QLabel实现图片轮播效果

功能

继承QLabel控件实现了图片轮播效果
1.自定义添加图片与图片描述；
2.支持2S自动轮播
3.支持鼠标点击左下方索引按钮定位图片

效果图

这里写图片描述 这里写图片描述

代码

//示例代码
    //创建图片轮播QLabel控件
    ImageViewLabel* imagelabel = new ImageViewLabel(this);
    imagelabel->setGeometry(10, 10, 510, 208);
    //添加自定义图片和文案描述
    const QList<std::pair<QString, QString>>&& imagepairlst = { std::make_pair(":/ImageViewPager/Resources/1", QString::fromLocal8Bit("刘强东很厉害！给雨田哥发个大红包！")),\
                                                                std::make_pair(":/ImageViewPager/Resources/2", QString::fromLocal8Bit("这只是一条测试数据,快扫扫博主二维码打赏下！")),\
                                                                std::make_pair(":/ImageViewPager/Resources/3", QString::fromLocal8Bit("What!博主这么辛苦，你还不打赏下！")),
                                                                std::make_pair(":/ImageViewPager/Resources/4", QString::fromLocal8Bit("What!博主这么辛苦，你还不打赏下！")),
                                                                std::make_pair(":/ImageViewPager/Resources/5", QString::fromLocal8Bit("欢迎扫雨田哥二维码进行打赏！")), };

    imagelabel->addImage(imagepairlst);

//重写QLabel控件
#include <QPushButton>
#include <QButtonGroup>
#include <QPainter>
#include <QHBoxLayout>
#include <QPropertyAnimation> 
#include <QSequentialAnimationGroup>
#include <QParallelAnimationGroup>
#include <QDebug>
#include <QTimer>

const int btn_expand_width = 24;//按钮拉伸宽度
const int btn_shrik_width = 6;//按钮收缩宽度

ImageViewLabel::ImageViewLabel(QWidget *parent)
    : QLabel(parent)
    , m_offset(0)
    , m_curIndex(0)
    , m_preIndex(0)
    , m_blefttoright(true)
{
    setMinimumSize(120, 240);

    m_btnGroup = new QButtonGroup(this);
    connect(m_btnGroup, SIGNAL(buttonClicked(int)), SLOT(onbuttonClicked(int)));

    m_btnParalGroup = new QParallelAnimationGroup(this);
    m_imageAnimation = new QPropertyAnimation(m_btnParalGroup, "");
    m_imageAnimation->setEasingCurve(QEasingCurve::OutCirc);
    m_imageAnimation->setDuration(800);
    connect(m_imageAnimation, SIGNAL(valueChanged(const QVariant &)), this, SLOT(onImagevalueChanged(const QVariant &)));

    QSequentialAnimationGroup* sequentialGroup = new QSequentialAnimationGroup(m_btnParalGroup);
    m_btnExpAnimation = new QPropertyAnimation(sequentialGroup, "");
    m_btnExpAnimation->setEasingCurve(QEasingCurve::OutCubic);
    connect(m_btnExpAnimation, SIGNAL(valueChanged(const QVariant &)), this, SLOT(onBtnExpvalueChanged(const QVariant &)));
    m_btnExpAnimation->setDuration(400);

    m_btnShrikAnimation = new QPropertyAnimation(sequentialGroup, "");
    m_btnShrikAnimation->setEasingCurve(QEasingCurve::OutCubic);
    connect(m_btnShrikAnimation, SIGNAL(valueChanged(const QVariant &)), this, SLOT(onBtnShrikvalueChanged(const QVariant &)));
    m_btnShrikAnimation->setDuration(400);

    //按钮切换串行运行
    sequentialGroup->addAnimation(m_btnExpAnimation);
    sequentialGroup->addAnimation(m_btnShrikAnimation);

    //图片切换与按钮切换并行运行
    m_btnParalGroup->addAnimation(m_imageAnimation);
    m_btnParalGroup->addAnimation(sequentialGroup);

    initControl();
}

ImageViewLabel::~ImageViewLabel()
{

}

void ImageViewLabel::initControl()
{
    m_horizontalLayoutWidget = new QWidget(this);
    m_horizontalLayoutWidget->setObjectName(QStringLiteral("horizontalLayoutWidget"));
    m_switchBtnLayout = new QHBoxLayout(m_horizontalLayoutWidget);
    m_switchBtnLayout->setSpacing(12);
    m_switchBtnLayout->setContentsMargins(0, 0, 0, 0);

    m_imageTimer = new QTimer(this);
    m_imageTimer->setInterval(2000);
    connect(m_imageTimer, &QTimer::timeout, this, &ImageViewLabel::onImageShowTimeOut);
    m_imageTimer->start();
}

void ImageViewLabel::onImagevalueChanged(const QVariant & variant)
{
    m_offset = variant.toInt();
    update();
}

