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Centering a QToolButton in a QVBoxLayout?



  • It appears that QVBoxLayout's setAlignment(Qt::AlignHCenter) only sudo centres the widgets (or only the widest one). The smaller QToolButton is left aligned with the left edge of widest widget.
    0_1512583094832_wrong.png
    Is this a bug in QVBoxLayout or am I doing somehing wrong? QGridLayout (below) works fine. Code that made above image....

    test.pro

    QT+= core gui widgets
    TARGET = test
    TEMPLATE = app
    SOURCES+= main.cpp
    

    main.cpp

    #include <QWidget>
    #include <QVBoxLayout>
    #include <QToolButton>
    #include <QApplication>
    #include <QStyle>
    
    int main(int argc, char *argv[])
    {
    	QApplication a(argc, argv);
    
    	QWidget *window = new QWidget();
    	QVBoxLayout *layout = new QVBoxLayout();
    	QToolButton *button;
    
    	layout->setAlignment(Qt::AlignHCenter);
    
    	layout->addStretch();
    
    	button = new QToolButton();
    	button->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);
    	button->setIcon(window->style()->standardIcon(QStyle::SP_BrowserReload));
    	button->setIconSize(QSize(25,25));
    	button->setText("Short");
    	//button->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Maximum);
    	layout->addWidget(button);
    
    	layout->addStretch();
    
    	button = new QToolButton();
    	button->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);
    	button->setIcon(window->style()->standardIcon(QStyle::SP_BrowserReload));
    	button->setIconSize(QSize(25,25));
    	button->setText("Long Long Long Long Long");
    	//button->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Maximum);
    	layout->addWidget(button);
    
    	layout->addStretch();
    
    	window->setLayout(layout);
    	window->show();
    
    	return a.exec();
    }
    

    QGridLayout works fine....
    0_1512582172066_right.png
    Code that made this below....

    #include <QWidget>
    #include <QGridLayout>
    #include <QToolButton>
    #include <QApplication>
    #include <QStyle>
    
    int main(int argc, char *argv[])
    {
    	QApplication a(argc, argv);
    
    	QWidget *window = new QWidget();
    	QGridLayout *layout = new QGridLayout();
    	QToolButton *button;
    
    	//layout->setAlignment(Qt::AlignHCenter);  // does nothing
    
    	layout->setRowStretch(0, 1);
    	layout->setRowStretch(2, 1);
    	layout->setRowStretch(4, 1);
    	layout->setColumnStretch(0, 1);
    	layout->setColumnStretch(2, 1);
    
    	button = new QToolButton();
    	button->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);
    	button->setIcon(window->style()->standardIcon(QStyle::SP_BrowserReload));
    	button->setIconSize(QSize(25,25));
    	button->setText("Short");
    	layout->addWidget(button, 1, 1, Qt::AlignHCenter);
    
    	button = new QToolButton();
    	button->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);
    	button->setIcon(window->style()->standardIcon(QStyle::SP_BrowserReload));
    	button->setIconSize(QSize(25,25));
    	button->setText("Long Long Long Long Long");
    	layout->addWidget(button, 3, 1, Qt::AlignHCenter);
    
    	window->setLayout(layout);
    	window->show();
    
    	return a.exec();
    }
    


  • Hi @drwho

    The problem is with this line :

    layout->setAlignment(Qt::AlignHCenter);

    You are calling this function before the addWidget function, and i think that with vertialLayout to use AlignHCenter , you need to tell which item you need to center,

    -just put setAlignement after the addWidget, and use setAlignement(button, Qt::AlignHCenter) instead of setAlgnement(Qt::AlignHCenter);

    You code should look to something like this:

    QWidget *window = new QWidget();
        QVBoxLayout *layout = new QVBoxLayout();
        QToolButton *button;
    
        layout->addStretch();
    
        button = new QToolButton();
        button->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);
        button->setIcon(window->style()->standardIcon(QStyle::SP_BrowserReload));
        button->setIconSize(QSize(25,25));
        button->setText("Short");
        //button->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Maximum);
        layout->addWidget(button);
        layout->setAlignment(button, Qt::AlignHCenter);// Call setAlignement(button, Qt::AlignHCenter) after addWidget
        layout->addStretch();
    
        button = new QToolButton();
        button->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);
        button->setIcon(window->style()->standardIcon(QStyle::SP_BrowserReload));
        button->setIconSize(QSize(25,25));
        button->setText("Long Long Long Long Long");
        //button->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Maximum);
        layout->addWidget(button);
        layout->setAlignment(button, Qt::AlignHCenter);// Call setAlignement(button, Qt::AlignHCenter) after addWidget
        layout->addStretch();
    
        window->setLayout(layout);
        window->show();
    

    I hope this can help you !



  • Yes, setAlignment(button, Qt::AlignHCenter) does the trick. Thanks! It is too bad the alignment parameter in QVBoxLayout's addWidget() doesn't do this like QGridLayout's addWidget() does.


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