Qt FullScreen on Startup

Question

I want to start an application on fullscreen (MacOS 10.8.x, Qt 5.1.1, C++) depending on the settings:

main.cpp

#include "MainWindow.h" #include <QApplication>  int main(int argc, char *argv[]) {     QApplication a(argc, argv);     MainWindow w;     w.showFullScreen();      return a.exec(); } 

MainWindow.cpp

#include "MainWindow.h" #include "ui_MainWindow.h"  MainWindow::MainWindow(QWidget *parent) :     QMainWindow(parent),     ui(new Ui::MainWindow) {     ui->setupUi(this); }  MainWindow::~MainWindow() {     delete ui; } 

MainWindow.h

#ifndef MAINWINDOW_H #define MAINWINDOW_H  #include <QMainWindow>  namespace Ui { class MainWindow; }  class MainWindow : public QMainWindow {     Q_OBJECT  public:     explicit MainWindow(QWidget *parent = 0);     ~MainWindow();  private:     Ui::MainWindow *ui; };  #endif // MAINWINDOW_H 

The settings comportment is perfect, works like a charm. But this->showFullScreen() does something very ugly :

1. Display the window in fullscreen
2. Display the window in normal size in the center
3. Scale the window to fullscreen

How to avoid this?

Answer 1

I already faced this problem and a very nice solution was to delay the fullscreen switch by one second (using a QTimer):

QTimer::singleShot(0, this, SLOT(showFullScreen())); 

Answer 2

use the following if you want to have the app open as maximized window:

Mainwindow w; w.setWindowState(Qt::WindowMaximized); w.show(); 

use the following if you want to have the app open as fullscreen window:

Mainwindow w; w.setWindowState(Qt::WindowFullScreen); w.show();