Develop Reference

Programmatically Auto Accept Incoming Bluetooth Files

I am trying to find a way to have a tablet basically auto-accept/give permission to accept an incoming Bluetooth Share file transferred from a laptop to my Nexus Android device. Since the Android bluetooth system itself does not support this feature, I was wondering if this could be done programmatically using an Android application that listened for the notification and accepted it for me.

MUCH EASIER WAY
If you have a rooted device and use XPosed Framework, your goal can be achieved much easier.
You Need not implement your own bluetooth server nor kill the original BT service, which are very bothering!!!
xposed tutorial link.
Try this code.
import android.util.*;
import de.robv.android.xposed.*;
import de.robv.android.xposed.callbacks.XC_LoadPackage.*;
import static de.robv.android.xposed.XposedHelpers.findAndHookMethod;
public class Tutorial implements IXposedHookLoadPackage
{
private String TAG="TUTORIAL";
public void handleLoadPackage(final LoadPackageParam lpparam) throws Throwable {
if (!lpparam.packageName.equals("com.android.bluetooth"))
{
Log.i(TAG,"Not: "+lpparam.packageName);
return;
}
Log.i(TAG,"Yes "+lpparam.packageName);
findAndHookMethod("com.android.bluetooth.opp.BluetoothOppManager", lpparam.classLoader, "isWhitelisted", String.class,new XC_MethodHook() {
#Override
protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
Log.v(TAG,"HOOK DONE");
param.setResult(true); /* you can compare the sender address(String) with your computer and determine if you return true or just allow the original method to be called after this returns.*/
}
});
}
}
I tested and it works fine:)
Links
Dropbox link of the auto accepting app
Dropbox link of the project files (zip)
Xposed apk site
Towelroot site to root your phone
Background(Original answer)
As I commented above, you bay be able to, and I tried and succeeded in blocking (though not receiving) with this code.
import android.util.*;
import de.robv.android.xposed.*;
import de.robv.android.xposed.callbacks.XC_LoadPackage.*;
import java.io.*;
import static de.robv.android.xposed.XposedHelpers.findAndHookMethod;
public class Tutorial implements IXposedHookLoadPackage
{
private String TAG="TUTORIAL";
public void handleLoadPackage(final LoadPackageParam lpparam) throws Throwable {
if (!lpparam.packageName.equals("com.android.bluetooth"))
{
Log.i(TAG,"Not: "+lpparam.packageName);
return;
}
Log.i(TAG,"Yes "+lpparam.packageName);
findAndHookMethod("com.android.bluetooth.opp.BluetoothOppService", lpparam.classLoader, "startSocketListener", new XC_MethodHook() {
#Override
protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
Log.v(TAG,"HOOK DONE");
param.setResult(null);
}
});
}
}
The code above hooks the method startListenerSocket() of com.android.bluetooth.BluetoothOppService and prevents the original method from being called by the line param.setResult(null);
Refer to here to see the full code of com.android.bluetooth.BluetoothOppService.java and you will understand the operation.
And the code you can start from is shown below.
import android.util.*;
import de.robv.android.xposed.*;
import de.robv.android.xposed.callbacks.XC_LoadPackage.*;
import static de.robv.android.xposed.XposedHelpers.findAndHookMethod;
public class Tutorial implements IXposedHookLoadPackage
{
private String TAG="TUTORIAL";
public void handleLoadPackage(final LoadPackageParam lpparam) throws Throwable {
if (!lpparam.packageName.equals("com.android.bluetooth"))
{
Log.i(TAG,"Not: "+lpparam.packageName);
return;
}
Log.i(TAG,"Yes "+lpparam.packageName);
findAndHookMethod("com.android.bluetooth.opp.BluetoothOppObexServerSession", lpparam.classLoader, "onPut", new XC_MethodHook() {
#Override
protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
Log.v(TAG,"HOOK DONE");
Class c=param.thisObject.getClass();
}
});
}
}
This code hooks the onPut method of com.android.bluetooth. BluetoothOppObexServerSession linked here. I either am newbie to xposed framework but I hope my answer helped.
I had the same issues you asked and partially solved the problem by implementing my custom OBEX server and manually / programmatically(with ps|grep and su kill pid) killing the native BluetoothOppService. But I will either try the idea of hooking and directly executing my code.
And to help you customize OBEX server session I post my implementation below.
#Override
public int onPut(Operation op)
{
if (D)
{
Log.d(TAG, "onPut " + op.toString());
}
HeaderSet request;
String name, mimeType;
Long length;
String extension=null;// type;
int obexResponse = ResponseCodes.OBEX_HTTP_OK;
String destination;
if (mTransport instanceof BluetoothObexTransport)
{
destination = ((BluetoothObexTransport) mTransport).getRemoteAddress();
}
else
{
destination = "FF:FF:FF:00:00:00";
}
boolean isWhitelisted =IsWhitelisted(destination);
try
{
boolean preReject = false;
request = op.getReceivedHeader();
if (V)
{
// Constants.logHeader(request);
}
name = (String) request.getHeader(HeaderSet.NAME);
length = (Long) request.getHeader(HeaderSet.LENGTH);
mimeType = (String) request.getHeader(HeaderSet.TYPE);
if (length == 0)
{
if (D)
{
Log.w(TAG, "length is 0, reject the transfer");
}
preReject = true;
obexResponse = ResponseCodes.OBEX_HTTP_LENGTH_REQUIRED;
}
if (name == null || name.isEmpty())
{
if (D)
{
Log.w(TAG, "name is null or empty, reject the transfer");
}
preReject = true;
obexResponse = ResponseCodes.OBEX_HTTP_BAD_REQUEST;
}
int dotIndex = name.lastIndexOf(".");
if (dotIndex > 0)
{
extension = name.substring(dotIndex + 1).toLowerCase();
}
// Reject policy: anything outside the "white list" plus unspecified
// MIME Types. Also reject everything in the "black list".
// if (!preReject && (mimeType == null || (!isWhitelisted && !Constants.mimeTypeMatches(
// mimeType, Constants.ACCEPTABLE_SHARE_INBOUND_TYPES))
// || Constants.mimeTypeMatches(mimeType,
// Constants.UNACCEPTABLE_SHARE_INBOUND_TYPES))) {
// if (D) {
// Log.w(TAG, "mimeType is null or in unacceptable list, reject the transfer");
// }
// preReject = true;
// obexResponse = ResponseCodes.OBEX_HTTP_UNSUPPORTED_TYPE;
// }
if (preReject && obexResponse != ResponseCodes.OBEX_HTTP_OK)
{
// some bad implemented client won't send disconnect
return obexResponse;
}
}
catch (IOException e)
{
Log.e(TAG, "get getReceivedHeaders error " + e);
return ResponseCodes.OBEX_HTTP_BAD_REQUEST;
}
int status = receiveFile(destination, name, extension, length, op);
/*
* TODO map status to obex response code
*/
if (status != BluetoothShare.STATUS_SUCCESS)
{
obexResponse = ResponseCodes.OBEX_HTTP_INTERNAL_ERROR;
}
Log.d(TAG, "MIME TYPE)" + mimeType);
return obexResponse;
}
I just removed some rejecting codes from the original one.
Also to look at my full code please refer to my git repository.
I also thank the contributors to the android project!

