How can i check if QMainWindow is fully loaded ?

[ChrisW67]

What do you mean by "fully loaded"?

You can trigger some activity when the program returns to the Qt event loop with a single-shot timer at the end of the constructor:

#include <QtGui>
#include <QDebug>
 
class MainWindow: public QMainWindow {
    Q_OBJECT
    QLabel *label1;
    QLabel *label2;
public:
    MainWindow(QWidget *p = 0): QMainWindow(p) {
        QWidget *central = new QWidget(this);
        label1 = new QLabel("Label 1", this);
        label2 = new QLabel("Label 2", this);
 
        QVBoxLayout *layout = new QVBoxLayout(central);
        layout->addWidget(label1);
        layout->addWidget(label2);
 
        central->setLayout(layout);
        setCentralWidget(central);
 
        QTimer::singleShot(0, this, SLOT(doLater()));
    }
public slots:
    void doLater() {
        // Executes when event loop reached (after show in this case)
        label2->setText("I've been changed");
    }
 
private:
};
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
 
    MainWindow m;
    m.show();
    return app.exec();
}
#include "main.moc"

#include <QtGui>
#include <QDebug>

class MainWindow: public QMainWindow {
    Q_OBJECT
    QLabel *label1;
    QLabel *label2;
public:
    MainWindow(QWidget *p = 0): QMainWindow(p) {
        QWidget *central = new QWidget(this);
        label1 = new QLabel("Label 1", this);
        label2 = new QLabel("Label 2", this);

        QVBoxLayout *layout = new QVBoxLayout(central);
        layout->addWidget(label1);
        layout->addWidget(label2);

        central->setLayout(layout);
        setCentralWidget(central);

        QTimer::singleShot(0, this, SLOT(doLater()));
    }
public slots:
    void doLater() {
        // Executes when event loop reached (after show in this case)
        label2->setText("I've been changed");
    }

private:
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    MainWindow m;
    m.show();
    return app.exec();
}
#include "main.moc"

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[nish]

also try showEvent()