B4A Library MQTT - MQ Telemetry Transport for B4A

This library was made based on MQTT Protocol


Installation instructions:
- Copy the .xml and .jar(s) files to your custom libraries folder
- Select in your REFERENCED LIBRARIES

Version history:
V1.0.0 (First public release - Donationware):
- Initial version

V1.0.2 (Release - Donationware):
- Implement method to get independence of threads

V1.0.4 (Release - Donationware):
- Implement method to subscribe a topic with QoS

V1.0.5 (Release - Donationware):
- Now can be used isConnected method "BEFORE" the first connection

V1.0.6 (Release - Donationware):
- not published

V1.0.7 (Release - Donationware):
- New methods: Publish2, Subscribe3, Subscribe4
This new methods return the token, then after when arrived or publish the messages, you can compare

MQTT
Author: Alberto Iglesias - [email protected]
Version: 1.07

• MQTT
  Events:
  • connectionlost ( )
  • deliverycomplete (Token As String)
  • messageArrived (Topic As String, Message As String)
  • onConnect (Status as boolean As )
  • onDisconnect (Status as boolean As )
  • onInitialized ( )
  Fields:
  • CleanSession As Boolean
  • JavaDebug As Boolean
  • KeepAliveInterval As Int
  • QoS_AtLeastOnce As Int
  • QoS_AtMostOnce As Int
  • QoS_ExactlyOnce As Int
  • generatedClientId As String
  Methods:
  • About As String
  • Connect (broker As String, ClientID As String, Username As String, Password As String) As Boolean
  • Disconnect As Boolean
  • Initialize (eventname As String)
  • Publish (Topic As String, Message As String, Qos As Int, Retained As Boolean)
  • Publish2 (Topic AsString, Message AsString, Qos AsInt, Retained AsBoolean)
    
  • Subscribe (Topic As String)
  • Subscribe2 (Topic As String, QoS as int)
    
  • Subscribe3 (Topic As String)
    
  • Subscribe4 (Topic As String, QoS as int))
    
  • Unsubscribe (Topic As String)
  • Version As String
  • isConnected As Boolean
  Permissions:
  • android.permission.ACCESS_WIFI_STATE
  • android.permission.INTERNET

How works the MQTT protocol

Communication Infrastructure

References:
http://mqtt.org/
http://public.dhe.ibm.com/software/dw/webservices/ws-mqtt/mqtt-v3r1.html
Mosquitto Broker: http://mosquitto.org/



* This version is fully functional, the only one difference is when publishing a message the text "Donationware" is delivery with your message.
Please consider a simple €10 donation and I send to you the Library without "Donationware" text in a publish method.

Already available in B4J too:
https://www.b4x.com/android/forum/threads/mqtt-mq-telemetry-transport-for-b4j.48184/

Already available in B4i too:
https://www.b4x.com/android/forum/threads/mqtt-mq-telemetry-transport-for-b4i.50036/

 

[woniol]

Hi, I'm very interested in this lib.
Do You think i can work with B4J?

 

[Alberto Iglesias]

For B4J look in

https://www.b4x.com/android/forum/threads/mqtt-mq-telemetry-transport-for-b4j.48184/

Version this MQTT Library for B4J

 

[bluedude]

This is awesome, now need to find a stable hosted MQTT broker.

 

[woniol]

Works very well with Mosquitto.
I have one installed on my Rasperry pi
Here's the istalation manual:
http://jpmens.net/2013/09/01/installing-mosquitto-on-a-raspberry-pi/

 

[Alberto Iglesias]

Yes, the Mosquitto Broker is used by huge companies and works very well and stable, recommended by IBM.

http://projects.eclipse.org/projects/technology.mosquitto

And another one from IBM is RSMB (Really Small Message Broker)

Avaiable for download in https://www14.software.ibm.com/webapp/iwm/web/reg/pick.do?source=swg-rlsmmsbk&lang=en_US

 

[alwaysbusy]

Thanks for the lib Alberto! Can this be used to send messages from one android device to another? And is there a limit to the length of the message you are sending?

 

[little3399]

Hi,

Does this Lib can be transplant to B4i ?

 

[Alberto Iglesias]

Hi..

The MQTT protocol says:

" The length is limited to 64k but within that there are no limits to the number of levels in a topic tree.

• There can be any number of root nodes; that is, there can be any number of topic trees."

But the MQTT was constructed to be lightweight, to be fast!


I think works, but you can try...



And for B4i, YES, I think in construct a library in January, because in this holydays I can´t :-( Sorry.....


Thanks!

 

[Alberto Iglesias]

A Free broker to test with you aplication:

URL: broker.mqtt-dashboard.com
Port: 1883

 

[bluedude]

Interesting and works like a breeze. I have a broker running on CentOS VPS and it was only a few minutes work.

The B4A sample seems to have some threading problems, I cannot intercept the message and bind it to a view. Any suggestions?

Should I put the sample in a service?

 

[Alberto Iglesias]

Hello bluedude,

what type of threading problems? You try use another library? This wrapper is based on PAHO library, and this library not intercept any message.


Tks!

 

[bluedude]

In objMqtt_messageArrived(Topic As String, Message As String)

i'm trying to put the received Message in an edittext on the layout, this is not allowed and i'm getting an error about main threads. Logging it works fine but for the rest I cannot do anything.

I'm not using any other libraries just your stuff.

 

[Alberto Iglesias]

I see... Look this example with thread and EDITTEXT.

I think this is resolve your problem.


I put this free broker in this sample

tcp://broker.mqtt-dashboard.com:1883

you can follow the messages in
Dashboard: http://mqttdashboard.com/dashboard

Best regards!

 

[Alberto Iglesias]

hey bluedude, I implement new method in library to works independent of thread Library.

Version 1.0.2 available with another sample (MQTTSampleActivity.zip)

 

[bluedude]

Works great but what i'm missing is a Quality of Service flag in the subscribe method. I see you have it in publish but not in subscribe.

 

[Alberto Iglesias]

You right bluedude!

I put in this new version (1.0.4) and available for download.

I upload to a sample with subscribe2 method.

Thanks!

 

[bluedude]

Great, I will make a donation a.s.a.p. MQTT is a huge benefit over Google Cloud Messaging which sucks in my opinion. JSON over MQTT is perfect for many scenario's, instead of polling for new data a server can update clients through topics which is much better.

 

[Aidan Ruff]

Hola Alberto
I just sent you 10 euros - nice work, thanks. If you get a chance to send me the full version without the added text, I'd appreciate it!

 

[Alberto Iglesias]

Hello Aidan,

I sent to you in your email, check please!

Thanks!