Android BLE characteristics getValue returns null

I am trying to write text data to my BLE device. So , i am following Android Bluetooth GATT classes to do the task. But i found writing the text to the Characteristics is fine but while trying to retrieve the Characteristics value , it returns null.
MyCode :
public void writeCharacteristic(BluetoothGattCharacteristic characteristic,
String text) {
String TAGS ="MyBeacon";
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAGS, "BluetoothAdapter not initialized");
return;
} else {
Log.w(TAGS, "Writting ... ");
}
byte[] data = hexStringToByteArray(text);
Log.w(TAGS, "Writting text = " + data);
try {
characteristic.setValue(URLEncoder.encode(text, "utf-8"));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
boolean writeValue = mBluetoothGatt.writeCharacteristic(characteristic);
Log.w(TAGS, "Writting Status = " + writeValue);
}
// Successfully onCharacteristicWrite also gets called //
#Override
public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
super.onCharacteristicWrite(gatt, characteristic, status);
String TAGS ="MyBeacon";
String text = null;
try {
text = new String(characteristic.getValue(), "UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
Log.w(TAGS, "onCharacteristicWrite = " + text+" :: "+status);
}
but while trying to read the Characteristics it returns null.
for (BluetoothGattCharacteristic gattCharacteristic : gattCharacteristics) {
final byte[] data = gattCharacteristic.getValue(); // returns null
if (data != null && data.length > 0) {
Log.d("MyBeacon", " Read Data ")
} else {
Log.d("MyBeacon", " Data is null")
}
}
MyBeacon
Also check the issue in other thread too.
Please help me out , suggest me some solution to write and read data successfully to my Beacon.

