Creating a widget AFTER the window has loaded :)

[aaron1a12]

Hi, so being a newbie at Qt (and a bit with C++) I've launched into this crazy DirectX project in Visual Studio using Qt. I don't like using the designer so I deleted my .UI file and ended up getting more control over my UI.h file. So now in my project I got 3 files:

1. studio.cpp
2. studio.h
3. EditorUI.h

(I combined my main.cpp into studio.cpp to make things simpler)

In my studio.cpp I have to create a custom DirectX widget but it has to be created AFTER the window has been loaded and created. So I added it to my entry point, like so:

//Show the main window
Studio MainWindow;
MainWindow.show();
 
 
//Create our DirectX widget
MainWindow.CreateViewport();

//Show the main window
Studio MainWindow;
MainWindow.show();


//Create our DirectX widget
MainWindow.CreateViewport();

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Right before the entry point I declare CreateViewport();

void Studio::CreateViewport()
{
	//Instead of creating the DirectX widget, let's see if we can create a simple button on runtime
	BtnInitDevice = new QPushButton(this);
	BtnInitDevice->setObjectName(QString::fromUtf8("BtnInitDevice"));
	BtnInitDevice->setGeometry(QRect(20, 545, 200, 23));
	BtnInitDevice->winId();
	BtnInitDevice->setText(QApplication::translate("StudioClass", "Initialize DirectX11 Device", 0, QApplication::UnicodeUTF8));
 
	/* DirectX widget
	//Aristos Portal
	MainViewport = new AristosPortal(this);
	MainViewport->PortalHandle = MainViewport->winId();
 
	MainViewport->setObjectName(QString::fromUtf8("MainViewport"));
	MainViewport->setGeometry(QRect(20, 60, 640, 480));
	MainViewport->setAutoFillBackground(false);
	MainViewport->setStyleSheet(QString::fromUtf8("background-color:red;"));
 
	//Must be after the window has been created!!!
	MainViewport->startAristos();
	*/
}

void Studio::CreateViewport()
{
	//Instead of creating the DirectX widget, let's see if we can create a simple button on runtime
	BtnInitDevice = new QPushButton(this);
	BtnInitDevice->setObjectName(QString::fromUtf8("BtnInitDevice"));
	BtnInitDevice->setGeometry(QRect(20, 545, 200, 23));
	BtnInitDevice->winId();
	BtnInitDevice->setText(QApplication::translate("StudioClass", "Initialize DirectX11 Device", 0, QApplication::UnicodeUTF8));

	/* DirectX widget
	//Aristos Portal
	MainViewport = new AristosPortal(this);
	MainViewport->PortalHandle = MainViewport->winId();

	MainViewport->setObjectName(QString::fromUtf8("MainViewport"));
	MainViewport->setGeometry(QRect(20, 60, 640, 480));
	MainViewport->setAutoFillBackground(false);
	MainViewport->setStyleSheet(QString::fromUtf8("background-color:red;"));

	//Must be after the window has been created!!!
	MainViewport->startAristos();
	*/
}

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As you can see in the code above, I didn't try to create the custom DirectX widget, instead I try to do a button.

This function gets executed right after MainWindow.show(); but it does not create the button! I also tried creating a QWidget window but it flashes and appears only for a split second, it then vanishes!

So my question is whether or not am I using the correct procedure to create a widget after the window has been created?

Many thanks,

PS: Here is my full code

studio.cpp

#include "studio.h"
#include <QtGui>
#include <QtGui/QApplication>
#include <QtGui/QWidget>
#include "AristosPortal.h"
 
//Some Declarations
QPushButton *BtnInitDevice;
AristosPortal *MainViewport;
 
 
Studio::Studio(QWidget *parent, Qt::WFlags flags)
	: QMainWindow(parent, flags)
{
	//Create the UI
	ui.setupUi(this);
 
}
 
 
//Tries to only create a button
void Studio::CreateViewport()
{
 
	BtnInitDevice = new QPushButton(this);
	BtnInitDevice->setObjectName(QString::fromUtf8("BtnInitDevice"));
	BtnInitDevice->setGeometry(QRect(20, 545, 200, 23));
	BtnInitDevice->winId();
	BtnInitDevice->setText(QApplication::translate("StudioClass", "Initialize DirectX11 Device", 0, QApplication::UnicodeUTF8));
 
	/*
	//Aristos Portal
	MainViewport = new AristosPortal(this);
	MainViewport->PortalHandle = MainViewport->winId();
 
