I am creating an Android app - one feature of this app is that if the user connects to a BLE device and clicks a button, the app will remember the device and automatically connect in future. From what I understand, this means I need bonding.
I came across the createBond() method, but realised that it is only usable in API 19 (Android 4.4) and onwards. The person I am making this for would much prefer it be available in API 18 (Android 4.3) as the product has already been advertised as such.
Assuming that I am correct in my approach (meaning, through active use of Bonding - I'm self-teaching Bluetooth, so please correct me if this isn't the way to go or if I am misunderstanding), is there any way that I can achieve what I want to without createBond()? If so, how? Or is API19 something we will have to live with?
One option is to use a preference in conjunction with your callback for device scanning.
Assuming you're using an LeScanCallback somewhere in your app:
BluetoothAdapter.LeScanCallback mCallBack =
new BluetoothAdapter.LeScanCallback() {
#Override
public void onLeScan(BluetoothDevice device, int rssi, byte[] scanRecord) {
// You can place this elsewhere so this isn't called for every device
String storedAddr = myContext.getSharedPreferences("global", Context.MODE_PRIVATE).getString("storedAddr","");
if(storedAddr.equals("")) {
// Do your normal process to list / connect to devices.
// Store device.getAddress() in preferences once connected.
} else if(device.getAddress().equals(storedAddr) {
// Do whatever you want with the matching device
}
}
}
Of course, you'll have to deal with an option to remove that stored address so that they can choose a new device to save, if needed.
Related
I'm trying to implement the application which will communicate with BLE findme device. I have the one of these devices, but have some problem with it. Using iPhone I have tested this device with bleTools application and this app works correctly, i.e. I have managed to read all device's characterictics and send the characteristics to make the device beep. But using Android (Nexus 5) I could only read the device's characteristics, but cannot make the device beep.
My code is:
private static final UUID IMMEDIATE_ALERT_SERVICE =
UUID.fromString("00001802-0000-1000-8000-00805f9b34fb");
private static final UUID IMMEDIATE_ALERT_LEVEL =
UUID.fromString("00002a06-0000-1000-8000-00805f9b34fb");
...
public void beep(DeviceData device) {
BluetoothGatt gatt = mConnectedDevices.get(device.getDeviceAddress());
BluetoothGattService bluetoothGattService = gatt.getService(IMMEDIATE_ALERT_SERVICE);
if (bluetoothGattService == null) {
return;
}
BluetoothGattCharacteristic characteristic =
bluetoothGattService.getCharacteristic(IMMEDIATE_ALERT_LEVEL);
if (characteristic == null) {
return;
}
byte[] arrayOfByte = new byte[1];
arrayOfByte[0] = (byte) 0x01;
characteristic.setValue(arrayOfByte);
gatt.writeCharacteristic(characteristic);
}
The callback method returns Ok:
#Override
public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
if (characteristic.getUuid().toString().equals(IMMEDIATE_ALERT_LEVEL.toString())) {
//TODO: use device address to identify the device-receiver
Message msg = new Message();
msg.what = MSG_PARAM_WRITTEN;
msg.obj = (status == BluetoothGatt.GATT_SUCCESS);
mHandler.sendMessage(msg);
}
}
but nothing happens on the device side.
Can anyone explain me what I'm doing wrong or maybe give some advice what should I do?
And again, I can read the device characteristics, but cannot write them to the device.
Unlike iOS, Android has quite a few undocumented tricks with Bluetooth. I'm assuming you are using the standard Bluetooth library included in Android 4.3 and later. If you using other libraries like Samsung or Broadcom, the results could be different.
Because I do not have a findeme device I cannot confirm anything. But I have worked with both classic and low energy Bluetooth energy on Android for a while now. My advice is to go through the complete process of scan, discover services and read/write characteristics.
startLeScan
onLeScanCallBack connect to the device
onConnect discoverServices
onServicesDiscovered get all characteristics
check the properties on each characteristic
if you can read it, go ahead and do that
after that is done, you can then write the characteristic and listen for the onCharacteristicWrite event. You may get the beep then. If not, you'll need to go back to the iOS project and trace every bit that is sent to and received from the findme device. That sounds difficult but it's really just a matter of reading bytes inside of the right delegates. Document that. Then go back and recreate the bit sequence on the Android side. Again, capture all the traffic to and from the findme device. If you can get the bit sequence to match, you'll have success.
There's one more very important thing to know about Android BLE. The writes must be sequential. By that I mean, if you write a characteristic, you must wait for the onCharacteristic event to fire before you can write another one. This is not documented on the Android developer site. The best way to implement this functionality is to use a LinkedList as a work queue.
Good luck and ping me if you have questions.