Syntax should be as follows,
mBluetoothGatt.readCharacteristic(characteristic);
Reading characteristics:
You can read the characteristic using mBluetoothGatt.readCharacteristic(characteristic);
You can have to read the characteristic's descriptor as follows,
mBluetoothGatt.readDescriptor(ccc);
Once you read it, it should return data by calling the onDescriptorRead callback.
Here you can set up (subscribe) to the charactersitic through either notification or indication by calling:
mBluetoothGatt.setCharacteristicNotification(characteristic, true)
once it returns true you will need to write to the descriptor again (the value of notification or indication)
BluetoothGattDescriptor clientConfig = characteristic.getDescriptor(CCC);
clientConfig.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
//clientConfig.setValue(BluetoothGattDescriptor.ENABLE_INDICATION_VALUE);
mBluetoothGatt.writeDescriptor(clientConfig);
Once this is done you will get notifications through onCharacteristicChanged callback every time the characteristic changes.
Do update me , if you have any problems while implementing,

I faced a similar issue where the characteristic.getValue returns Null. I was following exactly what is mentioned in the BLE Gatt documentation, and other blogs, but still the issue persisted until finally I understood what I was doing wrong.
At client device end, we setValue into the characteristic that we are interested in using
gatt.WriteCharacteristic(characteristic.setValue("Hello"));
At Server end, the request is received onto the onCharacteristicWriteRequest(....) callback.
Generally we expect the value that we set at client end to be carried by the characteristic parameter but we observe the characteristic.getValue() is null.
Where in the same callback we also have another parameter by name "Value" which actually carries the characteristic value we set at Client end. Please refer this parameter and this should solve the problem.

Did you read it too early? It should be read after onCharacteristicWrite() has been called.

Android AllJoyn: Connection with second machine gives error of BusAttachement

I have developed application for two different sensors. They are working fine separately but when I try to use them togather and create two diffent buses than Alljoyn gives this exception.
org.alljoyn.services.common.BusAlreadyExistException: The object has
been set previously with a BusAttachment.
Below is my source code for connection. Can anyone tell me why I'm having this issue.
private void connect()
{ org.alljoyn.bus.alljoyn.DaemonInit.PrepareDaemon(getApplicationContext());
bus = new BusAttachment("ControlPanelBrowser", BusAttachment.RemoteMessage.Receive);
bus.registerBusListener(new BusListener());
Status status = bus.registerBusObject(mControlPanelSignalInterface, Constants.SERVICE_PATH);
if (status != Status.OK) {
Log.d(TAG, "Problem while registering bus object");
}
SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
srpPassword = settings.getString(PREFS_PASSWORD, DEFAULT_SECURED_SRP_PASSWORD);
SrpAnonymousKeyListener authListener = new SrpAnonymousKeyListener(this, logger, AUTH_MECHANISMS);
Status authStatus = bus.registerAuthListener(authListener.getAuthMechanismsAsString(),
authListener, getKeyStoreFileName());
if ( authStatus != Status.OK ) {
Log.e(TAG, "Failed to register AuthListener");
}
status = bus.connect();
if (Status.OK == status){
String daemonName = Constants.DAEMON_NAME_PREFIX + ".ControlPanelBrowser.G" +
bus.getGlobalGUIDString();
int flag = BusAttachment.ALLJOYN_REQUESTNAME_FLAG_DO_NOT_QUEUE;
Status reqStatus = bus.requestName(daemonName, flag);
if (reqStatus == Status.OK) {
Status adStatus = bus.advertiseName(Constants.DAEMON_QUIET_PREFIX +
daemonName, SessionOpts.TRANSPORT_ANY);
if (adStatus != Status.OK){
bus.releaseName(daemonName);
Log.e(TAG, "Failed to advertise daemon name: '" + daemonName + "', Error: '" + status + "'");
}
else{
Log.d(TAG, "Succefully advertised daemon name: '" + daemonName + "'");
}
}
else {
Log.e(TAG, "Failed to request daemon name: '" + daemonName + "', Error: '" + status + "'");
}
}
status = bus.registerSignalHandlers(mControlPanelSignalInterface);
if (status != Status.OK) {
Log.d(TAG, "Problem while registering signal handlers");
}
// Initialize AboutService
aboutClient = AboutServiceImpl.getInstance();
aboutClient.setLogger(logger);
try {
aboutClient.startAboutClient(bus);
for (String iface : ANNOUNCE_IFACES) {
aboutClient.addAnnouncementHandler(this, new String[] {iface});
}
} catch (Exception e) {
logger.error(TAG, "Unable to start AboutService, Error: " + e.getMessage());
}
}

