Bluetooth: stuck at connect() - Android Q&A, Help & Troubleshooting

I'm programming a simple Bluetooth client to send and receive text messages throught RFCOMM as a serial port. I had a look at the Android SDK tutorials and did it in the same way: an Activity which calls a thread to make the connection, and once done, another thread to take care of msg reception.
I'm trying to connect to a Parallax EasyBluetooth. Connection works all right between computer and EasyBT, and also between a Java based mobile and the EasyBT. So the problem must be at the code or, I hope not, at the Android mobile bluetooth chip. Anyway it gets on and off, and detects other devices when scanning, so I guess problem is just my coding.
The problem is that the code gets stuck at the connect() method. So let's see if anyone knows why.
The XML for the activity is simple:
Code:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/boton"
android:id="@+id/boton_enviar"
/>
</LinearLayout>
Of course I have added the bluetooth permissions to the Manifiest:
Code:
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
And the code is the following:
Code:
package uniovi.PFC;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.UUID;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
public class PruebaBTActivity extends Activity {
private String TAG = "pruebaBT";
private BluetoothAdapter mBluetoothAdapter;
private Map<String, BluetoothDevice> mArrayAdapter;
private ConnectedThread hiloEscuchas;
private ConnectThread hiloConectando;
private Handler mHandler;
private Button botonEnviar;
private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
private static final int REQUEST_ENABLE_BT = 1;
private static final int MESSAGE_READ = 1;
private byte bytes_enviar[];
private String cmd;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Log.d(TAG, "On create abriendo");
mArrayAdapter = new HashMap<String, BluetoothDevice>();
botonEnviar = (Button)findViewById(R.id.boton_enviar);
botonEnviar.setEnabled(false);
botonEnviar.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
cmd = "A";
bytes_enviar = cmd.getBytes();
hiloEscuchas.write(bytes_enviar);
}
});
Log.d(TAG, "On create cerrando");
}
@Override
public void onResume() {
super.onResume();
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null) {
Log.d(TAG, "Device does not support Bluetooth");
}
if (!mBluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
// If there are paired devices
if (pairedDevices.size() > 0) {
// Loop through paired devices
for (BluetoothDevice device : pairedDevices) {
// Add the name and address to an array adapter to show in a ListView
mArrayAdapter.put(device.getName(), device);
}
}
BluetoothDevice device = mArrayAdapter.get("EasyBT");
hiloConectando = new ConnectThread(device);
hiloConectando.run();
//while(hiloEscuchas.isConnected()==false);
//botonEnviar.setEnabled(true);
}
private class ConnectThread extends Thread {
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
public ConnectThread(BluetoothDevice device) {
// Use a temporary object that is later assigned to mmSocket,
// because mmSocket is final
BluetoothSocket tmp = null;
mmDevice = device;
// Get a BluetoothSocket to connect with the given BluetoothDevice
try {
// MY_UUID is the app's UUID string, also used by the server code
tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) { }
mmSocket = tmp;
}
public void run() {
// Cancel discovery because it will slow down the connection
mBluetoothAdapter.cancelDiscovery();
try {
// Connect the device through the socket. This will block
// until it succeeds or throws an exception
mmSocket.connect();
} catch (IOException connectException) {
// Unable to connect; close the socket and get out
try {
mmSocket.close();
} catch (IOException closeException) { }
return;
}
// Do work to manage the connection (in a separate thread)
hiloEscuchas = new ConnectedThread(mmSocket);
hiloEscuchas.run();
}
/** Will cancel an in-progress connection, and close the socket */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
private boolean conectado;
public ConnectedThread(BluetoothSocket socket) {
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
conectado = false;
mHandler = new Handler();
// Get the input and output streams, using temp objects because
// member streams are final
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) { }
mmInStream = tmpIn;
mmOutStream = tmpOut;
conectado = true;
}
public boolean isConnected(){
return conectado;
}
public void run() {
byte[] buffer = new byte[1024]; // buffer store for the stream
int bytes; // bytes returned from read()
// Keep listening to the InputStream until an exception occurs
while (true) {
try {
cmd = "A";
bytes_enviar = cmd.getBytes();
hiloEscuchas.write(bytes_enviar);
// Read from the InputStream
bytes = mmInStream.read(buffer);
// Send the obtained bytes to the UI Activity
mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer)
.sendToTarget();
} catch (IOException e) {
break;
}
}
}
/* Call this from the main Activity to send data to the remote device */
public void write(byte[] bytes) {
try {
mmOutStream.write(bytes);
} catch (IOException e) { }
}
/* Call this from the main Activity to shutdown the connection */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
}
There was some code to make a bluetooth scan for devices, but in order to get things simple until it works, I wrote the MAC address manually into a variable. Comments explain this, and also shows where it gets stuck.
Thanks

