Qt模仿IOS滑动按钮效果

#ifndef SWITCHBUTTON_H
#define SWITCHBUTTON_H
 
#include <QWidget>
#include<QTimer>
 
class switchButton : public QWidget
{
  Q_OBJECT
public:
  explicit switchButton(QWidget *parent = 0);
  void writeSwitchButtonState(bool ison);
  bool readSwitchButtonState();
private:
  bool ison=false;
  float currentValue;
  float widthSize,heightSize;
  QTimer *timer;
  void paintEvent(QPaintEvent *event);//绘制事件
  void mousePressEvent(QMouseEvent *event);//点击事件
signals:
 
public slots:
private slots:
  void begainAnimation();
};
 
#endif // SWITCHBUTTON_H

#include "switchbutton.h"
#include <QPaintEvent>
#include<QPainter>
#include<QRectF>
#include<QRect>
/**
 * @brief switchButton::switchButton
 * @param parent
 * 创建的这个switchbutton只是提供固定的大小，展示实现的过程。
 */
 
switchButton::switchButton(QWidget *parent) : QWidget(parent)
{
  setMaximumSize(200,130);
  setMinimumSize(200,130);
  widthSize=(float)width();
  heightSize=(float)height();
  timer=new QTimer(this);
  timer->setInterval(50);
  if(ison){
    currentValue=widthSize-0.95*heightSize;
  }else{
    currentValue=0.05*heightSize;
  }
  connect(timer,SIGNAL(timeout()),this,SLOT(begainAnimation()));
 
}
void switchButton::paintEvent(QPaintEvent *event){
  Q_UNUSED(event)
  QPainter painter(this);
  painter.setRenderHint(QPainter::SmoothPixmapTransform);
  painter.setRenderHint(QPainter::Antialiasing);
  painter.setPen(Qt::NoPen);
  if(ison){
    painter.save();
    painter.setBrush(Qt::green);
    QRectF greenRect=QRectF(0,0,widthSize,heightSize);
    painter.drawRoundedRect(greenRect,0.5*heightSize,0.5*heightSize);
    painter.restore();
    painter.save();
    painter.setBrush(Qt::white);
    painter.drawEllipse(currentValue,0.05*heightSize,0.9*heightSize,0.9*heightSize);
    painter.restore();
  }else{
    painter.save();
    QColor grayColor(199,199,199);
    painter.setBrush(grayColor);
    QRectF roundRect=QRectF(0,0,widthSize,heightSize);
    painter.drawRoundedRect(roundRect,0.5*heightSize,0.5*heightSize);
    painter.restore();
    painter.save();
    painter.setBrush(Qt::red);
    QRectF redRect=QRectF(heightSize*0.05,heightSize*0.05,widthSize-heightSize*0.1,heightSize*0.9);
    painter.drawRoundedRect(redRect,0.45*heightSize,0.45*heightSize);
    painter.restore();
    painter.save();
    painter.setBrush(Qt::white);
    painter.drawEllipse(currentValue,0.05*heightSize,0.9*heightSize,0.9*heightSize);
    painter.restore();
  }
}
void switchButton::mousePressEvent(QMouseEvent *event){
  Q_UNUSED(event)
  ison=!ison;
  timer->start(10);
  this->update();
}
void switchButton::begainAnimation(){
  int i=0.05*heightSize;
  int n=widthSize-0.95*heightSize;
  if(ison){
    currentValue+=1;
    if(currentValue>n-i){
      timer->stop();
    }
  }else{
    currentValue-=1;
    if(currentValue<i){
      timer->stop();
    }
  }
  update();
}
 
void switchButton::writeSwitchButtonState(bool ison)
{
  this->ison=ison;
  this->update();
}
bool switchButton::readSwitchButtonState()
{
  return this->ison;
}