use registerBusObject twince and then you can make one signle bus attachment

why dont you create two Interfaces, one interface for one sensor respectively. then add these two interfaces in a class which implements these two interfaces and the busObject and register an implemntation of this class as a BusObject.
For example
Sensor1_interface.java and Sensor2_interface.java //are my two interface classes
create a new class Sensor_InterfaceList which inplements the two interfaces and the BusObject
class Sensor_InterfaceList implements Sensor1_interface,Sensor2_interface,BusObject
{
// implment your interfaces here
.....
}
private Sensor_InterfaceList mySensor_InterfaceList;
mySensor_InterfaceList = new Sensor_InterfaceList();
myBus.registerBusObject(mySensor_InterfaceList,"/your/path");
This should solve your problem :)

Connecting to existing Google Chromecast Session from Android (for generic remote control)

I am creating a generic Chromecast remote control app. Most of the guts of the app are already created and I've managed to get Chromecast volume control working (by connecting to a Chromecast device along side another app that is casting - YouTube for example).
What I've having difficult with is performing other media commands such as play, pause, seek, etc.
Use case example:
1. User opens YouTube on their android device and starts casting a video.
2. User opens my app and connects to the same Chromecast device.
3. Volume control from my app (works now)
4. Media control (play, pause, etc) (does not yet work)
I found the Cast api reference that explains that you can sendMessage(ApiClient, namespace, message) with media commands; however the "message" (JSON) requires the sessionId of the current application (Youtube in this case). I have tried the following, but the connection to the current application always fails; status.isSuccess() is always false:
Cast.CastApi
.joinApplication(mApiClient)
.setResultCallback(
new ResultCallback<Cast.ApplicationConnectionResult>() {
#Override
public void onResult(
Cast.ApplicationConnectionResult result) {
Status status = result.getStatus();
if (status.isSuccess()) {
ApplicationMetadata applicationMetadata = result
.getApplicationMetadata();
sessionId = result.getSessionId();
String applicationStatus = result
.getApplicationStatus();
boolean wasLaunched = result
.getWasLaunched();
Log.i(TAG,
"Joined Application with sessionId: "
+ sessionId
+ " Application Status: "
+ applicationStatus);
} else {
// teardown();
Log.e(TAG,
"Could not join application: "
+ status.toString());
}
}
});
Is is possible to get the sessionId of an already running cast application from a generic remote control app (like the one I am creating)? If so, am I right in my assumption that I can then perform media commands on the connected Chromecast device using something like this:
JSONObject message = new JSONObject();
message.put("mediaSessionId", sessionId);
message.put("requestId", 9999);
message.put("type", "PAUSE");
Cast.CastApi.sendMessage(mApiClient,
"urn:x-cast:com.google.cast.media", message.toString());
Update:
I have tried the recommendations provided by #Ali Naddaf but unfortunately they are not working. After creating mRemoteMediaPlayer in onCreate, I also do requestStatus(mApiClient) in the onConnected callback (in the ConnectionCallbacks). When I try to .play(mApiClient) I get an IllegalStateException stating that there is no current media session. Also, I tried doing joinApplication and in the callback performed result.getSessionId; which returns null.

A few comments and answers:
You can get the sessionId from the callback of launchApplication or joinApplication; in the "onResult(result)", you can get the sessionId from: result.getSessionId()
YouTube is still not on the official SDK so YMMV, for apps using official SDK, you should be able to use the above approach (most of it)
Why are you trying to set up a message yourself? Why not building a RemoteMediaPlayer and using play/pause that is provided there? Whenever you are working with the media playback through the official channel, always use the RemoteMediaPlayer (don't forget to call requestStatus() on it after creating it).