Can anybody please help me with this? I'm stuck and I need Bluetooth connection working for my thesys

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I have currently created a simple tcp socket client application that sends and receives messages from a dotnet server application I have created. The application itself actually works however there are a few things I would like to know if they are possible or not. Also this is my first ever droid application and my first ever java application so I am sure there is a better way to do what I have written so please go easy on me.
The problem that I am having is I need a way to monitor the status of the socket so that if the connection gets dropped whether it is from the server application ending or a network drop that the android client would disconnect and put a notification on the screen letting me know. Currently if I end the server application nothign happens on the client and it acts like the connection is still open. Granted this is probably due to the way I have it written so I am looking for samples or suggestions on how to change this so I can monitor this. Any help would be great. Eventually this will be put into a much larger project for my home but I am starting off small so I can do it correctly the first time rather than having someing messy later on.
My code is listed below.
Thanks
KJ
Source:
package com.kkearney.tcp1;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class TCPClient1Activity extends Activity {
public static final int BUFFER_SIZE = 2048;
private Socket sck = null;
private PrintWriter out = null;
private BufferedReader in = null;
Button btnSend;
Button btnConnect;
Button btnDisconnect;
EditText textOut;
TextView textIn;
String response = "";
final Handler handler = new Handler();
final Runnable updateUI = new Runnable() {
public void run() {
textIn.setText(response);
}
};
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
textOut = (EditText)findViewById(R.id.txtSend);
textIn = (TextView)findViewById(R.id.txtMSG);
btnSend = (Button)findViewById(R.id.btnSend);
btnConnect = (Button)findViewById(R.id.btnConnect);
btnDisconnect = (Button)findViewById(R.id.btnDisconnect);
}
public void ConnectUp(View view){
OpenConnection();
}
public void OpenConnection(){
new Thread(new Runnable(){
public void run(){
try{
if (sck == null){
sck = new Socket("10.0.0.135",8080);
sck.setKeepAlive(true);
screenConfig();
in = new BufferedReader(new InputStreamReader(sck.getInputStream()));
out = new PrintWriter(sck.getOutputStream());
sendDataWithString("testing 1 2 3");
int charsRead = 0;
char[] buffer = new char[BUFFER_SIZE];
while ((charsRead = in.read(buffer)) != -1) {
response += new String(buffer).substring(0, charsRead);
handler.post( updateUI );
}
screenConfig();
}
}
catch (IOException e) {
System.out.print(e+"");
}
catch (Exception e) {
System.out.print(e+"");
}
}
}).start();
}
public void screenConfig(){
if (sck.isClosed() == false){
textOut.setClickable(true);
btnSend.setClickable(true);
btnDisconnect.setClickable(true);
btnConnect.setClickable(false);
}else{
textOut.setClickable(false);
btnSend.setClickable(false);
btnDisconnect.setClickable(false);
btnConnect.setClickable(true);
}
}
public void SendMessage(View view){
sendDataWithString(textOut.getText().toString());
textOut.setText(null);
}
public void DisConnect(View view){
CloseConnection();
}
public void CloseConnection(){
if (sck != null) {
try {
sck.close();
screenConfig();
} catch (IOException e) {
e.printStackTrace();
} finally {
sck = null;
}
}
}
public void sendDataWithString(String message) {
if (message != null && sck != null) {
out.write(message);
out.flush();
}
}
}