	MainViewport->setObjectName(QString::fromUtf8("MainViewport"));
	MainViewport->setGeometry(QRect(20, 60, 640, 480));
	MainViewport->setAutoFillBackground(false);
	MainViewport->setStyleSheet(QString::fromUtf8("background-color:red;"));
 
	//Must be after the window has been created!!!
	MainViewport->startAristos();
	*/
}
 
Studio::~Studio()
{
//Fires when the app closes?
}
 
 
 
//Entry point to the applicaton
 
int main(int argc, char *argv[])	
{
	QApplication::setStyle(new QPlastiqueStyle);
	QApplication a(argc, argv);
 
 
	Studio MainWindow;
	MainWindow.show();
 
 
	//Create our viewport (or button, whatever)
	MainWindow.CreateViewport();
 
	// This creates a window that flashes. Why? Why!?
	//QWidget MyWidget;
	//MyWidget.show();
 
 
	return a.exec();
}

#include "studio.h"
#include <QtGui>
#include <QtGui/QApplication>
#include <QtGui/QWidget>
#include "AristosPortal.h"

//Some Declarations
QPushButton *BtnInitDevice;
AristosPortal *MainViewport;


Studio::Studio(QWidget *parent, Qt::WFlags flags)
	: QMainWindow(parent, flags)
{
	//Create the UI
	ui.setupUi(this);

}


//Tries to only create a button
void Studio::CreateViewport()
{

	BtnInitDevice = new QPushButton(this);
	BtnInitDevice->setObjectName(QString::fromUtf8("BtnInitDevice"));
	BtnInitDevice->setGeometry(QRect(20, 545, 200, 23));
	BtnInitDevice->winId();
	BtnInitDevice->setText(QApplication::translate("StudioClass", "Initialize DirectX11 Device", 0, QApplication::UnicodeUTF8));

	/*
	//Aristos Portal
	MainViewport = new AristosPortal(this);
	MainViewport->PortalHandle = MainViewport->winId();

	MainViewport->setObjectName(QString::fromUtf8("MainViewport"));
	MainViewport->setGeometry(QRect(20, 60, 640, 480));
	MainViewport->setAutoFillBackground(false);
	MainViewport->setStyleSheet(QString::fromUtf8("background-color:red;"));

	//Must be after the window has been created!!!
	MainViewport->startAristos();
	*/
}

Studio::~Studio()
{
//Fires when the app closes?
}



//Entry point to the applicaton

int main(int argc, char *argv[])	
{
	QApplication::setStyle(new QPlastiqueStyle);
	QApplication a(argc, argv);


	Studio MainWindow;
	MainWindow.show();


	//Create our viewport (or button, whatever)
	MainWindow.CreateViewport();

	// This creates a window that flashes. Why? Why!?
	//QWidget MyWidget;
	//MyWidget.show();


	return a.exec();
}

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studio.h

#ifndef STUDIO_H
#define STUDIO_H
 
#include <QtGui/QMainWindow>
 
 
#include "EditorUI.h"
 
 
class Studio : public QMainWindow
{
	Q_OBJECT
 
public:
	Studio(QWidget *parent = 0, Qt::WFlags flags = 0);
	~Studio();
	void CreateViewport();
 
 
 
 
private:
	Ui::StudioClass ui;
 
};
 
#endif // STUDIO_H

#ifndef STUDIO_H
#define STUDIO_H

#include <QtGui/QMainWindow>


#include "EditorUI.h"


class Studio : public QMainWindow
{
	Q_OBJECT

public:
	Studio(QWidget *parent = 0, Qt::WFlags flags = 0);
	~Studio();
	void CreateViewport();


	

private:
	Ui::StudioClass ui;

};

#endif // STUDIO_H

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[ChrisW67]

Sure it creates the QPushButton object. However, your code does not show() that widget or add to the layout of a widget that is already being shown (whatever it is that setupUi() builds). Consequently, the widget is not visible.

Other notes:

• The declarations at lines 8-9 of your CPP files should be member variables of the Studio class.
• Line 28 of your cpp file listing is probably pointless.

[aaron1a12]

Thank you so much! I didn't know you add to "show" or "add" the widget to something. I just thought that if you provided the window or widget handle at it's creation it would create it as a child window to that handle.

BTW: Line 28 makes Qt draw the widgets as windows so each one has a window handle. It's necessary for directX