Buttons aren't showing

[AlaaM]

I'm trying to create a simple application with 4 buttons using QStackedWidget (1 screen, 4 buttons).
But the screen is showing empty (without the buttons). Here's the code:

main.cpp:

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

    MainWindow mainWindow;

    mainWindow.showFullScreen();
    return app.exec();
}

mainwindow.cpp:

#include "mainwindow.h"

QStackedWidget *stackedWidget;
QVBoxLayout *vLayout;

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{

    // Create widgets to populate the pages
    for(int i=0; i<BUTTONS_NUMBER; i++)
    {
        widgets[i] = new QWidget;
    }

    // Create buttons to navigate between the pages
    int x1Point = (WINDOW_WIDTH-ButtonWidth)/2;
    for(int i=0; i<BUTTONS_NUMBER; i++)
    {
        buttons[i] = new QPushButton(widgets[i]);
        buttons[i]->setText(tr("&abutton"));
        buttons[i]->setGeometry(QRect(QPoint(x1Point, ButtonHeight*0), QSize(ButtonWidth, ButtonHeight)));
        buttons[i]->show();
    }

    // Create stacked widget for the pages
    stackedWidget = new QStackedWidget;
    for(int i=0; i<BUTTONS_NUMBER; i++)
    {
        stackedWidget->addWidget(widgets[i]);
    }
    stackedWidget->setCurrentIndex(0);

    vLayout = new QVBoxLayout;
    vLayout->addWidget(stackedWidget);

//    setLayout(vLayout); //if enabled, it generates the error: "QWidget::setLayout: Attempting to set QLayout "" on MainWindow "", which already has a layout"
}

while both stackedWidget and vLayout are global variables declared in a separate *.h file as externs:

extern QStackedWidget *stackedWidget;
extern QVBoxLayout *vLayout;

and both widgets and buttons are private variables of MainWindow.
Here's mainwindow.h:

namespace Ui {
    class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    explicit MainWindow(QWidget *parent = 0);
    //...
    ~MainWindow(){}
private slots:
    //...
private:
    QWidget* widgets[BUTTONS_NUMBER];
    QPushButton* buttons[BUTTONS_NUMBER];
    const int ButtonWidth = 200;
    const int ButtonHeight = 50;
};

Only an empty window is shown (after executing mainWindow.showFullScreen() in main.cpp. But I need to show also the buttons.

[mrjj]

hi
QMainwindow already have layout to handle docking so it a bit special.
This code does show buttons.

MainWindow::MainWindow(QWidget* parent)
  : QMainWindow(parent) {
  resize(500, 500);

  // Create widgets to populate the pages
  for(int i = 0; i < BUTTONS_NUMBER; i++) {
    widgets[i] = new QWidget;  
  }

  // Create buttons to navigate between the pages
  int x1Point = (width() - ButtonWidth) / 2;
  for(int i = 0; i < BUTTONS_NUMBER; i++) {
    buttons[i] = new QPushButton(widgets[i]);
    buttons[i]->setText(tr("&abutton") + QString::number(i)); // give number for test
    buttons[i]->setGeometry(QRect(QPoint(x1Point, ButtonHeight * 0), QSize(ButtonWidth, ButtonHeight)));
    buttons[i]->show();
  }

  // Create stacked widget for the pages
  stackedWidget = new QStackedWidget();

  for(int i = 0; i < BUTTONS_NUMBER; i++) {
    stackedWidget->addWidget(widgets[i]);
  }
  stackedWidget->setCurrentIndex(0);

  setCentralWidget(stackedWidget);

}

[AlaaM]

So I'm only missingsetCentralWidget(stackedWidget);
Adding it worked. Thanks
BTW, I have a typo: ButtonHeight*0 should be ButtonHeight*i

[mrjj]

@AlaaM
Well , i did see it but button start in 0,0 perfect valid so did not think much about it.
Just added + QString::number(i) so when testing by changing
stackedWidget->setCurrentIndex(0);
I could see it was indeed another button :)