Toolbar spacer does not expand to the right corner

[TommyTLC]

Hello everyone this is my first post,

I have been trying to set some of my items to the right of a toolbar. By searching for a solution I understand that the general methodology would be to create a spacer and set its size policy to Expanding. However by doing so I am only able to create a small gap between my items(shown between Configuration and Style):

If I try to change its minimum size I apparently obtain my expected result, but this has the format I want only in full-screen.

If I try resizing the window, the items to the right of the toolbar disappear and therefore the spacer does not adjust to the correct size, keeping the items to the right hidden.

This is how I set up my spacer:

QWidget* spacer = new QWidget();
spacer->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Preferred);
spacer->setMinimumWidth(1180);
m_fileToolBar->addWidget(spacer);

My main goal is to have all items showing up in the toolbar no matter the window size.
Could someone please help me? Thank you all in advance. (I'm working with C++)

[JonB]

@TommyTLC
Maybe you need it because you are using a toolbar, I don't know. but why are you using a QWidget* spacer? Should/can you use a layout on the toolbar and use QSpacerItem, or more generally just QBoxLayout::addSpacing()? Maybe @VRonin's post at https://forum.qt.io/topic/65574/qtoolbar-widgets-spacing/2 indicates the approach?

[TommyTLC]

@JonB Thank you for your reply. I have tried applying @VRonin 's method, but the situation that is created is still the same: some space is added to the toolbar, but the items to the far right are hidden when the window is not in full-screen.

How would the other process you mentioned work? I have created a QSpacerItem this way:

QSpacerItem* spacerItem;
spacerItem->addSpacing();

But I am not able to use addSpacing() as it's not a member of QSpacerItem.

[VRonin]

Can't replicate the problem using Qt 5.15 or 6.0
See minimal example below:

#include <QApplication>
#include <QMainWindow>
#include <QToolBar>
#include <QLabel>
#include <QSpinBox>
#include <QLineEdit>
#include <QComboBox>
int main(int argc, char *argv[])
{
    QApplication app(argc,argv);
    QMainWindow wid;
    QToolBar* toolBar = new QToolBar;
    toolBar->addWidget(new QLabel("3DViewver"));
    toolBar->addWidget(new QLineEdit);
    toolBar->addWidget(new QLabel("OpenGL"));
    toolBar->addWidget(new QSpinBox);
    toolBar->addWidget(new QLabel("Configuration"));
    QWidget* spacer = new QWidget();
    spacer->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    toolBar->addWidget(spacer);
    toolBar->addWidget(new QLabel("Style"));
    toolBar->addWidget(new QComboBox);
    wid.addToolBar(toolBar);
    wid.show();
    return app.exec();
}

[TommyTLC]

Another method I have tried to fix my problem with is having 2 toolbars; one with the left-to-right items and another one with the right-to-lefts ones. The issue I'm having with this is being able to dock toolbar2 to the right of toolbar1 so that they can both be on the same line. I can dock toolbar2 to the Top, but that means having it right below toolbar1. The problem here is not being able to specify the docking area by comparing the two toolbars.

[TommyTLC]

@VRonin Thanks for your reply. Unfortunately I am still having the same issue where generating a spacer widget only adds a little bit of space between the items in the toolbar.

[VRonin]

1. Did you try the minimal example above?
2. What version of Qt are you using?
3. Do you customise any of the widgets on the right of the spacer?
   • if you give QSizePolicy::Expanding or minimum sizes to them they will be respected

[TommyTLC]

@VRonin I did try to include the spacer just like you do in your minimal example, but the problem is still there, therefore the issue might be somewhere else. I am working with Qt version 5.15.

This is all I have to the right of the spacer:

m_fileToolBar->addWidget(new QLabel(tr("   Style:")));
QAction* stylesAction = m_fileToolBar->addWidget(createComboBoxStyle());
stylesAction->setToolTip(tr("Styles switcher"));

m_fileToolBar->addSeparator(); 
m_fileToolBar->addAction(m_aboutAction);

Where m_fileToolBar is my toolBar and 2 actions as well as a separator and a label are added (these can be seen in the picture included in the original post).

