Qt6子窗口全屏显示的实现示例

QWidget::showFullScreen(); // 此方法只对顶级窗口有效，对子窗口无效

QWidget::showNormal(); // 此方法也只对顶级窗口有效，对子窗口无效

QWidget::showMinimized();

QWidget::showMaximized();

QWidget::setWindowFlags(Qt::WindowFlags);

    enum WindowType {
        Widget = 0x00000000,
        Window = 0x00000001,
        Dialog = 0x00000002 | Window,
        Sheet = 0x00000004 | Window,
        Drawer = Sheet | Dialog,
        Popup = 0x00000008 | Window,
        Tool = Popup | Dialog,
        ToolTip = Popup | Sheet,
        SplashScreen = ToolTip | Dialog,
        Desktop = 0x00000010 | Window,
        SubWindow = 0x00000012,
        ForeignWindow = 0x00000020 | Window,
        CoverWindow = 0x00000040 | Window,
        ...
    };

void MainWindow::on_pushButtonHideFullScreen_clicked() {
    if (this->isFullScreen()) {
        this->showNormal();
        ui->widgetControl->show();
        ui->statusbar->show();
    } else {
        this->showFullScreen();
        ui->widgetControl->hide();
        ui->statusbar->hide();
    }
}

void MainWindow::keyPressEvent(QKeyEvent *event) {
    if (this->isFullScreen() && event->key() == Qt::Key_Escape) {
        qDebug() << "ESC";
        this->showNormal();
        ui->widgetControl->show();
        ui->statusbar->show();
    }
}

    // 子窗口全屏
    QWidget *fsWidget_ = nullptr;
    Qt::WindowFlags fsFlags_;

    void enableChildFullScreen();
    void disableChildFullScreen();

void MainWindow::enableChildFullScreen() {
    fsWidget_ = ui->openGLWidget;
    fsFlags_ = fsWidget_->windowFlags();

    fsWidget_->setWindowFlags(Qt::Window | Qt::WindowStaysOnTopHint |
                              Qt::FramelessWindowHint);
    fsWidget_->setFocus();
    fsWidget_->showFullScreen();
    fsWidget_->installEventFilter(this);
}

void MainWindow::disableChildFullScreen() {
    fsWidget_->setWindowFlags(fsFlags_);
    fsWidget_->showNormal();
    fsWidget_->removeEventFilter(this);
    fsWidget_ = nullptr;
}

void MainWindow::on_pushButtonChildFullScreen_clicked() {
    if (!fsWidget_) {
        qDebug() << "enable full screen";
        enableChildFullScreen();
    } else {
        qDebug() << "disable full screen";
        disableChildFullScreen();
    }
}

bool MainWindow::eventFilter(QObject *watched, QEvent *event) {
    if (fsWidget_ != nullptr && watched == fsWidget_ &&
        event->type() == QEvent::KeyPress) {
        qDebug() << "ESC";
        QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
        if (keyEvent->key() == Qt::Key_Escape) {
            disableChildFullScreen();

            return true; // 事件已处理，不传递给其他对象
        }
    }

    return QMainWindow::eventFilter(watched, event); // 将事件传递给基类处理
}