qt - 如何重新启用qt对话框中的关闭按钮

Question

我正在使用QProgressDialog，并且在启动进度栏时禁用关闭 (x) 按钮。

progress->setWindowFlags(progress->windowFlags() & ~Qt::WindowCloseButtonHint);

在QProcess中完成操作后，在完成的插槽中，我重新启用关闭按钮，但它不起作用。相反，它会关闭进度窗口。我已经尝试了下面的两行，但效果是一样的。

progress->setWindowFlags(progress->windowFlags() | Qt::WindowCloseButtonHint);

或

progress->setWindowFlags(progress->windowFlags() | Qt::WindowCloseButtonHint | Qt::CustomizeWindowHint);

为什么它没有按应有的方式工作？

Answer 1

我发现了问题。您的对话框被隐藏了，没有办法解决这个问题。您只能再次show()它。

如doc说:

Note: This function calls setParent() when changing the flags for a window, causing the widget to be hidden. You must call show() to make the widget visible again.

来自 Qt 源代码:

void QWidget::setWindowFlags(Qt::WindowFlags flags)
{
    if (data->window_flags == flags)
        return;

    Q_D(QWidget);

    if ((data->window_flags | flags) & Qt::Window) {
        // the old type was a window and/or the new type is a window
        QPoint oldPos = pos();
        bool visible = isVisible();
        setParent(parentWidget(), flags);
        ^^^^^^^^^

        // if both types are windows or neither of them are, we restore
        // the old position
        if (!((data->window_flags ^ flags) & Qt::Window)
            && (visible || testAttribute(Qt::WA_Moved))) {
            move(oldPos);
        }
        // for backward-compatibility we change Qt::WA_QuitOnClose attribute value only when the window was recreated.
        d->adjustQuitOnCloseAttribute();
    } else {
        data->window_flags = flags;
    }
}

如 doc又说:

Note: The widget becomes invisible as part of changing its parent, even if it was previously visible. You must call show() to make the widget visible again.

例如:

MainWindow w;w.show();
w.setWindowFlags(w.windowFlags() & ~Qt::WindowCloseButtonHint);
w.setWindowFlags(w.windowFlags() | Qt::WindowCloseButtonHint);
w.show();