@Override
protected Object doInBackground(Object... params) {
log("create connection");
String mqttConnSpec = "tcp://" + brokerHostName + "@" + MQTT_BROKER_PORT_NUM;
// Create the client and connect
try {
mqttClient = MqttClient.createMqttClient(mqttConnSpec, MQTT_PERSISTENCE);
String clientID = MQTT_CLIENT_ID + "/" + mPrefs.getString(PREF_DEVICE_ID, "");
mqttClient.connect(clientID, MQTT_CLEAN_START, MQTT_KEEP_ALIVE);
// register this client app has being able to receive messages
mqttClient.registerSimpleHandler(this);
// Subscribe to an initial topic, which is combination of client
// ID
// and device ID.
initTopic = MQTT_CLIENT_ID + "/" + initTopic;
subscribeToTopic(initTopic);
} catch (MqttException e) {
e.printStackTrace();
}
log("Connection established to " + brokerHostName + " on topic " + initTopic);
// Save start time
mStartTime = System.currentTimeMillis();
// Star the keep-alives
startKeepAlives();
return null;
}
private synchronized void keepAlive() {
try {
// Send a keep alive, if there is a connection.
if (mStarted == true && mConnection != null) {
mConnection.sendKeepAlive();
}
} catch (MqttException e) {
log("MqttException: " + (e.getMessage() != null ? e.getMessage() : "NULL"), e);
mConnection.disconnect();
mConnection = null;
cancelReconnect();
}
}
private synchronized void connect() {
log("Connecting...");
// fetch the device ID from the preferences.
String deviceID = mPrefs.getString(PREF_DEVICE_ID, null);
// Create a new connection only if the device id is not NULL
if (deviceID == null) {
log("Device ID not found.");
} else {
try {
mConnection = new MQTTConnection(MQTT_HOST, deviceID);
} catch (MqttException e) {
// Schedule a reconnect, if we failed to connect
log("MqttException: " + (e.getMessage() != null ? e.getMessage() : "NULL"));
if (isNetworkAvailable()) {
scheduleReconnect(mStartTime);
}
}
setStarted(true);
}
}