Attempting to set QLayout on ..., which already has layout

Hi, im trying to make program including simple version of model from Basic Sort/File Model Example , but I get an empty window and warning :
QWidget::setLayout: Attempting to set QLayout "" on EGlowny "", which already has layout

I've checked code few times and I don't see where I did this.

Here you have fragment of my code:

main.cpp

Code:

---

#include <QApplication>
#include "eglowny.h"
extern QAbstractItemModel *asd(QObject *parent);
extern void wbaze();
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    EGlowny okno;
    okno.setSourceModel(asd(&okno));
    okno.show();
    return app.exec();
}

---

Eglowny.h

Code:

---

#ifndef EGLOWNY_H
#define EGLOWNY_H
#include <QMainWindow>
#include <QMenu>
#include <QMenuBar>
#include <QFileDialog>
#include <QMessageBox>
#include <QAbstractItemModel>
#include <QTreeView>
#include <QSortFilterProxyModel>
#include <QComboBox>
#include <QGridLayout>
extern void wbaze(QString &nazwapliku);
extern void zapiszbaze(QString &nazwapliku);
class ToolBar;
QT_FORWARD_DECLARE_CLASS(QMenu)
QT_FORWARD_DECLARE_CLASS(QSignalMapper)
class EGlowny : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit EGlowny(QWidget *parent = 0);
    void setSourceModel(QAbstractItemModel *model);
private:
   void pasekmenu();
   void wnetrzeokna();
    QSortFilterProxyModel *proxyModel;
    QGridLayout *proxyLayout;
    QTreeView *proxyView;
    QLabel *filterPatternLabel;
    QLabel *filterColumnLabel;
    QLineEdit *filterPatternLineEdit;
    QComboBox *filterColumnComboBox;
private slots:
 
   void filterREChanged();
   void filterColumnChanged();
};
#endif // EGLOWNY_H

---

Eglowny.cpp

Code:

---

#include "eglowny.h"
 
EGlowny::EGlowny(QWidget *parent) :
    QMainWindow(parent)
{
    pasekmenu();
    wnetrzeokna();
    setWindowTitle("Program");
    resize(800, 600);
}
 
void EGlowny::wnetrzeokna()
{
    proxyModel = new QSortFilterProxyModel;
    proxyModel->setDynamicSortFilter(true);
 
    proxyView = new QTreeView;
    proxyView->setRootIsDecorated(false);
    proxyView->setAlternatingRowColors(true);
    proxyView->setModel(proxyModel);
    proxyView->setSortingEnabled(true);
 
    filterPatternLineEdit = new QLineEdit;
    filterPatternLabel = new QLabel(tr("Filter Pattern: "));
 
    filterColumnComboBox = new QComboBox;
    filterColumnComboBox->addItem(tr("1"));
    filterColumnComboBox->addItem(tr("2"));
    filterColumnComboBox->addItem(tr("3"));
    filterColumnLabel = new QLabel(tr("Filter column: "));
 
connect (filterPatternLineEdit, SIGNAL(textChanged(QString)),this,SLOT(filterREChanged()));
    connect (filterColumnComboBox, SIGNAL(currentIndexChanged(int)),this,SLOT(filterColumnChanged()));
 
    proxyLayout = new QGridLayout;
    proxyLayout->addWidget(proxyView, 0, 0, 1, 3);
    proxyLayout->addWidget(filterPatternLabel, 1, 0);
    proxyLayout->addWidget(filterPatternLineEdit, 1, 1, 1, 2);
    proxyLayout->addWidget(filterColumnLabel, 2, 0);
    proxyLayout->addWidget(filterColumnComboBox, 2, 1, 1, 2);
    setLayout(proxyLayout);
 
    proxyView->sortByColumn(1,Qt::AscendingOrder);
    filterColumnComboBox->setCurrentIndex(1);
}
void EGlowny::pasekmenu()
{
    QMenu *Plik = menuBar()->addMenu(tr("Baza"));
    QAction *action = Plik->addAction(tr("..."));
}

---

baz.h - from this file comes extern functions

Code:

---

QAbstractItemModel *asd(QObject *parent)
{
    QStandardItemModel *model = new QStandardItemModel(0, 3, parent);
    model->setHeaderData(0, Qt::Horizontal, QObject::tr("Subject"));
    model->setHeaderData(1, Qt::Horizontal, QObject::tr("Sender"));
    model->setHeaderData(2, Qt::Horizontal, QObject::tr("Date"));
    dodajwpis(model, "as", "qb", "sac","wd");
    dodajwpis(model, "aa", "bs", "sc","asd");
    dodajwpis(model, "xw", "yx", "sz","saa");
    return model;
 }
 
void dodajwpis(QAbstractItemModel *model, QString wpistyp, QString wpisnazwa, QString wpiszaw, QString wpiskraj)
{
    model->insertRow(0);
    model->setData(model->index(0,0),wpistyp);
    model->setData(model->index(0,1),wpisnazwa);
    model->setData(model->index(0,2),wpiszaw);
    model->setData(model->index(0,3),wpiskraj);
}

---

EGlowny derives from QMainWindow which already has a layout with a center widget, a dockable toolbar and menubar. The code you provided didn't compile, but what you need to do is to set up your layout on the centralWidget() instead of the main window. You could also derive EGlowny from a QWidget instead of a QMainWindow if you don't need the facilities of the QMainWindow.

Thank you. Problem solved