Using SL4A (Python) and bluetooth

Question

Looking for some pointers to get me started.

In my left hand I have a SGS2 running ICS. I've got SL4A up and running and have installed Python 2.6.2

In my right hand I've got a generic chinese bluetooth RFID reader. It works, it reads tags (it has a display) and it's paired with the phone.

I'd like them to play nicely - I want to script something that will keep watching the device and capture the codes as they are transmitted.

I'm no Python expert but I've been using it for some time now for building simple I/O jobs on web servers so I can just about find my way around.

Unusually though, I'm having real problems getting going with this - I can't find any 'getting started with Bluetooth and SL4A' resources to get over that first step of establishing a persistent connection and monitoring output.

Any tips?

Solution

it seems that what you need is the bluetooth facade. Here are some commands pertaining to bluetooth that might be helpful to you:

bluetoothAccept
bluetoothActiveConnections
bluetoothConnect
bluetoothDiscoveryCancel
bluetoothDiscoveryStart
bluetoothGetConnectedDeviceName
bluetoothGetLocalAddress
bluetoothGetLocalName
bluetoothGetRemoteDeviceName
bluetoothGetScanMode
bluetoothIsDiscovering
bluetoothMakeDiscoverable
bluetoothRead
bluetoothReadBinary
bluetoothReadLine
bluetoothReadReady
bluetoothSetLocalName
bluetoothStop
bluetoothWrite
bluetoothWriteBinary
checkBluetoothState
toggleBluetoothState

To call any of these commands you would do something like

import android
droid = android.Android()
#call your commands with droid.bluetoothcommand
droid.bluetoothDiscoveryStart()
#or
droid.toggleBluetoothState(True)

Here is an example of some bluetooth functions, it is included with SL4A, but I added the comments for clarity:

import android #for bluetooth functions
import time #for waiting

#get everything setup
droid = android.Android()

#turn on bluetooth
droid.toggleBluetoothState(True)

#ask user
droid.dialogCreateAlert('Be a server?')
droid.dialogSetPositiveButtonText('Yes')
droid.dialogSetNegativeButtonText('No')
droid.dialogShow()

#get user response to question
result = droid.dialogGetResponse()

#if the result is 'Yes' ('positive') then is_server is set to True
is_server = result.result['which'] == 'positive'

if is_server:
  #so if is_server is true make the device discoverable and accept the next connection
  droid.bluetoothMakeDiscoverable()
  droid.bluetoothAccept()
else:
  #attempts to connect to a device over bluetooth, the logic being that if the phone
  #is not receiving a connection then the user is attempting to connect to something
  droid.bluetoothConnect()


if is_server:
  result = droid.getInput('Chat', 'Enter a message').result #Gets a message to send 
  #via bluetooth
  if result is None:
    droid.exit() #exit if nothing is in the message
  droid.bluetoothWrite(result + '\n') #otherwise write the message

while True: #receives a message
  message = droid.bluetoothReadLine().result
  droid.dialogCreateAlert('Chat Received', message)
  droid.dialogSetPositiveButtonText('Ok')
  droid.dialogShow()
  droid.dialogGetResponse()
  result = droid.getInput('Chat', 'Enter a message').result
  if result is None:
    break
  droid.bluetoothWrite(result + '\n')

droid.exit()

Finally, for a full list of bluetooth commands, check out http://code.google.com/p/android-scripting/wiki/ApiReference and scroll down to the bluetooth facade. Best of luck!