My Qt Android Bluetooth code is not working for an Android-13 device when using Qt5.12.3

[ZINE]

Hi,

I have a Qt Android-based code that scan BLE devices and display them on a widget. My code works well when it runs on a Android-8 device (API-level 26) using Qt5.12.3, jdk1.8.0_211, NDK 19.2.5345600 and SDK target=26.
When compiling the code for an Android-13 device (API-level 33), the application is not able to find and display BLE devices. I am also using Qt5.12.3, NDK 19.2.5345600 and SDK target=28 which is the highest SDK supported in my Qt. I also included all required permissions in the manifest.xml file:
android.permission.ACCESS_COARSE_LOCATION
android.permission.ACCESS_FINE_LOCATION
android.permission.BLUETOOTH
android.permission.BLUETOOTH_ADMIN
android.permission.BLUETOOTH_CONNECT
android.permission.BLUETOOTH_SCAN

Here is the output when using the Android-13 device but without correctly finding and displaying BLE devices:

I faced same issue when testing heartrate-game example from Qt: Android-8 device successfully detects nearby BLE devices while Android-13 device could not.

Therefore, is this issue related to the used Qt version and/or the target SDK ? i.e., should I use more recent Qt version (like Qt5.15) and higher target SDK (level 33) ? I prefer to work with Qt5 since it supports .pro files which I am currently using.

Here are the main parts of my code:
#include <QtAndroid>
#include <QAndroidJniObject>

void MainWindow::deviceDiscovered(const QBluetoothDeviceInfo &device)
{
qDebug() << "[BLE] Raw: " << device.name() << device.address().toString();

if(device.coreConfigurations()&QBluetoothDeviceInfo::LowEnergyCoreConfiguration)
{
    qDebug() << "Discovered:" << device.name() << device.address().toString();

if(BLE_liste->findItems(device.name()+"\n"+device.address().toString(),Qt::MatchExactly).count()==0)
    {
BLE_liste->addItem(device.name()+"\n"+device.address().toString());
  *dev_info=device;
QBluetoothDeviceInfo* temp_info=new QBluetoothDeviceInfo;
*temp_info=device;
dev_info_list.append(temp_info);
}
}

}

void MainWindow::searchCharacteristic()
{
if(BLE_service){
foreach (QLowEnergyCharacteristic c, BLE_service->characteristics()) {
if(c.isValid()){
if (c.properties() & QLowEnergyCharacteristic::WriteNoResponse ||
c.properties() & QLowEnergyCharacteristic::Write) {
m_writeCharacteristic = c;
if(c.properties() & QLowEnergyCharacteristic::WriteNoResponse)
m_writeMode = QLowEnergyService::WriteWithoutResponse;
else
m_writeMode = QLowEnergyService::WriteWithResponse;
}
if (c.properties() & QLowEnergyCharacteristic::Read)
m_readCharacteristic = c;

            if(c.properties() & QLowEnergyCharacteristic::Notify)
            {
            m_notificationDesc = c.descriptor(
                        QBluetoothUuid::ClientCharacteristicConfiguration);
            if (m_notificationDesc.isValid())
            {
            BLE_service->writeDescriptor(m_notificationDesc, QByteArray::fromHex("0100"));
            }
            }
        }
    }
}

}

void MainWindow::on_listWidget_itemClicked(QListWidgetItem *item)
{
string = item->text();

string = string.split("\n").at(0); //get the 1st word in string

*dev_info=*(dev_info_list.at(BLE_liste->row(item)));
BLE_controlleur=new QLowEnergyController(*dev_info,this);

connect(BLE_controlleur, SIGNAL(connected()),this,SLOT(device_connected()));
connect(BLE_controlleur, SIGNAL(discoveryFinished()),this,SLOT(service_discovered()));
BLE_controlleur->connectToDevice();

