How to connect and transfer data between two Bluetooth-equipped Devices using Rhomobile

Prerequisite:

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Two Bluetooth-enabled device with Bluetooth switched on manually to make the device visible to other devices.

Internal Functionality:

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Steps we need to follow to make communication between 2 devices using Bluetooth.

- Before creating the connection the two devices need to be paired.

- In order to pair the two devices a password has to be exchanged between the two devices.

- Then the Device 1 (Any one of the device) should open the server socket. That means, it should behave like a master in the communication

- Device 2 should open the client socket. That means, it behaves like a slave to the recently created server (the first device) in the communication.

- Once the Bluetooth pairing has occurred, data can be exchanged between the devices using Rhomobile BluetoothSession API.

How to create the Application:

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- Open Rhostudio

- Go to File- New - Project

- select Rhodes/Rhomobile Application

- Enter the Application name

- Right click on App

- select New -Rhodes Model

- Enter Model name and Model Attribute

- Click on Finish

Important:

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-Open build.yml(present inside root folder i.e project )

-Go to Capability-Add

-select Bluetooth

-press OK

For Android:

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Add <uses-permission android:name="android.permission.BLUETOOTH" /> to application manifest file.

(path:-Rhostudio installation folder\ruby\lib\ruby\gems\1.8\gems\rhodes-3.3.2\platform\android\Rhodes\AndroidManifest.xml)

Now write the following code inside a view page (lets say index.erb) present inside the model.

index.erb

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<form method="POST" action="<%=url_for(:action => 'onSend')%>" >

</form>

// Calls the controller method ConnectAsServer to connect as a server

function onConnectServer() {

$.get('/app/BluetoothChat/ConnectAsServer', {});

return false;

}

// Calls the controller method ConnectAsClient to connect as a client

function onConnectClient() {

$.get('/app/BluetoothChat/ConnectAsClient', {});

return false; } </script>

And Now write the following code inside the controller present inside the created Model.

Inside Controller:

---------------

$connected_device_name = nil //Stores the connected device Name

#Creates a Bluetooth session as a Server

#It opens a server socket and wait to listen for incoming connections

# When one connection is available it calls the create_session() to create the connection

def ConnectAsServer

#Check whether any device is conected or not

if $connected_device_name == nil

# Scan for other remote Bluetooth devices and on select of the device it Creates a Bluetooth session

# Returns OK or ERROR

Rho::BluetoothManager.create_session(Rho::BluetoothManager::ROLE_SERVER,

url_for(:action => :CreateSessionCallback) )

else

# Disconnects the currenly connected Device

DisconnectSession

end

#Creates a Bluetooth session as a client

def ConnectAsClient

if $connected_device_name == nil

#Creates the session

Rho::BluetoothManager.create_session(Rho::BluetoothManager::ROLE_CLIENT,

url_for(:action => :CreateSessionCallback) )

else

# Disconnects the currenly connected Device

DisconnectSession

end

def DisconnectSession

#Disconnect from the device.

#Returns OK or ERROR.

Rho::BluetoothSession.disconnect($connected_device_name)

$connected_device_name = nil

end

# Callback method called after the Bluetooth session is created or canceled

# Prameters received in the callback:

# 1.status : OK / ERROR / CANCEL

# 2.connected_device_name : The name of the device connected via Bluetooth.

def CreateSessionCallback

$connected_device_name = @params['connected_device_name']

if @params['status'] == Rho::BluetoothManager::OK

#Set the Bluetooth session callback to Transfer data to the connected devices

Rho::BluetoothSession.set_callback($connected_device_name, url_for(:action => :SessionCallback))

end

# Callback to the set_callback of BluetoothSession

# Parameters received in the callback:

# 1.connected_device_name : Name of connected device;

# 2.event_type : SESSION_INPUT_DATA_RECEIVED or ERROR or SESSION_DISCONNECT

def SessionCallback

eventType = @params['event_type']

if eventType == Rho::BluetoothSession::SESSION_INPUT_DATA_RECEIVED

# receive data from the connected device.

OnDataReceived

end

# This method receives the data from the connected device

def OnDataReceived

# Get the session status.

# Returns the size of the data received by the bluetooth connection or -1 if error or 0 if empty

while Rho::BluetoothSession.get_status($connected_device_name) > 0

# Read data from the connected device.

# Returns an array of bytes.

message = Rho::BluetoothSession.read_string($connected_device_name)

end

# This method sends the data to the connected device

def onSend

message = @params['message']

# Write data to the connected device.

Rho::BluetoothSession.write_string($connected_device_name, message)

end

Related Tags:
Rhomobile, Bluetooth

Author: Prangya Das

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