android quiz help

So I've decided to to teach myself how to program for android and have a general understanding for java. Well i decided to borrow someones code from the internet and utilize it to assist in creating my first quiz app. I am getting some errors in this code and was wondering if anyone would be so kind to assist me. Thanks
Code:
package com.danyluk.MedicStudyGuide;
import java.io.IOException;
import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
public class Quiz extends Activity{
/** Called when the activity is first created. */
private RadioButton radioButton;
private TextView quizQuestion;
private TextView tvScore;
private int rowIndex = 1;
private static int score=0;
private int questNo=0;
private boolean checked=false;
private boolean flag=true;
private RadioGroup radioGroup;
String[] corrAns = new String[5];
final DataBaseHelper db = new DataBaseHelper(this);
Cursor c1;
Cursor c2;
Cursor c3;
int counter=1;
String label;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.quiz);
String options[] = new String[19];
// get reference to radio group in layout
RadioGroup radiogroup = (RadioGroup) findViewById(R.id.rdbGp1);
// layout params to use when adding each radio button
LinearLayout.LayoutParams layoutParams = new RadioGroup.LayoutParams(
RadioGroup.LayoutParams.WRAP_CONTENT,
RadioGroup.LayoutParams.WRAP_CONTENT);
try {
db.createDataBase();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
c3 = db.getCorrAns();
tvScore = (TextView) findViewById(R.id.tvScore);
for (int i=0;i<=4;i++)
{
corrAns[i]=c3.getString(0);
c3.moveToNext();
}
RadioGroup radioGroup = (RadioGroup) findViewById(R.id.rdbGp1);
radioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener() {
public void onCheckedChanged(RadioGroup group, int checkedId) {
// TODO Auto-generated method stub
for(int i=0;;){
RadioButton btn = (RadioButton) radioGroup.getChildAt(i);
String text;
if (btn.isPressed() && btn.isChecked() && questNo < 5)
{
Log.e("corrAns[questNo]",corrAns[questNo]);
if (corrAns[questNo].equals(btn.getText()) && flag==true)
{
score++;
flag=false;
checked = true;
}
else if(checked==true)
{
score--;
flag=true;
checked = false;
}
}
}
tvScore.setText = ("Score: " + Integer.toString(score) + "/5");
Log.e("Score:", Integer.toString(score));
}
});
quizQuestion = (TextView) findViewById(R.id.TextView01);
displayQuestion();
/*Displays the next options and sets listener on next button*/
Button btnNext = (Button) findViewById(R.id.btnNext);
btnNext.setOnClickListener(btnNext_Listener);
/*Saves the selected values in the database on the save button*/
Button btnSave = (Button) findViewById(R.id.btnSave);
btnSave.setOnClickListener(btnSave_Listener);
}
/*Called when next button is clicked*/
private View.OnClickListener btnNext_Listener= new View.OnClickListener() {
@Override
public void onClick(View v) {
flag=true;
checked = false;
questNo++;
if (questNo < 5)
{
c1.moveToNext();
displayQuestion();
}
}
};
/*Called when save button is clicked*/
private View.OnClickListener btnSave_Listener= new View.OnClickListener() {
@Override
public void onClick(View v) {
}
};
private void displayQuestion()
{
//Fetching data quiz data and incrementing on each click
c1=db.getQuiz_Content(rowIndex);
c2 =db.getAns(rowIndex++);
quizQuestion.setText(c1.getString(0));
radioGroup.removeAllViews();
for (int i=0;i<=3;i++)
{
//Generating and adding 4 radio buttons dynamically
radioButton = new RadioButton(this);
radioButton.setText(c2.getString(0));
radioButton.setId(i);
c2.moveToNext();
radioGroup.addView(radioButton);
}
}}}
You forgot give us the error that you get