[VRonin]

I suspect the problem is not with the spacer widget but with something else in your code.
We need to narrow down the list of suspects.
Please answer the point 1 above and, in addition:

4. what is the body of createComboBoxStyle?
5. how do you create m_aboutAction?

[mrjj]

Hi
Just as a note.
You could apply a style sheet

spacer->setStyleSheet("QWidget{ background-color: rgb(178, 255, 34);}");

so its clear how it's placed.

[TommyTLC]

@VRonin ok so I have tried creating a new project with your minimal example and that works perfectly! The problem is now understanding what's causing the issue in my project.

4. m_styleSwitcher = new QComboBox(this);
   m_styleSwitcher->addItem(m_defaultStyleAction->text(), Default);
   m_styleSwitcher->addItem(m_fusionStyleAction->text(), Fusion);
   m_styleSwitcher->addItem(QStringLiteral("VisualStudio2019 ") + m_themeBlueAction->text(), VS2019Blue);
   m_styleSwitcher->addItem(QStringLiteral("VisualStudio2019 ") + m_themeDarkAction->text(), VS2019Dark);
   m_styleSwitcher->addItem(QStringLiteral("VisualStudio2019 ") + m_themeLightAction->text(), VS2019Light);
   m_styleSwitcher->setCurrentIndex(static_cast<int>(m_appStyle));
   connect(m_styleSwitcher, SIGNAL(currentIndexChanged(int)), this, SLOT(styleIndexChanged(int)));
   return m_styleSwitcher;

5. m_aboutAction is created in the .h file:

   QAction* m_aboutAction;

[TommyTLC]

@mrjj This might actually help understanding the cause of the issue. I have applied the style sheet to the spacer. When the window is in full screen mode I can correctly see the spacer object:

While having the application in a smaller window I do not see the style sheet:

[mrjj]

@TommyTLC
Ok so does it go into the >> or is then completely gone ?

[TommyTLC]

@mrjj in the >> I only see my m_aboutAction. It looks like the spacer disappears when the application is not in full screen.

[mrjj]

@TommyTLC
That i have not seen before. :)
Could you give your spacer object a name with setObjectName and
then do
ui->menubar->dumpObjectTree();
(adjust to name)

Then it will show all its sub objexts like

QMenuBar::menubar 
    QToolButton::qt_menubar_ext_button 
    QMenu::menuMENU 
        QAction:: 
    QMenu::menuMENU2 
        QAction:: 
    QMenu::menuMENU3 
        QAction:: 

just to see if its still in or really gone. Its kinda hard for a widget to just fall off as it's owned by the parent.

[TommyTLC]

@mrjj This is what I have done:

spacer->setObjectName("spacerName");
ui->m_fileToolBar->dumpObjectTree();

It looks like this function does not allow the use of "ui". If I follow the error's suggestion and use a pointer type toward m_fileToolBar I get another error saying that m_fileToolBar is not a member of the Ui::MainWindow class.

[mrjj]

Hi
the name m_fileToolBar suggest to me its not in a UI
so its just
m_fileToolBar->dumpObjectTree();

[TommyTLC]

@mrjj Thank you! Here's the output (I have given my spacer object the name "spacerName"):

Qtitan::DockToolBar::
Qtitan::DockToolBarLayout::
Qtitan::DockToolBarExtension::
QMenu::
QAction::
Qtitan::ToolButton::
QWidgetAction::
QLineEdit::
QWidgetLineControl::
Qtitan::ToolButton::
QWidgetAction::
QSpinBox::
QLineEdit::qt_spinbox_lineedit
QWidgetLineControl::
QValidator::qt_spinboxvalidator
Qtitan::ToolButton::
QWidgetAction::
QWidget::spacerName

[mrjj]

@TommyTLC
Ok so it is still there :)
Then i would
qDebug() << "size" << qDebug() << spacer->geometry();
and it will show something like
QRect(747,339 75x23)

as it could be fun to see its location and size.

[TommyTLC]

@mrjj This is where my spacer is located/its size: QRect(0,0 1180x480)