changing window background color

jediapingveno

Hi,

I am trying to change the appearance of the windows produced by QT.

I tried using style sheets to change the background color of a window, as follows:

QApplication *app = new QApplication(argc, argv);

Control *control = new Control();
app->setStyleSheet("Control { background: black;} ");

That works until I add widgets to the control window. Then the window background becomes white again.

  auto *vbox = new QVBoxLayout();

  auto *btn1 = new QPushButton("button 1");
  vbox->addWidget(btn1);

  auto *lbl1 = new QLabel("label 1");
  vbox->addWidget(lbl1);

  setLayout(vbox);

How do I keep background color when I add buttons to the window?

Regards,

Jed

SGaist

Hi and welcome to devnet,

Can you provide a minimal compilable example that shows that behaviour ?

Which version of Qt is it ?
On which OS ?

jediapingveno

I am using manjaro linux with the XFCE desktop. QT version 5.15.2.

The three program files are as follows:

main.cpp:

#include <QApplication>
#include <QWidget>
#include "control.h"

int main(int argc, char **argv)
{
  QApplication *app = new QApplication(argc, argv);

  Control *control = new Control();

  QString style1 = "Control {background: black; } ";

  app->setStyleSheet(style1);

  control->move(500,300);
  control->setGeometry(300,300,400,500);

  control -> show();

  return app -> exec();
}

control.h:

#pragma once

#include <QWidget>
#include <QPushButton>

class Control : public QWidget
{
  Q_OBJECT
    
  public:
    Control(QWidget *parent = 0);
};

control.cpp:

#include "control.h"

#include <QVBoxLayout>
#include <QPushButton>
#include <QLabel>

Control::Control(QWidget *parent) : QWidget(parent)
{
  setWindowTitle("Control Window");

  auto *vbox = new QVBoxLayout();
/*
  // make buttons
  auto *btn1 = new QPushButton("button 1");
  vbox->addWidget(btn1);

  auto *btn2 = new QPushButton("button 2");
  vbox->addWidget(btn2);

  // make labels
  auto *lbl1 = new QLabel("label 1");
  vbox->addWidget(lbl1);
*/
  setLayout(vbox);
}

If this is compiled as is, the background is black, but if you add in the commented out code, the background reverts to white.

SGaist

It's working fine for me with the same version of Qt on macOS 10.13.6.

Is this the Qt version provided with your distribution ?