Qt-QTreeView自定义树控件

Qt-QTreeView自定义树控件

在做中大型项目时，可能又成百上千个功能界面，而这些功能界面无非就是数据的输入与输出，那么对常用的控件进行定制是非常重要的。本人认为Qt的原生控件使用起来有以下几点问题：
1、 Qt控件为了兼容各种情况，设计得是比较抽象的，对于新员工来说理解起来比较困难，接口调用也复杂；
2、 不同的人对代码理解不同，Qt的控件用起来也是各显神通，后期维护起来非常困难；
3、 每个公司的产品有自己的外观风格，定制控件可以同一实现外观，无需开发人员自己处理。
可能刚刚看感觉比想象中的复杂一点，但是只要多看几遍就会清楚为什么Qt的控件要这样设计，项绘制部分参考了网上的代码。
主要自定义两个类，CustomTree和CustomTreeItemDelegate，类关系如下图：

核心代码：

void CustomTreeDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    painter->setRenderHint(QPainter::Antialiasing);

    //绘制背景
    QColor colorBg;
    if (option.state & QStyle::State_Selected)
    {
        colorBg = m_view->checkedBgColor();
    }
    else if (option.state & QStyle::State_MouseOver)
    {
        colorBg = m_view->hoverBgColor();
    }
    else
    {
        colorBg = m_view->bgColor();
    }
    QRect bgRect(0, option.rect.top(), m_view->width(), option.rect.height()); // 直接用option.rect，二级树左边有空白
    painter->fillRect(bgRect, colorBg);

    // 绘制checked状态的item的右侧三角形
    if (option.state & QStyle::State_Selected)
    {
        painter->setPen(Qt::NoPen);
        painter->setBrush(m_view->checkedTextColor());
        QVector<QPointF> points;
        points.append(QPointF(option.rect.right(), option.rect.top() + option.rect.height() * 0.3));
        points.append(QPointF(option.rect.right(), option.rect.top() + option.rect.height() * 0.7));
        points.append(QPointF(option.rect.right() - option.rect.height() * 0.3, option.rect.top() + option.rect.height() * 0.5));
        painter->drawPolygon(points);
    }

    //绘制+-伸缩图片
    if (m_model->itemFromIndex(index)->hasChildren())
    {
        QPixmap pix(18, 16);
        pix.fill(Qt::transparent);
        QPainter p(&pix);
        p.setRenderHint(QPainter::Antialiasing);
        int penWidth = 2;
        //根据采用的背景色判断
        QColor icoColorSelected;
        QColor icoColorNormal;
        QColor icoColorHover;
        icoColorSelected = m_view->checkedTextColor();
        icoColorNormal = m_view->textColor();
        icoColorHover = m_view->hoverTextColor();
        p.setBrush(Qt::NoBrush);
        if (option.state & QStyle::State_Selected)
        {
            p.setPen(QPen(icoColorSelected, penWidth));
        }
        else if (option.state & QStyle::State_MouseOver)
        {
            p.setPen(QPen(icoColorHover, penWidth));
        }
        else
        {
            p.setPen(QPen(icoColorNormal, penWidth));
        }
        // 绘制+-线条图片
        if (!m_view->isExpanded(index))
        {
            p.drawLine(QPointF(8, 8), QPointF(18, 8));
            p.drawLine(QPointF(12, 4), QPointF(12, 12));
        } else
        {
            p.drawLine(QPointF(8, 8), QPointF(18, 8));
        }

        QPixmap img(pix);
        QRect targetRect = option.rect;
        targetRect.setWidth(16);
        targetRect.setHeight(16);
        QPoint c = option.rect.center();
        c.setX(8 + option.rect.x());
        targetRect.moveCenter(c);
        painter->drawPixmap(targetRect, img, img.rect());
    }

    //绘制条目文字
    QColor colorText;
    if (option.state & QStyle::State_Selected)
    {
        colorText = m_view->checkedTextColor();
    }
    else if (option.state & QStyle::State_MouseOver)
    {
        colorText = m_view->hoverTextColor();
    }
    else
    {
        colorText = m_view->textColor();
    }
    painter->setPen(QPen(colorText));

    //绘制文字离左边的距离
    int margin = 25;
    QRect rect = option.rect;
    rect.setWidth(rect.width() - margin);
    rect.setX(rect.x() + margin);
    QFont normalFont("Microsoft Yahei", 9);
    painter->setFont(normalFont);
    painter->drawText(rect, Qt::AlignLeft | Qt::AlignVCenter, index.data(Qt::DisplayRole).toString());

    //绘制分隔符线条
    if (m_view->isShowLine())
    {
        painter->setPen(QPen(m_view->lineColor(), 1));
        if (!index.parent().isValid()) // 判断是否为一级item
        {
            painter->drawLine(option.rect.topLeft(), option.rect.topRight());
        }
    }

    //绘制提示信息
    QString recordInfo = m_view->infoStr(index);
    //如果不需要显示提示信息或者提示信息为空则返回
    if (recordInfo.isNull() || recordInfo.isEmpty() || !recordInfo.length())
    {
        return;
    }
    QPen decorationPen(option.state & QStyle::State_Selected ? m_view->checkedBgColor() : m_view->checkedTextColor());
    QBrush decorationBrush(option.state & QStyle::State_Selected ? m_view->checkedTextColor() : m_view->checkedBgColor());
    QFont decorationFont("Microsoft Yahei", 8);
    painter->setFont(decorationFont);
    //绘制提示信息背景
    QRect decoration = option.rect;
    decoration.setHeight(15);
    decoration.moveCenter(option.rect.center());
    decoration.setLeft(option.rect.right() - 55);
    decoration.setRight(option.rect.right() - 15);
    painter->setPen(decorationPen);
    QPainterPath path;
    path.addRoundedRect(decoration, 7, 7);
    painter->fillPath(path, decorationBrush);
    //如果是数字则将超过999的数字显示成 999+
    if (recordInfo.toInt() > 999)
    {
        recordInfo = "999+";
    }
    //如果显示的提示信息长度超过4则将多余显示成省略号..
    if (recordInfo.length() > 4) {
        recordInfo = recordInfo.mid(0, 4) + "..";
    }
    painter->drawText(decoration, Qt::AlignCenter, recordInfo);
}

void CustomTree::addItem(const QString &text, QStandardItem *parent)
{
    if (NULL == parent)
    {
        m_model->appendRow(new QStandardItem(text));
    }
    else
    {
        parent->appendRow(new QStandardItem(text));
    }
}

void CustomTree::addItem(const QString &parentText, const QString &text)
{
    QList<QStandardItem *> ls = m_model->findItems(parentText, Qt::MatchRecursive);

    if (!ls.isEmpty())
    {
        foreach (QStandardItem *item, ls)
        { // 找到的都加上
            addItem(text, item);
        }
    }
}

调用示例：

    customTree->addItem("系统参数");
    customTree->setItemInfo("系统参数", "管理员");
    customTree->addItem("轴参数");
    customTree->addItem("轴参数", "轴1");
    customTree->addItem("轴参数", "轴2");
    customTree->addItem("轴参数", "轴3");

    customTree->addItem("用户参数");
    customTree->addItem("用户参数", "公共");
    customTree->addItem("用户参数", "用户1");
    customTree->addItem("用户参数", "用户2");
    customTree->addItem("用户参数", "用户3");

    customTree->addItem("设备参数");
    customTree->addItem("设备参数", "设备1");
    customTree->addItem("设备参数", "设备2");
    customTree->addItem("设备参数", "设备3");

效果：