Qlabel实现高亮显示搜索关键字封装类

1.1 封装高亮显示检索关键字控件

需要对搜索的关键字进行高亮显示，而QLabel只能通过setstytlesheet函数去设置一种字体颜色，无法实现一行文字多种颜色，像这种名字中把搜索关键字高亮显示的需求，无法用简单的QLabel实现，可以通过QTextDocument加载html脚本，来实现检索关键词高亮显示，有多个关键词时，都会高亮显示；封装成一个类，只需要设置进去显示文字和高亮文字就可以了。实现方法如下所示：

（1）头文件

#ifndef COLLORLABEL_H
#define COLLORLABEL_H

#include <QObject>
#include <QLabel>
#include <QTextDocument>
class CollorLabel : public QLabel
{
    Q_OBJECT

public:
    CollorLabel();
    ~CollorLabel();
    void paintEvent(QPaintEvent *event);
    void SetName(QString strName) { m_strName = strName; };
    
    void SetfilterHover(QString filterHover) { m_filterHover = filterHover; };
private:
    QString m_strName="";
    QString m_filterHover="";
    QTextDocument* m_LabelName;
};

#endif // COLLORLABEL_H

（2）源文件

#include "CollorLabel.h"
#include <QPainter>
#include <QColor>
#include <QBrush>
#include <QRect>
#include <QPoint>
CollorLabel::CollorLabel()
{
    m_LabelName=new QTextDocument(this);
    m_LabelName->setUndoRedoEnabled(false);
    m_LabelName->setDocumentMargin(0);
    //背景色设置为透明，这样鼠标放入就有hover的颜色
    setStyleSheet(QLatin1String("QLabel\n"
        "{\n"
        "    font-family: Microsoft YaHei UI;\n"
        "    font-size: 16px;\n"
        "    color: rgba(255,255,255,0.70);\n"
        "    letter-spacing: 0;\n"
        "    line-height: 24px;\n"
        "    background: rgba(255,255,255,0);\n"
        "    background:transparent;\n"
        "}\n"
        "QToolTip\n"
        "{\n"
        "    font-size:14px;\n"
        "    width:1024;\n"
        "    height:40;\n"
        "    font-family: Microsoft YaHei UI;\n"
        "}"));

    setAttribute(Qt::WA_TranslucentBackground);
}

CollorLabel::~CollorLabel()
{

}

void CollorLabel::paintEvent(QPaintEvent *event)
{
    QPainter ffpainter(this);
    QPainter* painter = &ffpainter;
    painter->save();

    //QBrush background_brush= QColor(255, 255, 255, 0);    // 透明色
    //painter->fillRect(this->rect(), background_brush);
    QColor text_color=QColor(255,255,255,0.7);          // 文本颜色
    QColor filter_color= QColor(250, 50, 57, 255);      // 高亮颜色
                                                          // 高亮文本
    QString filter_text = m_filterHover;  // 文字与过滤文字首先获取出来
    QString text = m_strName;
    painter->setFont(this->font());

    QFontMetrics font_metrics(this->font());
    int text_width = this->width();

    m_LabelName->setDefaultFont(this->font());

    // 右部显示省略号
    QFontMetrics font_width(this->font());
    text = font_width.elidedText(text, Qt::ElideRight, text_width);

    // 然后将匹配项加上font-color标签，若非空的话
    if (!filter_text.isEmpty())
    {
        int last_index = text.lastIndexOf(filter_text, -1, Qt::CaseInsensitive);
        while (last_index != -1)
        {
            text.insert(last_index + filter_text.length(), "</font>");
            text.insert(last_index, QString("<font color=%1>").arg(filter_color.name()));
            last_index = text.lastIndexOf(filter_text, last_index, Qt::CaseInsensitive);
        }
    }

    // 在文档中设置字体，并设置文字
    m_LabelName->setHtml(QString("<font color=%1>%2</font>").arg(text_color.name()).arg(text));
    int y = this->height();//居中显示高度
    y = y / 2 - 10;
    if (y<0)
    {
        y = 0;
    }
    QRect text_rect = QRect(this->x(), y, text_width, 20);  // 文字高度为20，所以文字上下空白为6px
    painter->translate(QPoint(text_rect.x(), text_rect.y() + (text_rect.height() - font_metrics.height()) / 2));
    m_LabelName->drawContents(painter, text_rect.translated(-text_rect.x(), -text_rect.y()));

    painter->restore();
    

    
    
}