用qt4和c++实现QScrollArea实现鼠标滑动

可以使用Qt的事件过滤器来实现鼠标滑动。 首先，将QScrollArea设置为可滚动： ```cpp QScrollArea *scrollArea = new QScrollArea(this); scrollArea->setWidgetResizable(true); ``` 然后，在构造函数中安装事件过滤器： ```cpp scrollArea->viewport()->installEventFilter(this); ``` 接下来，重写事件过滤器函数： ```cpp bool YourClassName::eventFilter(QObject *obj, QEvent *event) { if (obj == scrollArea->viewport() && event->type() == QEvent::Wheel) { // 鼠标滚轮事件 QWheelEvent *wheelEvent = static_cast<QWheelEvent*>(event); int delta = wheelEvent->delta(); int scrollBarValue = scrollArea->verticalScrollBar()->value(); scrollArea->verticalScrollBar()->setValue(scrollBarValue - delta); return true; } return false; } ``` 在这个事件过滤器函数中，我们捕获QScrollArea的视口（viewport）的鼠标滚轮事件，并获取滚动的距离delta，计算出当前滚动条的值，然后设置滚动条的值为当前值减去delta。 最后，在类的头文件中声明事件过滤器函数： ```cpp protected: bool eventFilter(QObject *obj, QEvent *event) override; ``` 完整示例代码： ```cpp #include <QtWidgets> class Widget : public QWidget { public: Widget(QWidget *parent = nullptr) : QWidget(parent) { QVBoxLayout *layout = new QVBoxLayout(this); QScrollArea *scrollArea = new QScrollArea(this); scrollArea->setWidgetResizable(true); QWidget *widget = new QWidget(scrollArea); QVBoxLayout *widgetLayout = new QVBoxLayout(widget); for (int i = 0; i < 100; ++i) { QLabel *label = new QLabel(QString("Label %1").arg(i + 1), widget); widgetLayout->addWidget(label); } widget->setLayout(widgetLayout); scrollArea->setWidget(widget); layout->addWidget(scrollArea); scrollArea->viewport()->installEventFilter(this); } protected: bool eventFilter(QObject *obj, QEvent *event) override { QScrollArea *scrollArea = qobject_cast<QScrollArea*>(obj); if (scrollArea && event->type() == QEvent::Wheel) { QWheelEvent *wheelEvent = static_cast<QWheelEvent*>(event); int delta = wheelEvent->delta(); int scrollBarValue = scrollArea->verticalScrollBar()->value(); scrollArea->verticalScrollBar()->setValue(scrollBarValue - delta); return true; } return false; } }; int main(int argc, char *argv[]) { QApplication a(argc, argv); Widget w; w.show(); return a.exec(); } ```