QML check from C ++ signal

[Nio74]

I have to check that the user has entered the pc's ip where the socket connects, I have a backend in C ++ where on the constructor I wanted to do this check which then sent a signal to the qml, but I believe that the qml can't do it not being instantiated the Backend class, how could I do?


C++ Backend constructor


Backend::Backend(QObject *parent) : QObject(parent)


{
settings = new QSettings("$HOME/.config/MySoft.ini",QSettings::IniFormat);

settings->setValue("ipcasa","192.168.1.8");
if (settings->contains("ipcasa"))
{
ip = settings->value("ipcasa").toString();

}else {

qDebug() << "insert your Ip";
emit statusChanged(" You must insert to Ip");


client = new ClientResearch(ip,6547);

connect(client, &ClientResearch::hasReadSome, this, &Backend::receivedSomething);
connect(client, &ClientResearch::statusChanged, this, &Backend::setStatus);
// FIXME change this connection to the new syntax
connect(client->tcpSocket, SIGNAL(error(QAbstractSocket::SocketError)),
this, SLOT(gotError(QAbstractSocket::SocketError)));

//connect data to source database
connect(client, &ClientResearch::sendRiparazione, this ,&Backend::recivedRiparazione);





}

QML


ApplicationWindow {
id: window
width: 500
height: 500

visible:true



Backend{
id: backend

onStatusChanged: {


messageDialog.text = newStatus
messageDialog.setVisible(true);
}


}

MessageDialog{

id: messageDialog
title: "Attention"
onAccepted: {
console.log("message for insert ip start.")
// Qt.quit()

}
// Component.onCompleted: visible = true
}

[anda_skoa]

A constructor can't really send a signal.

Connections to signals can only be done on fully formed objects, which means the constructor must have completed.

Independent of that: a status is usually something that is always present and only changes from time to time. So the way to expose that to QML is to use a Q_PROPERTY

Cheers,
_