How to scanning for bluetooth devices?

victor wang

Hi All,
I'm using qt5.5 on my computer and using Linux+QT wayland for my OS system.
I wanna scanning for my blutooth devices and I do it with below link.
Document

This is what I write in my program.

void MainWindow::on_play_clicked()
{
QBluetoothLocalDevice localDevice;
QString localDeviceName;

// Check if Bluetooth is available on this device
if (localDevice.isValid()) {

       // Turn Bluetooth on
        localDevice.powerOn();

       // Read local device name
       localDeviceName = localDevice.name();

       // Make it visible to others
       localDevice.setHostMode(QBluetoothLocalDevice::HostDiscoverable);

       // Get connected devices
       QList<QBluetoothAddress> remotes;
       remotes = localDevice.connectedDevices();
 }
else
{
      qDebug("local Device is not available");
}

}

But It always show "local Device is not available".
Why is this happening?
How can I solve this question?
Thanks in Advanced!

SGaist

Hi,

I'd go with the static QBluetoothLocalDevice::allDevices function to check the list of devices and see if anything is available.

Did you also check that you have the bluez libraries installed on your system ?

victor wang

@SGaist
Yes, I had try to connect bluetooth directly from my system last week.
And I'm using bluez5 to do it.
I'm sure it connect perfectly.

But yesterday I found that something going wrong with my system.
I can't "lsusb".
I doubt that it is the problem which caused my device invalid in QT progrm.

I will try again and the advise you gave then that you know the result.
Thanks for the reply.

victor wang

@SGaist
Here I'm using QBluetoothLocalDevice::allDevices() to check the available device.
This is how I designed.

QList<QBluetoothHostInfo> infos = QBluetoothLocalDevice::allDevices();
if(infos.isempty)
{
      qDebug("It is empty");
}

I can't understand why it will show empty.
I'm sure that I can connect my phone by running commands in terminal directly.

Why is infos empty?

SGaist

In that case, you should try to run your application once you connected your phone.

victor wang

@SGaist
Is that you mean I have to connect my phone first then run my QT application?

SGaist

Yes, so you ensure that you have at least one active Bluetooth device on your computer.