}

void MainWindow::device_connected()
{
BLE_controlleur->discoverServices();
}

void MainWindow::service_discovered()
{
services_discovered=1;
m_servicesUuid = BLE_controlleur->services();

int maxl=m_servicesUuid.length();
for(int i=0;i<maxl;i++)
{

    if(m_servicesUuid.at(i).toString()=="{6e400001-b5a3-f393-e0a9-e50e24dcca9e}")
    {
    BLE_service= BLE_controlleur->createServiceObject(m_servicesUuid.at(i), this);
    connect(BLE_service, SIGNAL(stateChanged(QLowEnergyService::ServiceState)),
    this, SLOT(onServiceStateChanged(QLowEnergyService::ServiceState)));
    connect(BLE_service, SIGNAL(characteristicWritten(QLowEnergyCharacteristic,QByteArray)),
            this, SLOT(update_com_state_(QLowEnergyCharacteristic,QByteArray)));
    connect(BLE_service, SIGNAL(error(QLowEnergyService::ServiceError)),
            this, SLOT(error_slot(QLowEnergyService::ServiceError)));
    connect(Comm_timer, SIGNAL(timeout()),this, SLOT(update_com_state()));
    if(BLE_service->state() == QLowEnergyService::DiscoveryRequired)
    {
      BLE_service->discoverDetails();
     }
     else
    searchCharacteristic();

    BLE_liste->setStyleSheet("QListWidget{background-color: rgba(0,0,0,0);color:rgb(202,233,250);font-weight:bold;font-family:Myriad Pro Regular;font-size:64px;border:4px solid rgb(249,159,65);border-radius:12px;} QListWidget::item:selected{background:rgb(249,159,65);color:rgb(0,0,0);}");

    }

}

}

void MainWindow::onServiceStateChanged(QLowEnergyService::ServiceState s)
{
if (s == QLowEnergyService::ServiceDiscovered)
{
searchCharacteristic();
}
}

void MainWindow::BLE_search_slot()
{
if(agent!=nullptr)
{
delete agent;
}

if(ble_widget->isHidden()==false)
{
if(localDevice.hostMode()==QBluetoothLocalDevice::HostPoweredOff)
{localDevice.powerOn();
    QTimer::singleShot(2000, this, SLOT(BLE_search_slot()));
}
BLE_liste->clear();
dev_info_list.clear();

QtAndroid::requestPermissionsSync({
    "android.permission.ACCESS_FINE_LOCATION",
    "android.permission.BLUETOOTH_SCAN",
    "android.permission.BLUETOOTH_CONNECT"
});

    agent = new QBluetoothDeviceDiscoveryAgent(); // create an object in ctors
    connect(agent, SIGNAL(deviceDiscovered(QBluetoothDeviceInfo)),this, SLOT(deviceDiscovered(QBluetoothDeviceInfo)));
    agent->start(QBluetoothDeviceDiscoveryAgent::LowEnergyMethod);



}

}

[jsulm]

@ZINE Please format your code properly.
For newer Android devices you should also use newer Qt version, 5.12.3 is quite old already and I doubt it officially supports Android 13 (see https://doc.qt.io/archives/qt-5.12/android.html).

[ZINE]

@jsulm Thanks for the feedback. I think that at least Qt5.15 is required to supports Android 13 (see https://medium.com/@shmilysyg/set-android-target-sdk-level-33-in-qt-38bb9049924c). I prefer using Qt5.15.2 since I am using .pro files. Also, I suppose that I need higher JDK and NDK versions.

While I do not think that the issue is related to the code (I tested Qt example and did not work), here is my formatted code:

  void MainWindow::deviceDiscovered(const QBluetoothDeviceInfo &device)
 {
qDebug() << "[BLE] Raw: " << device.name() << device.address().toString();

if(device.coreConfigurations()&QBluetoothDeviceInfo::LowEnergyCoreConfiguration)
{
    qDebug() << "Discovered:" << device.name() << device.address().toString();

if(BLE_liste->findItems(device.name()+"\n"+device.address().toString(),Qt::MatchExactly).count()==0)
    {
BLE_liste->addItem(device.name()+"\n"+device.address().toString());
  *dev_info=device;
QBluetoothDeviceInfo* temp_info=new QBluetoothDeviceInfo;
*temp_info=device;
dev_info_list.append(temp_info);
}
}
}



 void MainWindow::searchCharacteristic()
{
if(BLE_service){
    foreach (QLowEnergyCharacteristic c, BLE_service->characteristics()) {
        if(c.isValid()){
            if (c.properties() & QLowEnergyCharacteristic::WriteNoResponse ||
                c.properties() & QLowEnergyCharacteristic::Write) {
                m_writeCharacteristic = c;
                if(c.properties() & QLowEnergyCharacteristic::WriteNoResponse)
                   m_writeMode = QLowEnergyService::WriteWithoutResponse;
                else
                    m_writeMode = QLowEnergyService::WriteWithResponse;
            }
            if (c.properties() & QLowEnergyCharacteristic::Read)
                m_readCharacteristic = c;