I am trying to create a WI-FI Direct network with say 3 tablet PCs. I want to run WiFi-Direct as background service, with one device set as autonomous GO. Could someone please tell me how can this be done in Android? Also someone please tell me how we can set dedicated SSID and passphrase so that any time new devices are added to this network, they can search for a specific ssid and passphrase for connection establishment during the application initiation ?
I am using Android API Level 18 for my development ...
Thanks in advance ...
This is how an autonomous Group Owner is created i.e. using the following code you can deliberately set a device in Wifi direct Network as a Group Owner
manager.createGroup(channel,new WifiP2pManager.ActionListener()
{
#Override
public void onSuccess()
{
Toast.makeText(WiFiDirectActivity.this, "Group Created",Toast.LENGTH_SHORT).show();
}
#Override
public void onFailure(int reason)
{}
});
You can use this code on any event like Button click etc.
Bluemoon10 was almost right. I can't comment yet because I need 50 reputation :/. The config.groupOwnerIntent ranges from 1-15 with 15 being the highest intent to be group owner.
If 2 devices try to connect with both GO intents == 15, the connect call will fail. If there is a GO intent tie lower than 15, the devices agree on a tie breaker bit and will succeed. So if you want one device to be group owner, you have to make sure that it is the only one trying to be. You can do this with Service Discovery, i.e. if there is a service running set your GO intent to 15 on the device with the service and 1 on the connecting device. Only one device needs to call connect to initiate connection.
Link to Service Discovery tutorial: http://developer.android.com/training/connect-devices-wirelessly/nsd-wifi-direct.html
To create autonomous group you can just invoke createGroup() method from your manager. In order to set ssid and passPhrase you must invoke the hidden methods of WifiP2pGroup class setPassphrase and setNetworkName.
To achieve that, you use java reflection. Try the following example.
Let us assume WifiP2pGroup group your current object.
Method
setPassPhraseMethod=group.getClass().getMethod("setPassphrase", new Class[ {String.class});
and now you invoke the method:
setPassPhraseMethod.invoke(group, "yourNewPassPrhase");
hope it is helpful.
Normally the Group Owner is decided by the WiFi Direct protocol.
However you can force it's hand by, using the config class.
final WifiP2pConfig config = new WifiP2pConfig();
config.deviceAddress=myDeviceAddr;
config.wps.setup = WpsInfo.PBC;
config.groupOwnerIntent =15;
In this case I think I'm correct in saying that 15 mean least likely to become GO, you set this to zero, if you want that device to be the GO.
Also this might be where you can set pin etc take a look at WpsInfo.
this config info in then passed into your connect call.
mManager.connect(mChannel, config, new WifiP2pManager.ActionListener().
Hope this helps.
I am working on using the BT 4.0 API that Motorola has provided with the RAZR. In one of their documents it states to use the Android API to pair before connecting and using their framework. Per their instructions I have been pairing with OS Bluetooth settings application, but it never prompts me for a key. It will pair but doesn't appear to bond, and this is critical for me.
My question is, when they say "using the Android API" is this referring to simply using the OS Bluetooth utility to pair before hand (like I have been doing), or is there some way to do it with code in my application. They reference the "createBond()" function which, to my knowledge, is not an accessible function (at least not without some squirrely libraries or reflection).
Any advice is greatly appreciated, especially anyone who has used the API successfully, if they could give an account of their process. I'm just looking for some clarity at this point :)
Lloyd,
You are correct, follow the instructions in the link you posted.
Outside of coding, when they say use the standard android api for "non-le" operations, they mean go ahead and pair the ble device the same way you would any bluetooth classic devices inside android settings -> wireless & network -> bluetooth -> scan for devices.
If the device you are using is a motorola le compatible device the ble device will be paired but not connected.
Now, in the code, you can detect this paired device through the same method of
BluetoothAdapter.getDefaultAdapter().getBondedDevices()
To double check if your Android Phone is LE compatible, run this code:
public static boolean checkBLESupport() {
boolean deviceSupportsLE;
try {
#SuppressWarnings({ "unused", "rawtypes" })
Class object = Class.forName("android.server.BluetoothGattService");
deviceSupportsLE = true;
} catch (Exception e) {
deviceSupportsLE = false;
}
return deviceSupportsLE;
}
And to double check if the bluetooth device you paired is LE, when you are looping through the bonded devices.
Check the device with this code.
if (device.getBluetoothClass() == null) {
Log.i(TAG, "This device is BLE compatible");
b = true;
} else {
Log.i(TAG, "This device is not BLE");
b = false;
}
Now for establishing connection from your LE compatible phone to your LE compatible bluetooth device, follow the Gatt service instructions under the link you posted. http://developer.motorola.com/docs/bluetooth-low-energy-api/
Take note that under this example it is connecting to a bluetooth low energy heart rate monitor.
If you are not trying to connect to the heart rate monitor with LE heart rate profile, here is a link to another Motorola document that details creating your own LE Profile to use with the GATT framework. http://developer.motorola.com/docs/bluetooth-low-energy-gatt-framework-api/
If the instructions are not clear enough at any point in either of these documents, motorola offers sample android applications using the frameworks in those documents.
