Shrinking for QDialog with QStackedWidget in it is not working

Kelly Ryan

This is my simple dialog without QStackedWidget:

MyDialog::MyDialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::MyDialog)
{
    ui->setupUi(this);

    ShowFrame(false);

    connect(ui->checkBox, &QCheckBox::toggled, this, [this](bool checked) {
        ShowFrame(checked);
    });
}

void MyDialog::ShowFrame(bool isHidden)
{
    ui->frame->setVisible(isHidden);
    adjustSize();
}

And it works fine. Whenever I press the checkbox the dialog grows/shrinks.

But after I add QStackedWidget in QDialog, shrinking is not working anymore.

Starts like this:
Then grows after pressing the checkbox:
And never shrinks back:

Here's the updated dialog with QStackedWidget:

MyDialogWithStackedWidget::MyDialogWithStackedWidget(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::MyDialogWithStackedWidget)
{
    ui->setupUi(this);

    ShowFrame(false);

    connect(ui->checkBox, &QCheckBox::toggled, this, [this](bool checked) {
        ShowFrame(checked);
    });
}

void MyDialogWithStackedWidget::ShowFrame(bool isShown)
{
    ui->frame->setVisible(isShown);
    ui->stackedWidget->adjustSize();
    adjustSize();
}

What am I missing?

JoeCFD

@Kelly-Ryan said in Shrinking for QDialog with QStackedWidget in it is not working:

void MyDialog::ShowFrame(bool isHidden)
{
ui->frame->setVisible(isHidden);
adjustSize();
}

https://stackoverflow.com/questions/14480696/resize-qstackedwidget-to-the-page-which-is-opened

Kelly Ryan

I made ResizableStackedWidget:

ResizableStackedWidget::ResizableStackedWidget(QWidget *parent) : QStackedWidget(parent)
{
	connect(this, &ResizableStackedWidget::currentChanged, this, [this](int index) {
		QWidget* pWidget = widget(index);
		Q_ASSERT(pWidget);
		pWidget->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
		pWidget->adjustSize();
		adjustSize();
	});
}

int ResizableStackedWidget::addWidget(QWidget* pWidget)
{
   pWidget->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
   return QStackedWidget::addWidget(pWidget);
}

And promoted my old QStackedWidget to this new one.

On dialog creation ResizableStackedWidget::addWidget is called with page and page_2 widgets.
Also currentChanged is triggered with index = 0.
So at the end we have:
page = Expanding, Expanding
page_2 = Ignored, Ignored
It doesn't help me. My QDialog is still not shrinking after the frame is hidden.

I've read about the resizable stacked widget and it doesn't seem to be what I want. It's resized whenever you change the pages of QStackedWidget.
My issue is that after some widget is hidden the whole dialog is not resized to fit minimum space. It doesn't even get Resize event. And it's not about changing pages. I don't even change them, I'm always on 1st page. The problem is only about QDialog resizing.

Perhaps, I've missed something, sorry.

Kelly Ryan

"MyDialog" 	=	 QEvent::Resize // <-- here it grows before showing the frame
"frame" 	=	 QEvent::Move
"frame" 	=	 QEvent::Resize
"frame" 	=	 QEvent::Show
"frame" 	=	 QEvent::ShowToParent
"MyDialog" 	=	 QEvent::UpdateRequest
"MyDialog" 	=	 QEvent::Paint
"frame" 	=	 QEvent::Paint
"MyDialog" 	=	 QEvent::LayoutRequest
"frame" 	=	 QEvent::UpdateLater
"MyDialog" 	=	 QEvent::UpdateRequest
"MyDialog" 	=	 QEvent::Paint
"frame" 	=	 QEvent::Paint
"MyDialog" 	=	 QEvent::UpdateRequest
"MyDialog" 	=	 QEvent::Paint
"MyDialog" 	=	 QEvent::UpdateRequest
"frame" 	=	 QEvent::Hide
"frame" 	=	 QEvent::HideToParent
"MyDialog" 	=	 QEvent::Resize  // here it shrinks after the frame is hidden

"MyDialogWithStackedWidget" 	=	 QEvent::Resize // <-- grows before showing the frame
"frame" 			=	 QEvent::Move
"frame" 			=	 QEvent::Resize
"frame" 			=	 QEvent::Show
"frame" 			=	 QEvent::ShowToParent
"MyDialogWithStackedWidget" 	=	 QEvent::UpdateRequest
"MyDialogWithStackedWidget" 	=	 QEvent::Paint
"stackedWidget" 		=	 QEvent::Paint
"frame" 			=	 QEvent::Paint
"stackedWidget" 		=	 QEvent::LayoutRequest
"MyDialogWithStackedWidget" 	=	 QEvent::LayoutRequest
"frame" 			=	 QEvent::UpdateLater
"MyDialogWithStackedWidget" 	=	 QEvent::UpdateRequest
"MyDialogWithStackedWidget" 	=	 QEvent::Paint
"stackedWidget" 		=	 QEvent::Paint
"frame" 			=	 QEvent::Paint
"MyDialogWithStackedWidget" 	=	 QEvent::UpdateRequest
"MyDialogWithStackedWidget" 	=	 QEvent::Paint
"stackedWidget" 		=	 QEvent::Paint
"MyDialogWithStackedWidget" 	=	 QEvent::UpdateRequest
"frame" 			=	 QEvent::Hide
"frame" 			=	 QEvent::HideToParent
"stackedWidget" 		=	 QEvent::Resize // <-- only the stacked widget gets resize event and properly shrinks
"MyDialogWithStackedWidget" 	=	 QEvent::UpdateRequest
"MyDialogWithStackedWidget" 	=	 QEvent::Paint
// the dialog never shrinks after the frame is hidden (never gets resize event)

Kelly Ryan

MyDialog was getting the resize event after its contents were changed.
In MyDialogWithStackedWidget the stacked widget now gets that resize event after its contents are changed and it feels like it just doesn't propagate it to its parent, no?

Kelly Ryan

Okay, I managed to make it work like this:

void MyDialogWithStackedWidget::ShowFrame(bool isShown)
{
	ui->frame->setVisible(isShown);
	ui->stackedWidget->currentWidget()->adjustSize();
	ui->stackedWidget->adjustSize();
	adjustSize();
}

And setting size policies for current active page (stackedWidget->currentWidget), stackWidget and dialog itself to Fixed/Fixed.

Perhaps, that's what @JoeCFD meant in the first place and I just didn't get it.