            if(c.properties() & QLowEnergyCharacteristic::Notify)
            {
            m_notificationDesc = c.descriptor(
                        QBluetoothUuid::ClientCharacteristicConfiguration);
            if (m_notificationDesc.isValid())
            {
            BLE_service->writeDescriptor(m_notificationDesc, QByteArray::fromHex("0100"));
            }
            }
            }
            }
           }
           }


    void MainWindow::on_listWidget_itemClicked(QListWidgetItem *item)
    {
   string = item->text();

 string = string.split("\n").at(0); //get the 1st word in string

*dev_info=*(dev_info_list.at(BLE_liste->row(item)));
 BLE_controlleur=new QLowEnergyController(*dev_info,this);
 connect(BLE_controlleur, SIGNAL(connected()),this,SLOT(device_connected()));
connect(BLE_controlleur, SIGNAL(discoveryFinished()),this,SLOT(service_discovered()));
BLE_controlleur->connectToDevice();

}


 void MainWindow::device_connected()
{
 BLE_controlleur->discoverServices();
}

 void MainWindow::service_discovered()
{
services_discovered=1;
m_servicesUuid = BLE_controlleur->services();

int maxl=m_servicesUuid.length();
for(int i=0;i<maxl;i++)
{

    if(m_servicesUuid.at(i).toString()=="{6e400001-b5a3-f393-e0a9-e50e24dcca9e}")
    {
    BLE_service= BLE_controlleur->createServiceObject(m_servicesUuid.at(i), this);
    connect(BLE_service, SIGNAL(stateChanged(QLowEnergyService::ServiceState)),
    this, SLOT(onServiceStateChanged(QLowEnergyService::ServiceState)));
    connect(BLE_service, SIGNAL(characteristicWritten(QLowEnergyCharacteristic,QByteArray)),
            this, SLOT(update_com_state_(QLowEnergyCharacteristic,QByteArray)));
    connect(BLE_service, SIGNAL(error(QLowEnergyService::ServiceError)),
            this, SLOT(error_slot(QLowEnergyService::ServiceError)));
    connect(Comm_timer, SIGNAL(timeout()),this, SLOT(update_com_state()));
    if(BLE_service->state() == QLowEnergyService::DiscoveryRequired)
    {
      BLE_service->discoverDetails();
     }
     else
    searchCharacteristic();

    BLE_liste->setStyleSheet("QListWidget{background-color: rgba(0,0,0,0);color:rgb(202,233,250);font-weight:bold;font-family:Myriad Pro Regular;font-size:64px;border:4px solid rgb(249,159,65);border-radius:12px;} QListWidget::item:selected{background:rgb(249,159,65);color:rgb(0,0,0);}");

    }

}

}

void MainWindow::onServiceStateChanged(QLowEnergyService::ServiceState s)
{
if (s == QLowEnergyService::ServiceDiscovered)
{
    searchCharacteristic();
}
}

void MainWindow::BLE_search_slot()
{
if(agent!=nullptr)
{
delete agent;
}

if(ble_widget->isHidden()==false)
{
if(localDevice.hostMode()==QBluetoothLocalDevice::HostPoweredOff)
{localDevice.powerOn();
    QTimer::singleShot(2000, this, SLOT(BLE_search_slot()));
}
BLE_liste->clear();
dev_info_list.clear();

QtAndroid::requestPermissionsSync({
    "android.permission.ACCESS_FINE_LOCATION",
    "android.permission.BLUETOOTH_SCAN",
    "android.permission.BLUETOOTH_CONNECT"
});

    agent = new QBluetoothDeviceDiscoveryAgent(); // create an object in ctors
    connect(agent, SIGNAL(deviceDiscovered(QBluetoothDeviceInfo)),this, SLOT(deviceDiscovered(QBluetoothDeviceInfo)));
    agent->start(QBluetoothDeviceDiscoveryAgent::LowEnergyMethod);

}
}