Serializing a widget

[JKSH]

@EL-jos said in Serializing a widget:

I want to make sure that if we send a message to a client that is not connected, that this client sees the message that has been sent as soon as it is connected.

Then the central server must store the message. When the client comes online, the server can deliver the message to the client.

Note: This concept is about communications architecture. This is not related to widgets at all.

[EL-jos]

ahhhhh yes you're right, so I can store the message in a database at the server level then as soon as the concerned client is connected the server will be able to restore the message then send it to the client, thank you very much.

then a second unresolved problem so far;
here I have a scrollArea which first contains many widgets of different type, so I want to delete either empty all these widgets and left the scrollArea blank so without element,
how do I do that?

[JKSH]

@EL-jos said in Serializing a widget:

here I have a scrollArea which first contains many widgets of different type, so I want to delete either empty all these widgets and left the scrollArea blank so without element,
how do I do that?

Have a read through http://doc.qt.io/qt-5/qscrollarea.html . Do you see anything that might do what you want?

[EL-jos]

I just read and reread the Qt documentation for the QScrollArea class or even its mother classes but I can't find the solution to my problem because there is not a function that allows to remove all widgets contained in a scrollAreea

[mrjj]

@EL-jos
Hi
Are the widgets not in a layout ?
You can clear layout with

void clearLayout(QLayout *layout)
    QLayoutItem *item;
    while((item = layout->takeAt(0))) {
        if (item->layout()) {
            clearLayout(item->layout());
            delete item->layout();
        }
        if (item->widget()) {
            delete item->widget();
        }
        delete item;
    }
}

[EL-jos]

Thank you for your code.
theoretically it works but not in practice according to my example, here is a little project I created to test your code:

[7_1535474695539_fenetre1.cpp](Uploading 100%) [6_1535474695538_fenetre1.h](Uploading 100%) [5_1535474695538_fenetresecond.cpp](Uploading 100%) [4_1535474695537_fenetresecond.h](Uploading 100%) [3_1535474695537_fenetresecond.ui](Uploading 100%) [2_1535474695537_main.cpp](Uploading 100%) [1_1535474695535_Oc.pro](Uploading 100%) [0_1535474695483_Oc.pro.user](Uploading 100%)

[EL-jos]

sorry I can't send my project on topic, send me your E-mail address so I can send it to you by E-mail

[mrjj]

@EL-jos
Sorry i dont have email i use for Qt forum.
You can use dropbox or google drive.
Are you sure u give it the correct layout ?
Im sure code works so maybe its other layout u clear that u think.
also use the debugger to see what happens.

[EL-jos]

Yes thank you sorry it was a small mistake on my part and there it works correctly, here is the code:

void Controleur::on_pushButton_clicked()
{
    QLayoutItem *item;

    int nb = 3;
    int a = 0;
    qDebug() << nb;

    while(ui->scrollAreaWidgetContents->layout()->count() > 0){

    for(int i = 0; i < ui->scrollAreaWidgetContents->layout()->count(); ++i){

        item = ui->scrollAreaWidgetContents->layout()->takeAt(i);
        if(item->layout()){

            qDebug("It's a layout");
            delete item->layout();
        }

        if(item->widget()){

            qDebug("It's a widget");
            delete item->widget();
        }

        delete item;
    }

    qDebug() << "suppression N°" << a;
    ++a;
    }
}

[mrjj]

@EL-jos
Hi
Ok super.
You also want to remove any layout it has ?
Normally one wish to keep layout and only remove widgets.

[EL-jos]

Hi,
I'm sorry I'm not here;
Yes, I just wanted to remove the widgets, not the layout.

I take this opportunity to ask a question I don't understand.
here is the server and client code:

• Server

     QTcpServer *serveur = new QTcpServer(this);
    iserveur->listen(QHostAddress::Any, 50885);

• client

QTcpSocket *socket  = new QTcpSocket(this); 
socket->abort();
    socket->connectToHost("127.0.0.1", 50885);

so we understand that my server accepts any type of address, such as: Local IP, Internal IP and Internet IP.
but strangely as soon as I execute my code, the server accepts that the local IP: 127.0.0.1 and the internal IP: 192.168.X.X, as far as the internet IP is concerned this does not pass and there is a message telling me time is out.

do you know how I can connect to the server via Internet IP?

[SGaist]

Check your network and firewall settings.

[EL-jos]

so since I'm on windows 10 how should my firewall be?

[SGaist]

Please do your homework.

[JKSH]

@EL-jos said in Serializing a widget:

the server accepts that the local IP: 127.0.0.1 and the internal IP: 192.168.X.X, as far as the internet IP is concerned this does not pass and there is a message telling me time is out.

That's because:

• When your client tries to connect to a local/internal IP address, the connection stays within the same PC.
• When your client tries to connect to an "Internet IP" address, the connection reaches your server's Router. You must tell your Router to forward the connection to your Server PC.

If you want to create an application that communicates over the Internet, you must first understand the topic of Port Forwarding (e.g. https://en.wikipedia.org/wiki/Port_forwarding ). And like @SGaist said, you must configure your Server's firewall to accept the connection.

Note: Port Forwarding and Firewall configuration are topics outside the scope of Qt. Please do your homework and research these topics online.

[EL-jos]

Yes you are right but except I just allowed my application to communicate through the windows firewall (public and private) but the client still can't connect to the server via ip/internet.

Please help me.

here is my example code:

Controleur::Controleur(QWidget *parent) :
    QDialog(parent)
{
    setupUi(this);

    serveur = new QTcpServer(this);
    QObject::connect(serveur,SIGNAL(newConnection()),this,SLOT(on_newConnection()));

    client = new QTcpSocket(this);
    QObject::connect(client,SIGNAL(connected()),this,SLOT(on_connected()));
    QObject::connect(client,SIGNAL(stateChanged(QAbstractSocket::SocketState socketState)),this,SLOT(on_stateChanged(QAbstractSocket::SocketState socketState)));
    QObject::connect(client,SIGNAL(error(QAbstractSocket::SocketError socketError)),this,SLOT(on_error(QAbstractSocket::SocketError socketError)));
}


void Controleur::on_newConnection(){

    qDebug("New connection");
}

void Controleur::on_pushButton_clicked()
{
    // dem. serveur

    serveur->listen(QHostAddress::AnyIPv4,40885);

    if(serveur->isListening())
        qDebug("The server is ready for listening");
    if(!serveur->isListening())
        qDebug("The server is not listening");

}

void Controleur::on_pushButton_2_clicked()
{
    // con. client

    client->abort();
    client->connectToHost("196.92.6.87",50885);
    qDebug("Attempt to connect to the server...");

}

[JKSH]

@EL-jos said in Serializing a widget:

I just allowed my application to communicate through the windows firewall (public and private) but the client still can't connect to the server via ip/internet.

Read my previous post again about Routers and Port Forwarding. The problem is not in your code.