Source:
The OPs Working Solution:
Sending a File using Bluetooth OBEX Object Push Profile (OPP)
I am trying to use this source in order to test transfer with my app. I have also tried running with variants but the main issue I am getting is that Eclipse wants to initialize this line:
BluetoothDevice device;
to
BluetoothDevice device=null;
In which case then the app gives me an error upon running.
In another case with similar code it will flag a problem with the actual getAddress().
Am I missing something here? Is it because I need to setup a bluetooth connection previously?
Usually BluetoothDevice is available when you find a remote device,
Hence you should first use BluetoothAdapter to discover remotedevices then use the code to send data to the remotedevice.
you can find a great tutorial in this regard here: (http://www.developer.android.com/guide/topics/connectivity/bluetooth.html)
Related
I'm trying to connect my app to the RN42 module.
// Create a socket based on the application ID with a paired device
// Fetch the published UUIDs from the mbed and use the first one
bluetoothSocket = connectedDevice.createRfcommSocketToServiceRecord(connectedDevice.getUuids()[0].getUuid());
// Connect to the device
if (!bluetoothSocket.isConnected())
bluetoothSocket.connect();
// Create the input and output streams for sending/receiving messages
socketInput = bluetoothSocket.getInputStream();
socketOutput = bluetoothSocket.getOutputStream();
I've got these in the Android Manifest
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
<uses-permission android:name="android.permission.BLUETOOTH"/>
I'm getting this error when I call bluetoothSocket.connect().
Attempt to invoke virtual method 'void android.bluetooth.BluetoothSocket.connect()' on a null object reference
After calling this line
bluetoothSocket = connectedDevice.createRfcommSocketToServiceRecord(connectedDevice.getUuids()[0].getUuid());
I've inspected the variable bluetoothSocket using Android Studio and it's not null. It somehow becomes null when bluetoothSocket.connect() is called.
Is that the expected behaviour? What can I do to fix it? The RN42 module works fine as I've tested it with the RN Bluetooth Chat app on Play Store.
I'm on Android 5.1 on a Nexus 7 if that helps.
I've managed to sort the issue by removing my Bluetooth connectivity code and instead basing it around the Android Bluetooth Chat example. I don't know what the exact issue was but Bluetooth Chat example managed to fix it. Nothing obvious stands out so my best guess is, it was something subtle. If you are having a similar issue and connection between RN42 and Android is fiddly, create a sample Bluetooth Chat application and reuse that Bluetooth connectivity code.
Many less headaches! :)
Seethis reference guide for the module (p. 21) .
This might or might not apply to your case but is probably worth trying. They have special recommendations (default UUID and custom UUID respectively) for the module when connecting to Android devices.
Use the createInsecureRfcommSocketToServiceRecord instead. Insecure socket allows the RFCOMM to communicate with a non-authenticated paired device. Embedded devices like the RN42 or KC2114 have a difficult time performing authenticated pairing, because user interaction is required (numeric comparison, yes-no response). The "Just Works" automatic pairing will not produce an authenticated pairing. KC2114 supports both automatic authenticated pairing (with a small hack) and Just Works non-authenticated pairing.
Is there any way for Android to connect to a Bluetooth device using a specific port instead of using service UUID?
I know this option is available in other platforms which provide Bluetooth support (Java ME for example by specifying a "btspp://" style URL).
Thanks!
Ok, it's been a while, but I found a solution to the problem. I actually intended to give up and use UUID, but I kept getting a Service Discovery Failed (IO)exception, and when I tried to find a solution to the service discovery issue, I found the solution to my original question... Ain't life something?:)
Anyways, this is the link I stumbled upon, though you should note there is a mistake in the answer (they actually simply connected to port 1, instead of using a service UUID).
And after this short history lesson, here is the solution:
Using reflection, it is possible to create the Rfcomm socket connecting to a port number instead of UUID:
int bt_port_to_connect = 5; // just an example, could be any port number you wish
BluetoothDevice device = ... ; // get the bluetooth device (e.g., using bt discovery)
BluetoothSocket deviceSocket = null;
...
// IMPORTANT: we create a reference to the 'createInsecureRfcommSocket' method
// and not(!) to the 'createInsecureRfcommSocketToServiceRecord' (which is what the
// android SDK documentation publishes
Method m = device.getClass().getMethod("createInsecureRfcommSocket", new Class[] {int.class});
deviceSocket = (BluetoothSocket) m.invoke(device,bt_port_to_connect);
A few things to notice:
since we're using Invoke, the first parameter is the object we're invoking the method on, the second parameter of invoke is actually the first function parameter)
There is also a secure version available ('createRfcommSocket'), which accepts a bluetooth channel number as a single parameter (again, since this is invoke style, you'll need to pass the object to invoke the method on, as mentioned in -1- )
I found what appears to be a link to these functions' prototypes
Good luck to all.