Yes it is possible , First you have to save sesionId and CastDevice device id
and when remove app from background and again open app please check is there sessionId then call bello line.
Cast.CastApi.joinApplication(apiClient, APP_ID,sid).setResultCallback(connectionResultCallback);
if you get success result then need to implement further process in connectionResultCallback listener.
//Get selected device which you selected before
#Override
public void onRouteAdded(MediaRouter router, MediaRouter.RouteInfo route) {
// Log.d("Route Added", "onRouteAdded");
/* if (router.getRoutes().size() > 1)
Toast.makeText(homeScreenActivity, "'onRouteAdded :: " + router.getRoutes().size() + " -- " + router.getRoutes().get(1).isSelected(), Toast.LENGTH_SHORT).show();
else
Toast.makeText(homeScreenActivity, "'onRouteAdded :: " + router.getRoutes(), Toast.LENGTH_SHORT).show();*/
if (router != null && router.getRoutes() != null && router.getRoutes().size() > 1) {
// Show the button when a device is discovered.
// Toast.makeText(homeScreenActivity, "'onRouteAdded :: " + router.getRoutes().size() + " -- " + router.getRoutes().get(1).isSelected(), Toast.LENGTH_SHORT).show();
mMediaRouteButton.setVisibility(View.VISIBLE);
titleLayout.setVisibility(View.GONE);
castName.setVisibility(View.VISIBLE);
selectedDevice = CastDevice.getFromBundle(route.getExtras());
routeInfoArrayList = router.getRoutes();
titleLayout.setVisibility(View.GONE);
if (!isCastConnected) {
String deid = MyPref.getInstance(homeScreenActivity).readPrefs(MyPref.CAST_DEVICE_ID);
for (int i = 0; i < routeInfoArrayList.size(); i++) {
if (routeInfoArrayList.get(i).getExtras() != null && CastDevice.getFromBundle(routeInfoArrayList.get(i).getExtras()).getDeviceId().equalsIgnoreCase(deid)) {
selectedDevice = CastDevice.getFromBundle(routeInfoArrayList.get(i).getExtras());
routeInfoArrayList.get(i).select();
ReSelectedDevice(selectedDevice, routeInfoArrayList.get(i).getName());
break;
}
}
}
}
}
//Reconnect google Api Client
public void reConnectGoogleApiClient() {
if (apiClient == null) {
Cast.CastOptions apiOptions = new
Cast.CastOptions.Builder(selectedDevice, castClientListener).build();
apiClient = new GoogleApiClient.Builder(this)
.addApi(Cast.API, apiOptions)
.addConnectionCallbacks(reconnectionCallback)
.addOnConnectionFailedListener(connectionFailedListener)
.build();
apiClient.connect();
}
}
// join Application
private final GoogleApiClient.ConnectionCallbacks reconnectionCallback = new GoogleApiClient.ConnectionCallbacks() {
#Override
public void onConnected(Bundle bundle) {
// Toast.makeText(homeScreenActivity, "" + isDeviceSelected(), Toast.LENGTH_SHORT).show();
try {
String sid = MyPref.getInstance(homeScreenActivity).readPrefs(MyPref.CAST_SESSION_ID);
String deid = MyPref.getInstance(homeScreenActivity).readPrefs(MyPref.CAST_DEVICE_ID);
if (sid != null && deid != null && sid.length() > 0 && deid.length() > 0)
Cast.CastApi.joinApplication(apiClient, APP_ID, sid).setResultCallback(connectionResultCallback);
isApiConnected = true;
} catch (Exception e) {
}
}
#Override
public void onConnectionSuspended(int i) {
isCastConnected = false;
isApiConnected = false;
}
};

Google Cast SDK - getting a network timeout a few seconds after opening a session

This is my openSession method, based on the sample's:
Log.d("asdf", "Beginning session with context: " + mCastContext);
Log.d("asdf", "The session to begin: " + mSession);
mSession.setListener(new com.google.cast.ApplicationSession.Listener() {
#Override
public void onSessionStarted(ApplicationMetadata appMetadata) {
Log.d("asdf", "Getting channel after session start");
ApplicationChannel channel = mSession.getChannel();
if (channel == null) {
Log.e("asdf", "channel = null");
return;
}
Log.d("asdf", "Creating and attaching Message Stream");
mMessageStream = new MediaProtocolMessageStream();
channel.attachMessageStream(mMessageStream);
if (mMessageStream.getPlayerState() == null) {
if (mMedia != null) {
loadMedia(mMedia);
}
} else {
Log.d("asdf", "Found player already running");
// updateStatus(); TODO
}
}
It works fine, and I can push content to Leapcast (emulator) in a short window of time, usually about 6 seconds.
After that 6 seconds, however, I get this:
Log: onEnded failed to connect channel: network I/O timeout
Called from onSessionEnded.
What exactly is ending my session? Is it just an issue with Leapcast? Do I need to do some sort of keep-alive?