Q> HELP Connection andrdoid to pc Programming

this is my server code
i am getting an error on my android phone when i clicked the device address
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import javax.bluetooth.*;
import javax.microedition.io.*;
public class ServerSide {
//private static LocalDevice localDevice;
static LocalDevice localDevice;
DiscoveryAgent agent;
private void startServer() throws IOException{
UUID uuid = new UUID("112f8dbf1e46442292b6796539467bc9", false);
String connectionString = "btspp://localhost:" + uuid
+";name=SampleSPPServer";
//open server url
StreamConnectionNotifier streamConnNotifier =
(StreamConnectionNotifier)Connector.open( connectionString );
System.out.println("\nServer Started. Waiting for clients to
connect...");
StreamConnection connection=streamConnNotifier.acceptAndOpen();
RemoteDevice dev = RemoteDevice.getRemoteDevice(connection);
System.out.println("Remote device address:
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System.out.println("Remote device name:
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}
public static void main(String[] args) {
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System.out.println("Address: "+localDevice.getBluetoothAddress());
System.out.println("Name: "+localDevice.getFriendlyName());
}catch(Exception e){
System.err.println(e.toString());
System.err.println(e.getStackTrace());
e.printStackTrace();}
try{
ServerSide sampleSPPServer=new ServerSide();
sampleSPPServer.startServer();
}catch(Exception e){
System.err.println(e.toString());
System.err.println(e.getStackTrace());
e.printStackTrace();}
}
}
**************************************************************
and this is my client(android) code
package client.side;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.UUID;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class ClientSideActivity extends Activity {
int REQUEST_ENABLE_BT = 0;
private BluetoothAdapter mBluetoothAdapter;
private ArrayAdapter<String> mArrayAdapter;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button btn1 = (Button)findViewById(R.id.button1);
Button btn2 = (Button)findViewById(R.id.button2);
final ListView lv1 = (ListView)findViewById(R.id.listView1);
final TextView out = (TextView)findViewById(R.id.textView1);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
mArrayAdapter = new
ArrayAdapter<String>(this,android.R.layout.simple_list_item_1);
if (!mBluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new
Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent,
REQUEST_ENABLE_BT);
}
out.setText(null);
btn1.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
out.setText("Paired Devices");
Set<BluetoothDevice> pairedDevices =
mBluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0){
for(BluetoothDevice device : pairedDevices){
mArrayAdapter.add(device.getName() + "\n" +
device.getAddress());
}
}
lv1.setAdapter(mArrayAdapter);
}
});
btn2.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
out.setText("Discovered Devices");
mBluetoothAdapter.startDiscovery();
Toast msg = Toast.makeText(ClientSideActivity.this, "Discovering
Devices please wait.", Toast.LENGTH_LONG);
msg.show();
final BroadcastReceiver mReceiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
// When discovery finds a device
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
// Get the BluetoothDevice object from the Intent
BluetoothDevice device =
intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
// Add the name and address to an array adapter to show
in a ListView
mArrayAdapter.add(device.getAddress());
} }
};
// Register the BroadcastReceiver
IntentFilter filter = new
IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mReceiver, filter); // Don't forget to unregister
during onDestroy
}
});
lv1.setOnItemClickListener(new OnItemClickListener()
{
public void onItemClick(AdapterView<?> arg0, View arg1, int
position,long id)
{
out.setText(arg0.getItemAtPosition(position).toString());
BluetoothDevice remoteDev = (BluetoothDevice)
arg0.getItemAtPosition(position);
ConnectThread conDev = new ConnectThread(remoteDev);
conDev.start();
}
});
}
public class ConnectThread extends Thread {
private final UUID MY_UUID =
UUID.fromString("112f8dbf1e46442292b6796539467bc9");
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
public ConnectThread(BluetoothDevice device) {
// Use a temporary object that is later assigned to
mmSocket,
// because mmSocket is final
BluetoothSocket tmp = null;
mmDevice = device;
try {
// MY_UUID is the app's UUID string, also used by the
server code
tmp =
device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) { }
mmSocket = tmp;
}
public void run() {
// Cancel discovery because it will slow down the
connection
mBluetoothAdapter.cancelDiscovery();
try {
// Connect the device through the socket. This will
block
// until it succeeds or throws an exception
mmSocket.connect();
} catch (IOException connectException) {
// Unable to connect; close the socket and get out
try {
mmSocket.close();
} catch (IOException closeException) { }
return;
}
// Do work to manage the connection (in a separate
thread)
}
/** Will cancel an in-progress connection, and close the
socket */
}
}

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I am trying to make an app that on launch reads the current on/off(1,0) value of /sys/class/mdnie/mdnie/negative, then changes it to "0 or 1. Someone suggested the below, and I tried it and it does nothing any help is apreciated. Obvously I am a beginner and barely know how to write code but hey gotta start somewhere, this is for a visually impaired friend to toggle negative color mode by assigning a shortcut key to the app. I think it has to do with needing root permision to edit those settings.
Code:
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import android.app.Activity;
import android.os.Bundle;
public class ToggleNegativeColorsActivity extends Activity {
private static final String FILEPATH = "/sys/class/mdnie/mdnie/negative";
@Override
public void onCreate(Bundle savedInstanceState) {
try {
String value = readFileAsString(FILEPATH);
if ("1".equals(value.trim())) {
writeStringToFile(FILEPATH, "0");
}
else {
writeStringToFile(FILEPATH, "1");
}}
catch (IOException e) {
e.printStackTrace();
}
finish();
}
// Grabbed from http://stackoverflow.com/questions/1656797/how-to-read-a-file-into-string-in-java
private String readFileAsString(String filePath) throws IOException {
StringBuffer fileData = new StringBuffer();
BufferedReader reader = new BufferedReader(
new FileReader(filePath));
char[] buf = new char[1024];
int numRead;
while((numRead=reader.read(buf)) != -1){
String readData = String.valueOf(buf, 0, numRead);
fileData.append(readData);
}
reader.close();
return fileData.toString();
}
// Grabbed from http://stackoverflow.com/questions/1053467/how-do-i-save-a-string-to-a-text-file-using-java
private void writeStringToFile(String filePath, String value) throws IOException {
PrintWriter out = new PrintWriter(filePath);
out.print(value);
out.close();
}
}

