I am trying to pass data from a Qdialog (Login dialog) to my mainWindow after a successful login and was wondering if it is possible to use Signals and slots to achieve this. Here is my Main.cpp file so far in which I connect my Login Dialog to main window:
int main(int argc, char *argv[]){
QApplication a(argc, argv);
Login l;
l.createConnection();
MainWindow w;
l.show();
QObject::connect(&l, SIGNAL(accept()), &w, SLOT(show()));
QObject::connect(&w, SIGNAL(Logout()), &l, SLOT(show()));
return a.exec();
}
The signal accept emits from the Dialog after the user inserts correct username/password and I would like afterwards to pass the information relative to this user to my main window.
The user class I'm trying to pass:
class User
{
QString ID;
QString username;
QString password;
QString name;
QString Status;
public:
User();
User(QString, QString, QString, QString, QString);
~User();
};
What is the best approach for this?
For a new type to be used in the signals you must register it using the macro: Q_DECLARE_METATYPE
user.h
#ifndef USER_H
#define USER_H
#include <QString>
#include <QMetaType>
class User
{
[...]
};
Q_DECLARE_METATYPE(User)
#endif // USER_H
Then it is used as parameter of the accept signal in your case:
login.h
signals:
void accept(const User & user);
Then you issue it when necessary:
User user("1", "2", "3", "4", "5");
emit accept(user);
To make it simple you can connect using a lambda function, but for this we create a method that you get to use in MainWindow:
mainwindow.h
public:
void setUser(const User &user);
private:
User mUser;
mainwindow.cpp
void MainWindow::setUser(const User& user)
{
mUser = user;
qDebug()<<mUser.toString();
}
main.cpp
int main(int argc, char *argv[]){
QApplication a(argc, argv);
Login l;
l.createConnection();
MainWindow w;
l.show();
QObject::connect(&l, &Login::accept, [&w](const User user){
w.setUser(user);
w.show();
});
QObject::connect(&w, &MainWindow::Logout, &l, &Login::show);
return a.exec();
}
You can find a complete example in the following link.
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