是否可以在QListView中添加自定义窗口小部件? [英] Is it possible to add a custom widget into a QListView?

问题描述

我有一个大的日志数据(100、1000、100000，...条记录)，我想通过以下方式对其进行可视化:

I have a large log data (100, 1000, 100000, ... records) and I want to visualize it in the following manner:

为了避免性能和内存问题，我应该使用哪个小部件(例如QListView，QListWidget)?

Which widget (e.g. QListView, QListWidget) should I use and how, in order to stay away from performance and memory problems?

推荐答案

是否可以在QListView中添加自定义窗口小部件?

Is it possible to add a custom widget into a QListView?

请阅读以下内容:

如何在Qt C ++应用程序中将包含大量小部件的可滚动列表显示为项目?

我想以上述格式显示每条日志消息

I want to show every log message in the above format

解决方案

要获得理想的结果并避免出现性能问题，即使数据日志很长，也可以使用 QListView ，带有自定义委托:

Solution

To achieve the desired result and stay away from performance issues, even with a very long data log, use a QListView with a custom delegate:

1. 创建 QStyledItemDelegate 的子类，例如

1. Create a subclass of QStyledItemDelegate, say Delegate

重新实现 QStyledItemDelegate::paint 方法来执行自定义图纸

Reimplement the QStyledItemDelegate::paint method to do the custom drawing

重新实现 QStyledItemDelegate::sizeHint 以报告正确的内容列表中项目的大小

Reimplement the QStyledItemDelegate::sizeHint to report the correct size of the items in the list

通过调用 QAbstractItemView::setItemDelegate <在视图中使用自定义委托/a>

Use the custom delegate in the view by calling QAbstractItemView::setItemDelegate

示例

我为您准备了一个工作示例，以演示如何在应用程序中实现和使用建议的解决方案.

Example

I have prepared a working example for you in order to demonstrate how the proposed solution could be implemented and used in an application.

该示例的必要部分是委托在列表视图中绘制项目的方式:

The essential part of the example is the way the delegate paints the items in the list view:

void Delegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
                     const QModelIndex &index) const
{
    QStyleOptionViewItem opt(option);
    initStyleOption(&opt, index);

    const QPalette &palette(opt.palette);
    const QRect &rect(opt.rect);
    const QRect &contentRect(rect.adjusted(m_ptr->margins.left(),
                                               m_ptr->margins.top(),
                                               -m_ptr->margins.right(),
                                               -m_ptr->margins.bottom()));
    const bool lastIndex = (index.model()->rowCount() - 1) == index.row();
    const bool hasIcon = !opt.icon.isNull();
    const int bottomEdge = rect.bottom();
    QFont f(opt.font);

    f.setPointSize(m_ptr->timestampFontPointSize(opt.font));

    painter->save();
    painter->setClipping(true);
    painter->setClipRect(rect);
    painter->setFont(opt.font);

    // Draw background
    painter->fillRect(rect, opt.state & QStyle::State_Selected ?
                          palette.highlight().color() :
                          palette.light().color());

    // Draw bottom line
    painter->setPen(lastIndex ? palette.dark().color()
                              : palette.mid().color());
    painter->drawLine(lastIndex ? rect.left() : m_ptr->margins.left(),
                      bottomEdge, rect.right(), bottomEdge);

    // Draw message icon
    if (hasIcon)
        painter->drawPixmap(contentRect.left(), contentRect.top(),
                            opt.icon.pixmap(m_ptr->iconSize));

    // Draw timestamp
    QRect timeStampRect(m_ptr->timestampBox(opt, index));

    timeStampRect.moveTo(m_ptr->margins.left() + m_ptr->iconSize.width()
                         + m_ptr->spacingHorizontal, contentRect.top());

    painter->setFont(f);
    painter->setPen(palette.text().color());
    painter->drawText(timeStampRect, Qt::TextSingleLine,
                      index.data(Qt::UserRole).toString());

    // Draw message text
    QRect messageRect(m_ptr->messageBox(opt));

    messageRect.moveTo(timeStampRect.left(), timeStampRect.bottom()
                       + m_ptr->spacingVertical);

    painter->setFont(opt.font);
    painter->setPen(palette.windowText().color());
    painter->drawText(messageRect, Qt::TextSingleLine, opt.text);

    painter->restore();
}

该示例的完整代码可在 GitHub 上找到.

The complete code of the example is available on GitHub.

如所写，给定的示例将产生以下结果:

As written, the given example produces the following result:

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