Bluetooth Android connections are exclusively done via UUID. Each Bluetooth device has a UUID for every service it runs (see Bluetooth SDP).
You just give Android the UUID to watch for and, in client mode, it will find a socket to connect to automatically (including port). In server mode, it will wait for the specified device to initiate a connection using the specified UUID.
The BluetoothSocket object is also valid when connection is established (use getInput/Output Stream)
See Server Socket documentation and Client Socket documentation.
If you really want to check everything, you can see what Android decodes from the other device's SDP and the UUID you provided.
Use this tutorial to get the Bluetooth interface (very easy to do).
Then the code should look something like this:
IBluetooth ib =getIBluetooth();
Int otherDevicePort = ib.getRemoteServiceChannel(otherDeviceAddress, UUID);
I'm using bluecove which allow me to do so with the function Connector.open().
I use the following url:
btspp://" + phoneID + ":" + phonePort
N.b.: Some options can be added (e.g.: authenticate=false; or encrypt=false;).
With phoneID being the the being the Bluetooth address and phonePort the port number.
How to find the Bluetooth address?
From this link:
From the Home screen, open the app drawer, then open “Settings“.
Select “System“. (Skip this step on some models)
Scroll down to the bottom and tap “About Phone“, “About device“, or “About tablet“.
Scroll down to the bottom and tap “Status“.
Scroll down and the “Bluetooth address” will be shown in the list.
How to find the port number?
I haven't been able to find which port is supposed to be used yet...
I used 5 and it works but I need to research why and if I want to change the phone I will need to know if I also need to change the port.
Can anyone give me an idea on how to read the values from the OBD II Bluetooth adapter in an android application.
I want to start with scanning for the bluetooth devices from my android application, then after bluetooth device is found, how would I interact with it and get the values from it?
You should start by reading this http://developer.android.com/guide/topics/wireless/bluetooth.html
it contains step by step procedure .
add required permissions,
make a bt adapter,
then find paired/unpaired devices
I used the BluetoothChat Application and was able to get some basic communications, I am not moving into data logging. You can use this application to have a sort of instant messenger conversation with your ECM.
What particular dongle are you using?
Do you know what protocols are in use within your vehicle?
Download the BluetoothChat sample application -
They will have already handled the intricacies of the connection for you, you will have to change the UUID in order to connect with your device - 00001101-0000-1000-8000-00805F9B34FB
Read up on your particular dongle, some require the return character to be sentat the end of every command "\r"
This should get you started!
Once you have made the Bluetooth connection using the android bluetooth api, use the transport to send and receive data via the Bluetooth channel.
This is new developer resource document:
https://developer.android.com/guide/topics/connectivity/bluetooth.html
The general workflow of the application functionality should go like this:
1) connect to the OBDII adapter through Bluetooth;
2) initialize OBDII adapter with AT commands;
3) continuously get data from the vehicle through issuing the corresponding PID codes.
This article also may be helpful.
http://blog.lemberg.co.uk/how-guide-obdii-reader-app-development
I'm creating Bluetooth custom application, but I have a small issue. When in my receiver I detect a device, I want to store this device in Set<BluetoothDevice>.
But my receiver is a different class, and when I write this code:
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
ClassName.SetVar.add(device);
Then it is showing an exception. I want to store all detecting device in a variable and want to use in diffrent thread to establish a connection.
Finally i solved by using a constructor
Currently Iam using backport.android.bluetooth2.jar file for bluetooth programming with Android 1.5.Whenever device pairing fails it populates alert dialog for passKey and if i give passkey then in my log iam getting below error
07-21 12:25:52.419: WARN/BluetoothDeviceService(948): setPin(00:0E:6D:BA:89:F3) called but no native data available, ignoring. Maybe the PasskeyAgent Request was cancelled by the remote device or by bluez.
For successfully pair my BT device I always rebooting my tablet and manually pair the device with Settings options.So at last i realised to give this passKey programmatically but i haven't found any method for this.But in google opensource i found one method that is commented with #hide setPassKey(String Address,int passKey) in BluetoothDevice.java of backport.android.bluetooth2.jar .This will n't appear in my jar file.If any way is there for pairing the unbounded device please give reply ASAP?
In the AndroidBluetoothAPI_0.3.jar file following methods are available i,e: pair(address) and setPin() for setting the pin programmatically and connecting the BT device.For finding the signal strength method is available in this api.Below is the code project link
http://code.google.com/p/android-bluetooth/downloads/detail?name=AndroidBluetoothAPI_0.3.jar&can=2&q=