QMainWindow does not show Qwidgets background

Question

I have a problem regarding a QWidget (custom made) inside a QMainWindow (custom made). My problem is that when I add my widget to my window as its central widget using setCentralWidget() method, it won't show the widgets background. It's important to show the background correctly. Here is my MyWindow.cpp code:

#include "MyMainWindow.h"

MyMainWindow::MyMainWindow(QWidget * parent, Qt::WindowFlags flag) :
        QMainWindow(parent, flag)
{
    this->setFixedSize(1120, 630);
    menu = new MyMenu(this);
//    setting = new MySetting();
//    tutorial = new MyTutorial();
//    game = new MyGame();
    this->setCentralWidget(menu);
    this->show();
}

MyMainWindow::~MyMainWindow()
{
}

My MyMenu.cpp code:

#include "MyMenu.h"

MyMenu::MyMenu(QWidget *parent, Qt::WindowFlags f) :
        QWidget(parent, f)
{
    this->resize(1120, 630);
    this->set_background();
    this->construct_buttons();
    this->construct_menu();
}

MyMenu::~MyMenu()
{
    delete start;
    delete setting;
    delete tutorial;
    delete exit;
    delete buttons;
    delete logo;
    delete menu;
}

void MyMenu::construct_menu()
{
    menu = new QVBoxLayout(this);
    logo = new QLabel(this);
    QPixmap *pixmap = new QPixmap("/home/kahrabian/ClionProjects/Shooter-AP93UT/Contents/logo.png");
    logo->setPixmap(*pixmap);
    logo->setAlignment(Qt::AlignHCenter);
    menu->addWidget(logo);
    menu->addLayout(buttons);
    delete pixmap;
}

void MyMenu::construct_buttons()
{
    buttons = new QHBoxLayout();
    start = new QPushButton("Start", this);
    buttons->addWidget(start);
    setting = new QPushButton("Setting", this);
    buttons->addWidget(setting);
    tutorial = new QPushButton("Tutorial", this);
    buttons->addWidget(tutorial);
    exit = new QPushButton("Exit", this);
    buttons->addWidget(exit);
}

void MyMenu::set_background()
{
    QPalette *palette = new QPalette();
    palette->setBrush(this->backgroundRole(),QBrush(QImage("/home/kahrabian/ClionProjects/Shooter-AP93UT/Contents/background_menu.jpg")));
    this->setPalette(*palette);
    delete palette;
}

My main.cpp code:

#include <QApplication>
#include "MyMenu.h"
#include "MyMainWindow.h"

int main(int argc, char **argv)
{
    QApplication app (argc, argv);
    MyMainWindow *mainwin = new MyMainWindow();
//    MyMenu *MyMenu = new MyMenu();
//    MyMenu->show();
    return app.exec();
}

Can anyone help me with this problem??

rsht · Accepted Answer · 2016-01-26T14:09:28.483

1

Check this answer.

I would recommend you to use Qt style sheets.

You would need to call something like this:

setStyleSheet("image: url(path/to/background/image.png);");

on your widget.

Also, you might need to implement paintEvent() for widget to accept style sheets.
I'm usually doing it like this:

void MyWidget::paintEvent(QPaintEvent *pe)
{    
    QStyleOption opt;
    opt.init(this);
    QPainter p(this);
    style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);

    QWidget::paintEvent(pe);
}

edited Jan 26 '16 at 14:09

answered Jul 04 '15 at 13:08

rsht

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27

thank you, but this answer does not generate the desired answer, it changes the background but it also changes the buttons shape. can you provide me with somthing similar to implementation that I have used?? it generates the desired answer until I add the widget as a central widget to my MainWindow (I can't understand why) – Kian Ahrabian Jul 04 '15 at 15:04
I would suggest trying "border-image" or "image" instead of "background-image" in style sheet. Look [here](http://doc.qt.io/qt-5/stylesheet-customizing.html#box-model) for more information. Also you could try providing same `paintEvent()` implementation for your `MyMainWindow` class. I can't try your code myself now, although I might be able to do that later today. – rsht Jul 04 '15 at 15:13
thank you very much, it works fine now. I used "image" instead of "background-image" also I deleted paintEvent(). it works fine without it :-) – Kian Ahrabian Jul 04 '15 at 15:24
No problem, mate. I'm glad that helps. Also, I have edited my answer according to your response. – rsht Jul 04 '15 at 15:32

QMainWindow does not show Qwidgets background

1 Answers1