Using subscribe_position to Display Drone Continuous Position in QT


am trying to receive drone position and display it on a QT GUI qlineedit.
I have the code for position, but the problem when I test it using px4 I received the position once, and I need a continuous movement. The code is same as the takeoff and landing example.

Mavsdk mavsdk;
ConnectionResult connection_result = mavsdk.add_any_connection("udp://:14540");

if (connection_result != ConnectionResult::Success) {
    std::cerr << "Connection failed: " << connection_result << '\n';
    return 1;
auto system = get_system(mavsdk);
if (!system) {
    return 1;

// Instantiate pluginis.
auto telemetry = Telemetry{system};
auto action = Action{system};

// We want to listen to the altitude of the drone at 1 Hz.
const auto set_rate_result = telemetry.set_rate_position(1);
if (set_rate_result != Telemetry::Result::Success) {
    std::cerr << "Setting rate failed: " << set_rate_result << '\n';
    return 1;

telemetry.subscribe_position([&](Telemetry::Position position) {
    emit updateAvAlt(position.relative_altitude_m);
    emit updateAvLatLong(position.latitude_deg, position.longitude_deg);

and the emit call the display function.

void Status::setAvLatLong(double avLatitude, double avLonitude)
    ui->avPos->setPosition(avLatitude, avLonitude);

void Status::setAvValueGreen()

could you please help?