void ImageViewLabel::onBtnExpvalueChanged(const QVariant & variant)
{
    m_btnGroup->button(m_curIndex)->setFixedWidth(variant.toInt());
}

void ImageViewLabel::onBtnShrikvalueChanged(const QVariant & variant)
{
    for (int index = 0; index < m_imagepathpairlst.size(); index++){
        if (m_curIndex != index && m_btnGroup->button(index)->width() > btn_shrik_width){
            m_btnGroup->button(index)->setFixedWidth(variant.toInt());
        }
    }
}

void ImageViewLabel::onbuttonClicked(int index)
{
    if (m_curIndex == index){
        return;
    }
    if (index < 0){
        index = m_imagepathpairlst.size() - 1;
    }
    if (index >= m_imagepathpairlst.size()){
        index = 0;
    }

    m_preIndex = m_curIndex;
    m_curIndex = index;
    //图片切换
    if (m_preIndex < m_curIndex){
        //向左滑
        m_imageAnimation->setStartValue(0);
        m_imageAnimation->setEndValue(0 - width());
        m_blefttoright = false;
    }
    else{
        //向右滑
        m_imageAnimation->setStartValue(0);
        m_imageAnimation->setEndValue(width());
        m_blefttoright = true;
    }
    //按钮切换
    m_btnShrikAnimation->setStartValue(btn_expand_width);
    m_btnShrikAnimation->setEndValue(btn_shrik_width);

    m_btnExpAnimation->setStartValue(btn_shrik_width);
    m_btnExpAnimation->setEndValue(btn_expand_width);

    m_imageTimer->start(2000);
    m_btnParalGroup->start();
}

void ImageViewLabel::paintEvent(QPaintEvent *event)
{
    QLabel::paintEvent(event);
    QPainter painter(this);
    painter.setRenderHints(QPainter::SmoothPixmapTransform | QPainter::TextAntialiasing);
    QTextOption option(Qt::AlignLeft | Qt::AlignVCenter);
    painter.setPen(QColor(210, 210, 210, 200));
    QFont font = painter.font();
    font.setFamily(QString::fromLocal8Bit("微软雅黑"));
    font.setBold(true);
    font.setPixelSize(18);
    painter.setFont(font);

    if (m_blefttoright){
        painter.drawPixmap(m_offset, 0, QPixmap(m_imagepathpairlst.at(m_preIndex).first).scaled(width(), height(), Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation));
        painter.drawPixmap(m_offset - width(), 0, QPixmap(m_imagepathpairlst.at(m_curIndex).first).scaled(width(), height(), Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation));
        
        painter.drawText(QRect(m_offset + 12, height() - 52, width(), 32), m_imagepathpairlst.at(m_preIndex).second, option);
        painter.drawText(QRect(m_offset - width() + 12, height() - 52, width(), 32), m_imagepathpairlst.at(m_curIndex).second, option);
    }
    else{
        painter.drawPixmap(m_offset, 0, QPixmap(m_imagepathpairlst.at(m_preIndex).first).scaled(width(), height(), Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation));
        painter.drawPixmap(m_offset + width(), 0, QPixmap(m_imagepathpairlst.at(m_curIndex).first).scaled(width(), height(), Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation));
    
        painter.drawText(QRect(m_offset + 12, height() - 52, width(), 32), m_imagepathpairlst.at(m_preIndex).second, option);
        painter.drawText(QRect(m_offset + width() + 12, height() - 52, width(), 32), m_imagepathpairlst.at(m_curIndex).second, option);
    }
}

void ImageViewLabel::resizeEvent(QResizeEvent *event)
{
    m_horizontalLayoutWidget->setGeometry(QRect(12, height() - 18, width() -  24, 6));
    QLabel::resizeEvent(event);
}

void ImageViewLabel::addImage(const QList<std::pair<QString, QString>>& imagepathpairlst)
{
    m_imagepathpairlst = imagepathpairlst;
    for (int index = 0; index < imagepathpairlst.size(); index++)
    {
        QPushButton* btn = new QPushButton(m_horizontalLayoutWidget);
        btn->setCursor(Qt::PointingHandCursor);
        btn->setFixedSize(btn_shrik_width, btn_shrik_width);
        btn->setStyleSheet("QPushButton{border-image:url(:/ImageViewPager/Resources/point.png);border-width:0 3px;}");
        m_btnGroup->addButton(btn, index);
        m_switchBtnLayout->addWidget(btn);
    }
    m_switchBtnLayout->addStretch();
    m_btnGroup->button(m_curIndex)->setFixedWidth(btn_expand_width);
    update();
}

void ImageViewLabel::onImageShowTimeOut()
{
    onbuttonClicked(m_curIndex + 1);
}

工程文件

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在这里插入图片描述

结尾

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