I guess motorola stack has BLE support. But what i feel is that it does not pair with the devices that require bonding though It does work some sensors. I have tried with a proximity sensor that require bonding. It never gets paired though the devices is discovered with Razr which even does not with S3.
There's a helpful video here.
Late to the game, but can confirm -
If your BLE Peripheral requires bonding, Moto X - and some other older Motorola devices - MUST be paired via Bluetooth Settings prior to programmatic connection via the Android GATT interface.
If you bond via the createBond method, or reading of an encrypted characteristic, your connection will be dropped typically in under 60 seconds, despite DDMS logs that show a good bond may be established.
I have an app where I am programmatically controlling Bluetooth pairing and unpairing. I can pair before connection and unpair afterwards. The reason I need to do this is specific to my application and not in the scope of my question.
Basically what I am doing is:
Get a reference ib to IBluetooth object as described in this answer
Register a BroadcastReceiver for android.bluetooth.device.action.PAIRING_REQUEST
Call ib.createBond(address)
Wait for BroadcastReceiver to trigger
Convert user pin into bytes with convertPinToBytes()
Call ib.setPin(address, pinBytes) from within BroadcastReceiver
Anyways, this approach works great, except for the fact that when I do the pairing, I get a notification in the Status bar requesting that the user enter a PIN to complete the pairing. But this is in fact unnecessary, because by the time the user sees this, my app has already used setPin(). I'd really like for that notification to either a) not appear at all, or b) be dismissed automatically somehow.
I realize this may not even be possible, but I thought I would ask in case someone has a creative idea.
Try setting the confirmation first in the PAIRING_REQUEST
BluetoothDevice device = intent.getParcelableExtra("android.bluetooth.device.extra.DEVICE");
device.getClass().getMethod("setPairingConfirmation", boolean.class).invoke(device, true);
device.getClass().getMethod("cancelPairingUserInput").invoke(device);
This worked for me between two Android devices using RFCOMM but I'm not entering any PINs
Since Android API 19 Google switched these Methods to public Methods, so there is no need for Reflection any more. :)
Do this in the PAIRING_REQUEST notification event:
BluetoothDevice localBluetoothDevice = (BluetoothDevice)intent.getParcelableExtra("android.bluetooth.device.extra.DEVICE");
Class localClass = localBluetoothDevice.getClass();
Class[] arrayOfClass = new Class[0];
localClass.getMethod("cancelPairingUserInput", arrayOfClass).invoke(paramBluetoothDevice, null)).booleanValue();
But you gotta tell me how did you pair your remote device without the user to enter Passkey/PIN? off course, you know the PIN for the remote device which is trying to pair to your device but how did you provide that PIN to the remote device.
Alright, I've got a bit of a weird question here. I'm working on an Android game where I'd like to be able to have Android phones detect the presence of each other.
The device searching for other players will know the bluetooth mac addresses of the other players' devices (from a game DB), however the devices will not be paired and the devices will not be in discoverable mode. Also, there will only be a handful of devices that could possibly be found - so it's not a big deal to scan through mac addresses.
I don't need to connect to the devices, I just need to be able to answer one simple question: is this device with this mac address nearby?
It is permissible to have a pairing dialog appear on the other user's screen...I don't care what the outcome of their choice is...I just need to know if their device is there.
Any help would be greatly appreciated!
This use-case may be a good fit for the recently released Nearby API. See the Nearby Messages developer overview
Nearby has its own runtime permission saving you from adding BLUETOOTH_ADMIN or similar to your manifest. It works across iOS and Android by utilizing multiple technologies (Classic Bluetooth, BLE, ultrasound). There's an option to use only the ultrasonic modem which reduces the range to about 5 feet.
I've included a partial example below, you can find a more complete sample on github
// Call this when the user clicks "find players" or similar
// In the ResultCallback you'll want to trigger the permission
// dialog
Nearby.Messages.getPermissionStatus(client)
.setResultCallback(new ResultCallback<Status>() {
public void onResult(Status status) {
// Request Nearby runtime permission if missing
// ... see github sample for details
// If you already have the Nearby permission,
// call publishAndSubscribe()
}
});
void publishAndSubscribe() {
// You can put whatever you want in the message up to a modest
// size limit (currently 100KB). Smaller will be faster, though.
Message msg = "your device identifier/MAC/etc.".getBytes();
Nearby.Messages.publish(googleApiClient, msg)
.setResultCallback(...);
MessageListener listener = new MessageListener() {
public void onFound(Message msg) {
Log.i(TAG, "You found another device " + new String(msg));
}
});
Nearby.Messages.subscribe(googleApiClient, listener)
.setResultCallback(...);
}
Disclaimer I work on the Nearby API