QT实现banner轮播图,要求按Z序大小堆叠,中间为选中项并最大有阴影, 展示5张图片, 3秒滚动一次, 不使用QML

以下是一个不使用QML的简单实现方案：

#include <QApplication>
#include <QLabel>
#include <QHBoxLayout>
#include <QTimer>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    //创建容器widget和布局
    QWidget *container = new QWidget;
    QHBoxLayout *layout = new QHBoxLayout;
    container->setLayout(layout);
    container->setStyleSheet("background-color: black");

    //创建5个label用于展示图片
    QLabel *label1 = new QLabel(container);
    QLabel *label2 = new QLabel(container);
    QLabel *label3 = new QLabel(container);
    QLabel *label4 = new QLabel(container);
    QLabel *label5 = new QLabel(container);
    label1->setPixmap(QPixmap(":/banner1.jpg"));
    label2->setPixmap(QPixmap(":/banner2.jpg"));
    label3->setPixmap(QPixmap(":/banner3.jpg"));
    label4->setPixmap(QPixmap(":/banner4.jpg"));
    label5->setPixmap(QPixmap(":/banner5.jpg"));

    //将label添加到布局中
    layout->addWidget(label1);
    layout->addWidget(label2);
    layout->addWidget(label3);
    layout->addWidget(label4);
    layout->addWidget(label5);

    //设置label的对齐方式和阴影效果
    for (auto label : container->findChildren<QLabel*>()) {
        label->setAlignment(Qt::AlignCenter);
        label->setScaledContents(true);
        label->setGraphicsEffect(new QGraphicsDropShadowEffect);
    }

    //设置初始选中项和Z值
    int currentIndex = 0;
    label1->raise();
    label1->setGraphicsEffect(nullptr);
    label2->setGraphicsEffect(nullptr);
    label3->setGraphicsEffect(nullptr);
    label4->setGraphicsEffect(nullptr);
    label5->setGraphicsEffect(nullptr);

    //定时器控制自动滚动
    QTimer timer;
    QObject::connect(&timer, &QTimer::timeout, [&]() {
        currentIndex = (currentIndex + 1) % 5;
        switch (currentIndex) {
        case 0:
            label1->raise();
            label1->setGraphicsEffect(nullptr);
            label2->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label3->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label4->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label5->setGraphicsEffect(new QGraphicsDropShadowEffect);
            break;
        case 1:
            label2->raise();
            label1->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label2->setGraphicsEffect(nullptr);
            label3->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label4->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label5->setGraphicsEffect(new QGraphicsDropShadowEffect);
            break;
        case 2:
            label3->raise();
            label1->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label2->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label3->setGraphicsEffect(nullptr);
            label4->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label5->setGraphicsEffect(new QGraphicsDropShadowEffect);
            break;
        case 3:
            label4->raise();
            label1->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label2->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label3->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label4->setGraphicsEffect(nullptr);
            label5->setGraphicsEffect(new QGraphicsDropShadowEffect);
            break;
        case 4:
            label5->raise();
            label1->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label2->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label3->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label4->setGraphicsEffect(new QGraphicsDropShadowEffect);
            label5->setGraphicsEffect(nullptr);
            break;
        }
    });
    timer.start(3000);

    //显示窗口
    container->show();
    return app.exec();
}

这个实现方案使用了QWidget作为容器，QHBoxLayout作为布局。每个图片使用一个QLabel来展示，通过设置QGraphicsEffect来实现阴影效果。定时器控制了自动滚动，通过修改选中项和Z值来切换图片和阴影效果。