prefs : PrefsWrapper) extends AprsIsUploader(prefs) {
 	var Digis = prefs.getString("digi_path", "WIDE1-1")
 	val output = new Afsk()
 	
-	def start() {
-	}
+	def start() = true
 
 	def update(packet : APRSPacket) : String = {
 		// Need to "parse" the packet in order to replace the Digipeaters

src/backend/AprsIsUploader.scala

@@ -59,7 +59,9 @@ object AprsIsUploader {
 abstract class AprsIsUploader(prefs : PrefsWrapper) {
 	val login = prefs.getLoginString()
 
-	def start()
+	// returns true if successfully started.
+	// when returning false, AprsService.postPosterStarted() must be called
+	def start() : Boolean
 
 	def update(packet : APRSPacket) : String
 

src/backend/BluetoothTnc.scala

@@ -21,9 +21,10 @@ class BluetoothTnc(service : AprsService, prefs : PrefsWrapper) extends AprsIsUp
 	var digipath = prefs.getString("digi_path", "WIDE1-1")
 	var conn : BtSocketThread = null
 
-	createConnection()
-
-	def start() {
+	def start() = {
+		if (conn == null)
+			createConnection()
+		false
 	}
 
 	def createConnection() {
@@ -107,6 +108,7 @@ class BluetoothTnc(service : AprsService, prefs : PrefsWrapper) extends AprsIsUp
 			} catch {
 				case e : Exception => e.printStackTrace(); service.postAbort(e.toString())
 			}
+			service.postPosterStarted()
 			while (running) {
 				try {
 					Log.d(TAG, "waiting for data...")

src/backend/HttpPostUploader.scala

@@ -12,8 +12,7 @@ class HttpPostUploader(prefs : PrefsWrapper) extends AprsIsUploader(prefs) {
 	val TAG = "APRSdroid.HttpPost"
 	val host = prefs.getString("http.server", "srvr.aprs-is.net")
 
-	def start() {
-	}
+	def start() = true
 
 	def doPost(urlString : String, content : String) : String = {
 		val client = new DefaultHttpClient()

src/backend/TcpUploader.scala

@@ -15,9 +15,10 @@ class TcpUploader(service : AprsService, prefs : PrefsWrapper) extends AprsIsUpl
 	val RECONNECT = 30
 	var conn : TcpSocketThread = null
 
-	createConnection()
-
-	def start() {
+	def start() = {
+		if (conn == null)
+			createConnection()
+		false
 	}
 
 	def setupFilter() : String = {
@@ -87,6 +88,7 @@ class TcpUploader(service : AprsService, prefs : PrefsWrapper) extends AprsIsUpl
 			} catch {
 				case e : Exception => service.postAbort(e.toString())
 			}
+			service.postPosterStarted()
 			while (running) {
 				try {
 					if (need_reconnect) {

src/backend/UdpUploader.scala

@@ -10,8 +10,7 @@ class UdpUploader(prefs : PrefsWrapper) extends AprsIsUploader(prefs) {
 	lazy val socket = new DatagramSocket()
 	val host = prefs.getString("udp.server", "srvr.aprs-is.net")
 
-	def start() {
-	}
+	def start() = true
 
 	def update(packet : APRSPacket) : String = {
 		val (h, port) = AprsPacket.parseHostPort(host, 8080)