Bluetooth scanning and connecting android studio

Hi,
I'm new in this forum so I don't know if i'm in the correct section...
I created this class named BLEConnection becuase i'm tring to connect to a esp32 via BLE but i'm having some problem in the connection part... the class:
Java:
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattService;
import android.bluetooth.BluetoothManager;
import android.bluetooth.BluetoothProfile;
import android.bluetooth.le.BluetoothLeScanner;
import android.bluetooth.le.ScanCallback;
import android.bluetooth.le.ScanFilter;
import android.bluetooth.le.ScanResult;
import android.bluetooth.le.ScanSettings;
import android.content.Context;
import android.os.ParcelUuid;
import android.util.Log;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
public class BLEConnection {
private BluetoothAdapter mBluetoothAdapter;
private BluetoothLeScanner mBluetoothLeScanner;
private String mTargetDeviceAddress;
private boolean mScanning;
private BLEConnectionListener mListener;
private BluetoothGatt mBluetoothGatt;
private Context mContext;
private BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
// This callback is invoked when the connection state changes, e.g. from disconnected to connected.
if (newState == BluetoothProfile.STATE_CONNECTED) {
Log.e("bleee", "connected ");
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
Log.e("bleee", "disconected");
}
}
};
private ScanCallback mScanCallback = new ScanCallback() {
@Override
public void onScanResult(int callbackType, ScanResult result) { // This callback is invoked when a BLE advertisement is found.
Log.e("bleee", "scan result");
BluetoothDevice device = result.getDevice();
if (device.getAddress().equals(mTargetDeviceAddress)) {
Log.e("bleee", "device found 1");
mBluetoothLeScanner.stopScan(mScanCallback);
mScanning = false;
mListener.onDeviceFound(device);
}
}
@Override
public void onBatchScanResults(List<ScanResult> results) { // This callback is invoked when multiple BLE advertisements are found at once.
Log.e("bleee", "scan result multiple");
for (ScanResult result : results) {
BluetoothDevice device = result.getDevice();
if (device.getAddress().equals(mTargetDeviceAddress)) {
Log.e("bleee", "batch scan multiple");
mBluetoothLeScanner.stopScan(mScanCallback);
mScanning = false;
mListener.onDeviceFound(device);
break;
}
}
}
@Override
public void onScanFailed(int errorCode) {
Log.e("bleee", "scan failed 1");
mScanning = false;
mListener.onScanFailed(errorCode);
}
};
public BLEConnection(Context context, String targetDeviceAddress, BLEConnectionListener listener) {
mTargetDeviceAddress = targetDeviceAddress;
mListener = listener;
BluetoothManager bluetoothManager = (BluetoothManager) context.getSystemService(Context.BLUETOOTH_SERVICE);
mBluetoothAdapter = bluetoothManager.getAdapter();
mBluetoothLeScanner = mBluetoothAdapter.getBluetoothLeScanner();
}
public void startScan() {
Log.e("bleee", "starting scan..................");
if (mScanning) {
return;
}
List<ScanFilter> filters = new ArrayList<>();
ScanFilter filter = new ScanFilter.Builder()
.setDeviceAddress(mTargetDeviceAddress)
.build();
filters.add(filter);
ScanSettings settings = new ScanSettings.Builder()
.setScanMode(ScanSettings.SCAN_MODE_LOW_POWER)
.setCallbackType(ScanSettings.CALLBACK_TYPE_ALL_MATCHES)
.setMatchMode(ScanSettings.MATCH_MODE_AGGRESSIVE)
.setNumOfMatches(ScanSettings.MATCH_NUM_ONE_ADVERTISEMENT)
.setReportDelay(0L)
.build();
mBluetoothLeScanner.startScan(filters, settings, mScanCallback);
mScanning = true;
Log.e("bleee", "finished?");
}
public void stopScan() {
Log.e("bleee", "something stopped the scan");
if (mScanning) {
mBluetoothLeScanner.stopScan(mScanCallback);
mScanning = false;
}
}
public void writeMessage(byte[] message) {
Log.e("bleee", "writing message...............");
if (mBluetoothGatt == null) {
return;
}
BluetoothGattService service = mBluetoothGatt.getService(UUID.fromString("4fafc201-1fb5-459e-8fcc-c5c9c331914b"));
if (service == null) {
return;
}
BluetoothGattCharacteristic characteristic = service.getCharacteristic(UUID.fromString("beb5483e-36e1-4688-b7f5-ea07361b26a8"));
if (characteristic == null) {
return;
}
characteristic.setValue(message);
mBluetoothGatt.writeCharacteristic(characteristic);
}
public interface BLEConnectionListener {
void onDeviceFound(BluetoothDevice device);
