#ifndef SMOOTHSTACKEDWIDGET_H
#define SMOOTHSTACKEDWIDGET_H#include <QObject>
#include <QWidget>
#include <QStackedWidget>
#include <QAbstractScrollArea>
#include <QPixmap>
#include <QPropertyAnimation>class SmoothStackedWidget : public QStackedWidget
{Q_OBJECT#define SMOOTH_MAX_MS   900                   //平滑滑动时的最大延迟时间
#define SMOOTH_EDGE_MOVE_RATIO   0.14         //边缘移动系数,范围0~1,越低越慢typedef enum tagScrollMouseDragInfo {MOUSE_RELEASE = 0,                       //鼠标离开MOUSE_PRESS = 1,                         //按下MOUSE_PRESS_MOVE = 2,                    //按下移动MOUSE_RELEASE_MOVE = 3                   //鼠标离开并滑动}Scroll_Mouse_Drag_INFO_E;typedef enum tagSmoothAnimationSwitchInfo {SWITCH_PRE = -1,                      //切换上一页SWITCH_NONE = 0,                      //不切换SWITCH_NEXT = 1,                      //切换下一页}AnimationSwitch_Drag_INFO_E;Scroll_Mouse_Drag_INFO_E m_dragFlag = MOUSE_RELEASE;AnimationSwitch_Drag_INFO_E m_switchFlag = SWITCH_NONE;QWidget *m_parent;QWidget m_smoothWidget;int m_smoothCurrentIndex=-1;QPropertyAnimation *animation;float m_smoothMovePos;bool eventFilter(QObject *obj, QEvent *evt) override;void paintEvent(QPaintEvent *event) override;void resizeEvent(QResizeEvent *event) override;void SmoothLoadPixmap(bool isSmoothUpdate = false);void SmoothStartMove();void SmoothMove(int offset);void SmoothAnimationStart(int startPos, int endPos, int durationMs);void SmoothAnimationInit();public:explicit SmoothStackedWidget(QWidget *parent = nullptr);int addWidget(QAbstractScrollArea *w);int addWidget(QWidget *w);void setCurrentIndex(int index);void removeWidget(QWidget *w);void IconUpdate();      //刷新页数标签void UpdateSmooth();signals:protected slots:void OnSmoothAnimationFinished();};#endif // SMOOTHSTACKEDWIDGET_H

bool SmoothStackedWidget::eventFilter(QObject *obj, QEvent *evt)
{QMouseEvent *mouse =  dynamic_cast<QMouseEvent *>(evt);QWidget *w =  dynamic_cast<QWidget *>(obj);static int pressPoint_x   = 0;          //按下的坐标static int dragPoint_x    = -1;         //拖动时的坐标static qint64 pressMSec ;if(mouse && w && animation->state() == QAbstractAnimation::Stopped){if( mouse->type() ==QEvent::MouseButtonPress)    //首次按下{pressMSec = QDateTime::currentDateTime().toMSecsSinceEpoch();     //记录按下的时间dragPoint_x  = mouse->pos().x();               //当前坐标pressPoint_x = dragPoint_x;                    //按下的位置m_dragFlag = MOUSE_PRESS;}else if(mouse->type() == QEvent::MouseButtonRelease &&m_dragFlag == MOUSE_PRESS)               //未移动{m_dragFlag = MOUSE_RELEASE;}else if(mouse->type() == QEvent::MouseMove &&m_dragFlag == MOUSE_PRESS)               //初次滑动,判断移动阀值,避免误操作{if(qAbs(dragPoint_x - mouse->pos().x()) > 3)     //判断移动阀值,避免误操作{dragPoint_x = mouse->pos().x();SmoothStartMove();m_dragFlag = MOUSE_PRESS_MOVE;}}else if(mouse->type() == QEvent::MouseMove &&m_dragFlag== MOUSE_PRESS_MOVE )             //正在滑动{int offset = ( mouse->pos().x() - dragPoint_x);SmoothMove(offset);dragPoint_x = mouse->pos().x();}else if(mouse->type() == QEvent::MouseButtonRelease &&m_dragFlag == MOUSE_PRESS_MOVE)               //滑动结束,启动平滑滑动{int durationMs= QDateTime::currentDateTime().toMSecsSinceEpoch()-pressMSec;SmoothAnimationStart(pressPoint_x,mouse->pos().x(),durationMs);m_dragFlag = MOUSE_RELEASE;}}return QWidget::eventFilter(obj,evt);
}

void  SmoothStackedWidget::SmoothAnimationStart(int startPos, int endPos, int durationMs)
{int pixelPerSecond=qAbs(endPos - startPos)*1000/durationMs;       //计算每秒像素点m_switchFlag = SWITCH_NONE;int moveX = qAbs(m_smoothWidget.x());float temp = width()*0.5;int animationEndX;//慢速滑动(速度过慢||时间过长),则根据当前滑到哪里,就跳到哪里if(pixelPerSecond<300 || durationMs > 1000) {if(moveX < (temp)) {        //[0,width/2] = 上一页if(currentIndex()==0) {animationEndX = -width();} else {animationEndX = 0;m_switchFlag = SWITCH_PRE;}} else if(moveX < (temp*3)) {    //[width/2,width*3/2] = 当前一页animationEndX = -width();} else {if(currentIndex()==(count()-1)) {   //[width*3/2,width*2] = 下一页animationEndX = -width();} else {animationEndX = -width()*2;m_switchFlag = SWITCH_NEXT;}}} else {　　　　// 否则就是快速滑动if(startPos < endPos) { //向右滑动if(currentIndex()==0) {animationEndX = -width();} else {animationEndX = 0;m_switchFlag = SWITCH_PRE;}} else {         //向左滑动if(currentIndex()==(count()-1)) {animationEndX = -width();} else {animationEndX = -width()*2;m_switchFlag = SWITCH_NEXT;}}}//根据每秒滑动像素点,来计算滑动时长.int animationDuration = durationMs;float xOffsetRatio = qAbs(animationEndX - m_smoothWidget.x()) / (static_cast<float>(width())); //计算滑动占整屏比例if(animationDuration > (SMOOTH_MAX_MS * xOffsetRatio)) //滑动时间过大,则重置animationDuration = SMOOTH_MAX_MS * xOffsetRatio;animation->setDuration(animationDuration);animation->setStartValue(m_smoothWidget.geometry());animation->setEndValue(QRect(animationEndX, m_smoothWidget.y(), m_smoothWidget.width(), m_smoothWidget.height()));animation->start();
}