【Qt】QStackWidget动画(2)

QStackWidget 切换动画的实现方式，通过重写 QWidget 实现

使用重写实现的切换动画使用和展示上更稳定，推荐使用当前这个。

.h 文件

#ifndef MYSTACKWIDGET_H
#define MYSTACKWIDGET_H

#include <QPropertyAnimation>

class MyStackWidget : public QWidget
{
    Q_OBJECT

public:
    MyStackWidget(QWidget *parent);
    ~MyStackWidget();

    int addWidget(QWidget *widget);             //添加控件
    int insertWidget(int index, QWidget *widget);   //插入控件
    void removeWidget(QWidget *widget);         //删除控件

    int count() const;                          //目前控件数

    void setWidgetsVisible();                   //设置控件可见

    void setCurrentWidget(QWidget *widget);     //设置当前widget显示
    void setCurrentIndex(int index);
    int currentIndex() const;                   //获取当前显示位置

    QWidget *currentWidget() const;             //获取当前显示的控件
    QWidget *widget(int index) const;
    int indexOf(QWidget *widget) const;         //获取widget所在位置

    void setDuration(int duration);             //设置动画时长

protected:
    void resizeEvent(QResizeEvent *event);

signals:
    void widgetRemoved(int);
    void currentChanged(int);

private slots:
    void onValueChanged(const QVariant &value);

private:
    QList<QWidget *> m_widgetLst;           //加入的控件链表
    QPropertyAnimation *m_moveAnimation;    //动画类
    int m_curIndex = 0;                     //当前显示位置
    int m_offset = 0;                       //需要显示的位置与当前显示的位置的偏差
    int m_lastIndex = 0;                    //最后位置
    int m_duration = 500;                   //动画显示时长，单位:ms

    void moveAnimationStart();              //启动移动动画
};

#endif // MYSTACKWIDGET_H

.cpp 文件

#include "mystackwidget.h"

#include <QDebug>
#include <QPropertyAnimation>

MyStackWidget::MyStackWidget(QWidget *parent)
    : QWidget(parent)
{
    m_offset = 0;
    m_curIndex = 0;
    m_lastIndex = 0;
    m_duration = 500;
    m_moveAnimation = new QPropertyAnimation(this, "");
    m_moveAnimation->setDuration(m_duration);
    connect(m_moveAnimation, &QPropertyAnimation::valueChanged, this, &MyStackWidget::onValueChanged);
}

MyStackWidget::~MyStackWidget()
{

}

int MyStackWidget::count() const
{
    return m_widgetLst.size();
}

int MyStackWidget::currentIndex() const
{
    return m_curIndex;
}

void MyStackWidget::setDuration(int duration)
{
    m_duration = duration;
}

int MyStackWidget::addWidget(QWidget * widget)
{
    int index = indexOf(widget);
    if (index >= 0){
        return index;
    }
    widget->setParent(this);
    m_widgetLst.append(widget);
    return count() - 1;
}

int MyStackWidget::indexOf(QWidget * widget) const
{
    return m_widgetLst.indexOf(widget);
}

int MyStackWidget::insertWidget(int index, QWidget * widget)
{
    int curindex = indexOf(widget);
    if (curindex >= 0) {
        return curindex;
    }
    widget->setParent(this);
    m_widgetLst.insert(index, widget);
    return index;
}

QWidget * MyStackWidget::currentWidget() const
{
    if (m_curIndex >= 0 && m_curIndex < count()){
        return m_widgetLst.at(m_curIndex);
    }
    return nullptr;
}

QWidget * MyStackWidget::widget(int index) const
{
    if (index >= 0 && index < count()) {
        return m_widgetLst.at(index);
    }
    return nullptr;
}

void MyStackWidget::removeWidget(QWidget * widget)
{
    int index = indexOf(widget);
    if (index >= 0) {
        m_widgetLst.removeAll(widget);
        emit widgetRemoved(index);
    }
}

void MyStackWidget::setCurrentWidget(QWidget * widget)
{
    int index = indexOf(widget);
    if (index >= 0 && m_curIndex != index) {
        setCurrentIndex(index);
    }
}

void MyStackWidget::setCurrentIndex(int index)
{
    if (index >= 0 && m_curIndex != index) {
        m_lastIndex = m_curIndex;
        m_curIndex = index;
        moveAnimationStart();
        emit currentChanged(index);
    }
}

void MyStackWidget::resizeEvent(QResizeEvent *event)
{
    QWidget::resizeEvent(event);
    int size = count();
    for (int i = 0; i < size; i++) {
        m_widgetLst.at(i)->resize(this->width(), this->height());
    }

    if (m_moveAnimation->state() == QAbstractAnimation::Running) {
        moveAnimationStart();
    }
    else {
        setWidgetsVisible();
    }
}

void MyStackWidget::onValueChanged(const QVariant &value)
{
    m_offset = value.toInt();
    m_widgetLst.at(m_curIndex)->move(m_offset, 0);
    if (m_curIndex > m_lastIndex) {
        m_widgetLst.at(m_lastIndex)->move(m_offset - this->width(), 0);
    }
    else {
        m_widgetLst.at(m_lastIndex)->move(this->width() + m_offset, 0);
    }
}

void MyStackWidget::moveAnimationStart()
{
    m_moveAnimation->stop();
    setWidgetsVisible();
    int startOffset = m_offset;
    if (m_curIndex > m_lastIndex) {
        if (startOffset == 0) startOffset = this->width();
        else startOffset = this->width() - qAbs(startOffset);
    }
    else {
        if (startOffset == 0) startOffset = -this->width();
        else startOffset = qAbs(startOffset) - this->width();
    }
    m_moveAnimation->setDuration(qAbs(startOffset) * m_duration / this->width());
    m_moveAnimation->setStartValue(startOffset);
    m_moveAnimation->setEndValue(0);
    m_moveAnimation->start();
}

void MyStackWidget::setWidgetsVisible()
{
    int size = count();
    for (int i = 0; i < size; i++) {
        if (m_lastIndex == i || m_curIndex == i)
            m_widgetLst.at(i)->setVisible(true);
        else {
            m_widgetLst.at(i)->setVisible(false);
        }
    }
}