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1.概要
创建一个矩形，当鼠标进入这个矩形的时候，这个矩形边线变色，且鼠标变成手型
2.代码
#include <QApplication>
#include "customRectWidget.h"
/** qt 6.7版， 创建一个矩形，当鼠标进入这个矩形的时候，这个矩形边线变色，* 且鼠标变成手型，且这时候按下鼠标，鼠标可以上下拖动这个矩形，* 当鼠标松开的时候停止移动，但鼠标离开矩形的时候，矩形颜色恢复，完整代码举例；* 强调一下，鼠标进入矩形内，颜色变化，鼠标变成手型，不是鼠标进入矩形所在的控件就有上述变化。
*/
int main(int argc, char *argv[]) {QApplication app(argc, argv);CustomRectWidget widget;widget.show();return app.exec();
}
#ifndef CUSTOMRECTWIDGET_H
#define CUSTOMRECTWIDGET_H#include <QWidget>
#include <QMouseEvent>class CustomRectWidget : public QWidget {Q_OBJECTpublic:explicit CustomRectWidget(QWidget *parent = nullptr);protected:void paintEvent(QPaintEvent *event) override;void mouseMoveEvent(QMouseEvent *event) override;void mousePressEvent(QMouseEvent *event) override;void mouseReleaseEvent(QMouseEvent *event) override;void enterEvent(QEnterEvent *event) override;void leaveEvent(QEvent *event) override;void setIsChange(const QPoint &mousePos);
private:QRect rect;bool dragging;QPoint dragStartPoint;QColor hoverColor;QColor normalColor;bool isChange;bool isMouseInsideRect(const QPoint &mousePos) const;
};#endif // CUSTOMRECTWIDGET_H
#include "customRectWidget.h"
#include <QPainter>
#include <QCursor>
#include <QDebug>CustomRectWidget::CustomRectWidget(QWidget *parent): QWidget(parent), rect(50, 50, 200, 100), dragging(false), hoverColor(Qt::red), normalColor(Qt::black) {setFixedSize(300, 300);// 启用鼠标追踪，以便在鼠标没有按下时也能接收mouseMoveEventsetMouseTracking(true);
}void CustomRectWidget::setIsChange(const QPoint &mousePos){bool value = isMouseInsideRect(mousePos);if(value==isChange){return;}update();isChange = value;
}void CustomRectWidget::paintEvent(QPaintEvent *event) {Q_UNUSED(event)QPainter painter(this);painter.setRenderHint(QPainter::Antialiasing, true);QColor borderColor = normalColor;if (isMouseInsideRect(mapFromGlobal(QCursor::pos()))) {borderColor = hoverColor;}painter.setPen(QPen(borderColor, 3));painter.setBrush(Qt::white);painter.drawRect(rect);
}void CustomRectWidget::mousePressEvent(QMouseEvent *event) {setIsChange(event->pos());if (isMouseInsideRect(event->pos())) {dragging = true;dragStartPoint = event->pos();}
}void CustomRectWidget::mouseMoveEvent(QMouseEvent *event) {setIsChange(event->pos());if (dragging && isMouseInsideRect(dragStartPoint)) {int dy = event->pos().y() - dragStartPoint.y();rect.moveTop(rect.top() + dy);dragStartPoint = event->pos();update(); // Trigger repaint with new position}
}void CustomRectWidget::mouseReleaseEvent(QMouseEvent *event) {Q_UNUSED(event)dragging = false;
}void CustomRectWidget::enterEvent(QEnterEvent *event) {Q_UNUSED(event)// We manually set the cursor in the mouseMoveEvent based on the rect position
}void CustomRectWidget::leaveEvent(QEvent *event) {Q_UNUSED(event)// Cursor will be reset to default when leaving the widget
}bool CustomRectWidget::isMouseInsideRect(const QPoint &mousePos) const {bool ret = rect.contains(mousePos);if(ret) {qDebug()<<"in";}else{qDebug()<<"not in";}return ret;
}