Change Background Color specific QSplitter Child - c++

Question

I am using Qt Creator 4.13.1 with Qt 5.15.1 on Windows 10 Pro.
I am new to using Stylesheets in Qt and a bit confused of the possible selectors considering QSplitter and its child. I want to have 2 childs separated by a splitter-handle and draw their backgrounds in different colors.
This is an example szenario
QSplitter* splitter = new QSplitter();
QWidget* widgetA = new QWidget();
// add a layout with some further child widgets
QWidget* widgetB = new QWidget();
// add a layout with some further child widgets
splitter->addWidget(widgetA);
splitter->addWidget(widgetB);
layout()->addWidget(splitter);
where I tried:
widgetA->setStyleSheet("background-color: #ff0000;"); which applies to all child widgets of widgetA (e.g. QLabels, QPushButtons, ...) , but not to their surrounding widgetA itself
splitter->setStyleSheet("background-color: #ff0000;"); applies to the widgetA, widgetB and the handle and all widgets below widgetA and widgetB
naming widgetA->setObjectName("Tim"); and splitter->setStyleSheet("QWidget#Tim {background-color: #ff0000;}"); which has no effect at all.
[EDIT] splitter->setStyleSheet("QSplitter QWidget #Andy {background-color: #ff0000;}"); applies the background only to a certain widget inside either child widget. But using splitter->setStyleSheet("QSplitter #Tim {background-color: #ff0000;}"); has (again) no effect at all.
How would I set the background-color of widgetA separately, so without affecting the childs of widgetA or the other splitter child widgetB?

Answer 1

I don't see any problems with using widget->setStyleSheet() in your case. Here, I have tested your implementation of setObjectName():
Application::Application(QWidget *parent) :
QWidget(parent)
{
//set a base layout for the parent of splitter
QHBoxLayout *boxLayout = new QHBoxLayout(this);
this->setLayout(boxLayout);
//allocate splitter with parent
QSplitter* splitter = new QSplitter(this);
QWidget* widgetA = new QWidget();
widgetA->setObjectName("widgetA");
widgetA->setLayout(new QVBoxLayout());
//example buttons as child for widgetA
QPushButton *p = new QPushButton("0",widgetA);
widgetA->layout()->addWidget(p);
p = new QPushButton("1",widgetA);
widgetA->layout()->addWidget(p);
p = new QPushButton("2",widgetA);
widgetA->layout()->addWidget(p);
p = new QPushButton("3",widgetA);
widgetA->layout()->addWidget(p);
//widgetB, all similar to widgetA
QWidget* widgetB = new QWidget();
widgetB->setObjectName("widgetB");
widgetB->setLayout(new QVBoxLayout());
widgetA->setStyleSheet("QWidget#widgetA{background-color: #ff0000;}");
widgetB->setStyleSheet("QWidget#widgetB{background-color: #00ff00;}");
p = new QPushButton("1",widgetB);
widgetB->layout()->addWidget(p);
p = new QPushButton("2",widgetB);
widgetB->layout()->addWidget(p);
p = new QPushButton("3",widgetB);
widgetB->layout()->addWidget(p);
//add both widgets to splitter
splitter->addWidget(widgetA);
splitter->addWidget(widgetB);
//add splitter to base layout
this->layout()->addWidget(splitter);
}
Output