Why does the child widget not resize when I call resize () on parent?

[xruck]

There is CurveWidgetDialog derived form QDialog and QWidget curveWidget as child (attached picture).

I call method resize() in constructor of CurveWidgetDialog, but child widget ()curveWidget doesn't change size (qDebug() outputs "QSize(100, 30)"). I use folowing code:

CurveWidgetDialog::CurveWidgetDialog(QWidget *parent) :
	QDialog(parent),
	ui(new Ui::CurveWidgetDialog)
{
	ui->setupUi(this);
//...
	resize(1000, 1000);

	qDebug() << ui->curveWidget->size();
//...
}

what the hell?

[JonB]

@xruck
I assume the reason is: What size settings do you have on your CurveWidget which tell it you'd like it to occupy the full size of its parent QDialog?

Otherwise: It's just possible that resizing in the parent's constructor is too early for the child, though I don't think so.

[xruck]

Do you mean sizePolicy?

[mrjj]

Hi
Some layout calculation is postponed until widget is shown meaning
qDebug() << ui->curveWidget->size(); in constructor does not show the new size values.

So does it visually also NOT use all the space ?
When CurveWidgetDialog is actually shown on screen.

[xruck]

@mrjj
I create and show dialog in the main.cpp

int main(int argc, char *argv[])
{
	QApplication a(argc, argv);

	CurveWidgetDialog w;
	w.show();

	return a.exec();
}

I suppose I need handle QWidget::showEvent() signal to recive size of the widget?

[mrjj]

@xruck
Yes showEvent should give true size.
So it does use the actual space when shown, and its just the size reporting that is off ?

[xruck]

@mrjj Yeah! Fantasstic answer!! Thank you very much!:) We close question [EDIT: Expletives removed --JKSH]