QPainter problem when trying to draw a push button on a toolbar.

[bigLuke09]

Hello, I'm new to Qt and using it for my thesis. This toolbar is utilized by a program called Paraview and I want to add functionality to it. When I try to add this push button below, it compiles fine, but I'm getting an error saying the painter isn't active. How do I enable it?

@MyToolBarActions::MyToolBarActions(QObject* p)
: QActionGroup(p)
{
QIcon icon = qApp->style()->standardIcon(QStyle::SP_MessageBoxCritical);
QStyleOptionButton opt;
opt.state = QStyle::State_Active | QStyle::State_Enabled;
opt.rect = QRect(50, 25, 100, 50);
QPainter painter;
painter.drawText(55, 30, 80, 30, Qt::AlignCenter, "MyAction");
painter.beginNativePainting();
qApp->style()->drawControl(QStyle::CE_PushButton,&opt,&painter);
painter.endNativePainting();
QAction* a = this->addAction(new QAction(icon, "MyAction", this));
//QAction* a2 = this->addAction(new QAction(icon2, "MyAction2",this));

QObject::connect(a, SIGNAL(triggered(bool)), this, SLOT(onAction()));
}@

Thanks much.

[mlong]

You can only use a painter during a widget's paintEvent(), not just anywhere to decorate an item.

Why are you trying to draw a push button? Why not just create a QToolButton and add it to the tool bar? Or better yet, just create your QAction and add it to the toolbar...

[steno]

You can't paint onto a widget outside of the paintEvent. I would suggest reading the documentation of QPainter, it will clear up a lot for you.

[bigLuke09]

Thanks, the documentation cleared that up and that part is pointless. Actually, I'm just trying to draw the button as an intermediate step. I've already created QActions with them. Ultimately, I want to add a QComboBox to the Toolbar with a bunch of items, but everything I've tried is failing, so I started simpler. Any suggestions on how to implement the QComboBox?

[steno]

Look into QWidgetAction. It allows you to put widgets into toolbars.

[mlong]

You can use "addWidget()":/doc/qt-4.8/qtoolbar.html#addWidget on the toolbar to add your QComboBox.

[bigLuke09]

Thank you. You have been very helpful.