I have a class that composes a palette and assigns it to the application using QApplication::instance()->setPalette(QPalette palette)
.
And it effectively works.
But then I try to use QPalette QApplication::instance()->palette()
to extract some colours.
But here it does not work, it just returns the default palette, not the current one.
After I have discovered that it is working as supposed and described in the documentation.
And now I have just 2 questions:
QApplication::instance()->setPalette(QPalette palette)
?P.S. No, I can't keep that palette elsewhere.
I think it is an issue of your Qt version (you marked the question as Qt 5 but didn't indicate a specific version), or you have something else in your project that is resetting the palette (you mentioned it has a large code base).
This minimum example shows correct behavior, at least with Qt 5.12.3 32bits, Windows, VS 2017:
#include <QApplication>
#include <QPalette>
#include <QDebug>
#include <QTimer>
#include <QWidget>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
const auto group = QPalette::Active;
const auto role = QPalette::Text;
auto palette = QApplication::palette();
qDebug() << "palette before:" << palette.color(group, role).name();
palette.setColor(group, role, "#123456");
qDebug() << "palette set:" << palette.color(group, role).name();
QApplication::setPalette(palette);
const auto palette2 = QApplication::palette();
qDebug() << "palette after:" << palette2.color(group, role).name();
QTimer::singleShot(100, [=]() { // check palette after the events loop has started
const auto palette3 = QApplication::palette();
qDebug() << "palette after 100ms:" << palette3.color(group, role).name();
});
QWidget w;
w.show();
return a.exec();
}
I've used QApplication::palette
my self to retrieve custom palettes in different projects and had no issues at all.
QGuiApplication::setPalette
is documented to change the default palette, so basically I think default palette means the palette used if a widget doesn't specify the other one; not the default system palette.
PS: I couldn't make it compile when using QApplication::instance()->setPalette
since QApplication
doesn't defines instance()
but it falls to QCoreApplication::instance()
, which obviously returns a QCoreApplication
. Probably just a typo when you wrote the question, but I thought it deserved some lines. Given that the palette related methods are static, I decided to use those in the example, but I had the same results using the singleton from qApp
.
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