Adjust mainwindow size when sub widget is hidden

akikaede

Hi, there, I'm writing a qt program and trying to resize mainwindow when sub widget is hidden, but there's some difference in Linux and Windows, and I don't know the property way to adjust size in both. Here's my minimum code:

// MainWindow
    MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    QWidget *mainWidget = new QWidget(this);
    QVBoxLayout *mainlayout = new QVBoxLayout(mainWidget);
    QPushButton *hide = new QPushButton(mainWidget);
    subwidget *sub = new subwidget(mainWidget);
    mainlayout->addWidget(hide);
    mainlayout->addWidget(sub);
    connect(hide, &QPushButton::clicked, sub, &subwidget::onHide);
    setCentralWidget(mainWidget);
    adjustSize();
    connect(hide, &QPushButton::clicked, this, [&] {
        QTimer::singleShot(0, this, [&] { adjustSize(); });
    });
}

// Widget
subwidget::subwidget(QWidget *parent)
    : QWidget{parent}
{
    QVBoxLayout *vlayout = new QVBoxLayout(this);
    QPushButton *btn1 = new QPushButton();
    btn2 = new QPushButton();
    vlayout->addWidget(btn1);
    vlayout->addWidget(btn2);
}

void subwidget::onHide()
{
    btn2->hide();
}

When I set the timer interval to 1, mainwindow will be the adjusted size when btn2 is hidden in Linux, but it doesn't work in Windows. How can I adjust the mainwindow in windows?

PS: I have tried to add a signal when subwidget is hidden and connect it to adjustSize like connect(sub, &subwidget::hidden, this, [&] { adjustSize(); });, but it also doesn't work.

mpergand

@akikaede

On MacOS, adjustSize has no effect until mainwidow is shown.

void MainWindow::show()
{
    QMainWindow::show();
    adjustSize();
}

[EDIT] I end up with this:

class subwidget : public QFrame
{
    public:
subwidget(QWidget *parent): QFrame{parent}
{
    setFrameShape(QFrame::Box);
    QVBoxLayout *vlayout = new QVBoxLayout(this);
    QPushButton *btn1 = new QPushButton();
    btn2 = new QPushButton();
    vlayout->addWidget(btn1);
    vlayout->addWidget(btn2);
}

void onHide()
{
    btn2->setVisible(!btn2->isVisible());
    adjustSize();
}

    QPushButton* btn2;
};

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    QWidget *mainWidget = new QWidget(this);
    QVBoxLayout *mainlayout = new QVBoxLayout(mainWidget);
    QPushButton *hide = new QPushButton(mainWidget);
    hide->setFixedSize(200,200);
    subwidget *sub = new subwidget(mainWidget);
    mainlayout->addWidget(hide);
    mainlayout->addWidget(sub);
    mainlayout->addStretch(0);
    connect(hide, &QPushButton::clicked, sub, &subwidget::onHide);
    setCentralWidget(mainWidget);

    connect(hide, &QPushButton::clicked, this, [this]
        {
        // update the layout
        this->centralWidget()->layout()->update();
        this->centralWidget()->layout()->activate();
        this->adjustSize();
        });
}

void MainWindow::show()
{
    QMainWindow::show();
    adjustSize();
}

Seems to work...
Unfortunately, i can't test on Windows.

SGaist

Hi,

What about adjusting your subwidget object as well ?

mpergand

@akikaede

On MacOS, adjustSize has no effect until mainwidow is shown.

void MainWindow::show()
{
    QMainWindow::show();
    adjustSize();
}

[EDIT] I end up with this:

class subwidget : public QFrame
{
    public:
subwidget(QWidget *parent): QFrame{parent}
{
    setFrameShape(QFrame::Box);
    QVBoxLayout *vlayout = new QVBoxLayout(this);
    QPushButton *btn1 = new QPushButton();
    btn2 = new QPushButton();
    vlayout->addWidget(btn1);
    vlayout->addWidget(btn2);
}

void onHide()
{
    btn2->setVisible(!btn2->isVisible());
    adjustSize();
}

    QPushButton* btn2;
};

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    QWidget *mainWidget = new QWidget(this);
    QVBoxLayout *mainlayout = new QVBoxLayout(mainWidget);
    QPushButton *hide = new QPushButton(mainWidget);
    hide->setFixedSize(200,200);
    subwidget *sub = new subwidget(mainWidget);
    mainlayout->addWidget(hide);
    mainlayout->addWidget(sub);
    mainlayout->addStretch(0);
    connect(hide, &QPushButton::clicked, sub, &subwidget::onHide);
    setCentralWidget(mainWidget);

    connect(hide, &QPushButton::clicked, this, [this]
        {
        // update the layout
        this->centralWidget()->layout()->update();
        this->centralWidget()->layout()->activate();
        this->adjustSize();
        });
}

void MainWindow::show()
{
    QMainWindow::show();
    adjustSize();
}

Seems to work...
Unfortunately, i can't test on Windows.

akikaede

@mpergand
Thank you for your solution! It works both on windows and Linux!