void onScanFailed(int errorCode);
}
public void connectToDevice(BluetoothDevice device) {
Log.e("bleee", "Trying connecting");
mBluetoothGatt = device.connectGatt(mContext, false, mGattCallback);
}
public void disconnectFromDevice() {
if (mBluetoothGatt != null) {
mBluetoothGatt.disconnect();
mBluetoothGatt.close();
mBluetoothGatt = null;
}
}
}
please ignore that android studio thinks that some code is an error (because could not be safe and could crash if Bluetooth is not enable, but i'll skip for now this).
So now, I have a service that is this (eliminated useless method for my problem):
Java:
import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.Service;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.IBinder;
import android.util.Log;
//import com.welie.blessed.*;
public class SendNotifyService extends Service implements BLEConnection.BLEConnectionListener {
private volatile boolean shouldStopThread;
private volatile boolean oksend = false;
private String ESP32_MAC_ADDRESS = "84:F7:03:68:06:52";
private BLEConnection mBLEConnection;
public SendNotifyService() {}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
shouldStopThread = false;
mBLEConnection = new BLEConnection(this, ESP32_MAC_ADDRESS, this);
// Start scanning for the device
mBLEConnection.startScan();
new Thread(new Runnable() {
@Override
public void run() {
while (!shouldStopThread) {
//-----------------------------------------------------------------------------------------------------
if(oksend == true){
byte[] message = "Hello, device!".getBytes();
mBLEConnection.writeMessage(message);
}
Log.e("Service Ard_OS", "Service is running...");
Log.e("Service Ard_OS", mac);
pause(4000);
//-----------------------------------------------------------------------------------------------------
}}
public void pause(int millis){ try { Thread.sleep(millis); } catch (InterruptedException e) { e.printStackTrace(); } }
}).start();
return START_STICKY;
}
@Override
public void onDeviceFound(BluetoothDevice device) {
Log.e("bleee", "device found 2");
oksend = true;
mBLEConnection.connectToDevice(device);
}
@Override
public void onScanFailed(int errorCode) {
Log.e("bleee", "scan failed, i think...");
}
}
Now it comes the problem:
Obviously I'm using a real phone (samsung galaxy a20e) that runs API 30.
When I start the Service in the LOGCAT using the filter "bleee" i can only see theese two debug message:
------------------ PROCESS STARTED (9353) for package com.example.ard_os ------------------
2023-01-03 22:52:02.993 9353-9353 bleee com.example.ard_os E starting scan..................
2023-01-03 22:52:03.012 9353-9353 bleee com.example.ard_os E finished?
Click to expand...
Click to collapse
So the problem is that i don't get nothing else, not in the BluetoothGattCallback and not even in the ScanCallback. It doesn't connect to the device... If I was not clear about something I will answer!
Thanks to everyone.
I fixed, while this functions were called in a Service I needed the ACCESS_BACKGROUND_LOCATION to scan... So my manifest is now:
<uses-permission-sdk-23 android:name="android.permission.ACCESS_FINE_LOCATION" tools:node="remove" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission-sdk-23 android:name="android.permission.ACCESS_COARSE_LOCATION" tools:node="remove" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_BACKGROUND_LOCATION" android:maxSdkVersion="30" />
<uses-feature android:name="android.hardware.bluetooth_le" android:required="true"/>
<uses-feature android:name="android.hardware.bluetooth" android:required="true"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
rember that some of these permissions needs the user approvment, so you need the Run Time Permission.
table with needed permissions to scan:
18 to 22 (No runtime permissions needed)
23 to 28 One of below:
- android.permission.ACCESS_COARSE_LOCATION
- android.permission.ACCESS_FINE_LOCATION
29 to 30 - android.permission.ACCESS_FINE_LOCATION
- android.permission.ACCESS_BACKGROUND_LOCATION*
31 to current - android.permission.BLUETOOTH_SCAN
- android.permission.ACCESS_FINE_LOCATION**
* Needed if scan is performed in background
** Only needed if you want to obtain user's location with BLE scanning (BLUETOOTH_SCAN is not using neverForLocation attribute in your App)

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