Qt添加自定义控件

由于在自带的控件中没有发现滚动选择时间的控件，所以参考网上别人写的控件做了一点修改。

先看效果：

上代码:

TimeScroll.h

QT_BEGIN_NAMESPACE
namespace Ui { class TimeScroll; }
QT_END_NAMESPACE

class TimeScroll : public QWidget
{
    Q_OBJECT
    Q_PROPERTY(int deviation READ readDeviation WRITE setDeviation )

public:
    TimeScroll(QWidget *parent = nullptr);
    ~TimeScroll();

    void setRange(double min, double max);
    void setCurrentValue(double value);
        //获取当前值
    double readValue();

protected:
    void mousePressEvent(QMouseEvent *);

    void mouseMoveEvent(QMouseEvent *);

    void mouseReleaseEvent(QMouseEvent *);

    void wheelEvent(QWheelEvent *);

    void paintEvent(QPaintEvent *);
    //描绘数字
    void paintNum(QPainter &painter, double num, int deviation,bool isMiddle= false);
    //使选中的数字回到屏幕中间
    void homing();
    //鼠标移动偏移量，默认为0
    int readDeviation();
    //设置偏移量
    void setDeviation(int n);

signals:

    void currentValueChanged(double value);

    void deviationChange(double deviation);


private:
    double m_minRange;      //最小值
    double m_maxRange;      //最大值
    double m_currentValue;  //当前选中的值
    bool isDragging;        //鼠标是否按下
    int m_deviation;        //偏移量,记录鼠标按下后移动的垂直距离
    int m_mouseSrcPos;
    int m_numSize;
    QPropertyAnimation *homingAni;
    const double interval;  //间隔大小
    const int devide;       //分隔数量

    Ui::TimeScroll *ui;
};

TimeScroll.cpp

TimeScroll::TimeScroll(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::TimeScroll),
    m_minRange(0),      //最小值默认为0
    m_maxRange(59),    //最大值默认100
    m_currentValue(0), //当前值默认50
    isDragging(false),
    m_deviation(0),     //默认偏移量为0
    m_numSize(12),
    interval(1),      //间隔默认0.5
    devide(7)           //默认分成7格
{

    ui->setupUi(this);

    homingAni = new QPropertyAnimation(this, "deviation");
    homingAni->setDuration(300);
    homingAni->setEasingCurve(QEasingCurve::OutQuad);
}

TimeScroll::~TimeScroll()
{
    delete ui;
}
/*
 * 设置范围
 * double min 最小值
 * double max 最大值
*/
void TimeScroll::setRange(double min, double max)
{
    m_minRange = min;
    m_maxRange = max;
    if (m_currentValue < min)
    {
        m_currentValue = min;
    }
    if (m_currentValue > max)
    {
        m_currentValue = max;
    }
    repaint();
}
/*
 * 设置当前值
 *  double value 传入的当前值
 */
void TimeScroll::setCurrentValue(double value) {
    if(value < m_minRange){
        m_currentValue = m_minRange;
    }
    if(value > m_maxRange){
        m_currentValue = m_maxRange;
    }
    repaint();
}
//获取当前值
double TimeScroll::readValue()
{
    if(m_currentValue < m_minRange){
        return m_maxRange - (m_minRange-m_currentValue) + 1;
    }
    if(m_currentValue > m_maxRange){
        return m_minRange + (m_currentValue - m_maxRange) - 1;
    }
    return m_currentValue;
}

void TimeScroll::mousePressEvent(QMouseEvent *e)
{
    qDebug()<<"mouse pressed on vertical scroll";

    homingAni->stop();
    isDragging = true;
    m_mouseSrcPos = e->pos().y();
    QWidget::mousePressEvent(e);
}

void TimeScroll::mouseMoveEvent(QMouseEvent *e)
{
    if (isDragging)
    {
//        if ((m_currentValue == m_minRange && e->pos().y() >= m_mouseSrcPos) ||
//                ( m_currentValue == m_maxRange && e->pos().y() <= m_mouseSrcPos ))
//        {
//            return;
//        }
//        if ((m_currentValue < m_minRange - (devide * interval)&& e->pos().y() >= m_mouseSrcPos)){
//                m_currentValue = (int)qAbs(m_currentValue)%(int)(m_maxRange + 1);
//        }
//        if(m_currentValue > m_maxRange + (devide * interval) && e->pos().y() <= m_mouseSrcPos){
//                m_currentValue = (int)m_currentValue%(int)(m_maxRange + 1);
//        }
        m_deviation = e->pos().y() - m_mouseSrcPos;
        //若移动速度过快，则进行限制
        if (m_deviation > (height() - 1) / devide)
        {
            m_deviation = (height() - 1) / devide;
        }
        else if (m_deviation < -(height() - 1) / devide)
        {
            m_deviation = -( height() - 1) / devide;
        }
        qInfo()<<m_deviation;

        emit deviationChange((double)m_deviation / ((height() - 1) / devide));
        repaint();
    }
}

void TimeScroll::mouseReleaseEvent(QMouseEvent *)
{
    if (isDragging)
    {
        isDragging = false;
        homing();
    }
}

void TimeScroll::wheelEvent(QWheelEvent *e)
{
    if (e->delta() > 0)
    {
        m_deviation = (this->height() - 1) / devide;
    }
    else
    {
        m_deviation = -(this->height() - 1) / devide;
    }
    homing();
    repaint();
}

void TimeScroll::paintEvent(QPaintEvent *e)
{
    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing, true);
    int Height = height() - 1;

    if ( m_deviation >= Height / devide && m_currentValue > (m_minRange - devide * interval ))
    {
        m_mouseSrcPos += Height / devide;
        m_deviation -= Height / devide;
        m_currentValue -= interval;
    }

    if ( m_deviation <= -Height / devide && m_currentValue < (m_maxRange + devide * interval))
    {
        m_mouseSrcPos -= Height / devide;
        m_deviation += Height / devide;
        m_currentValue += interval;
    }
    qInfo()<< "paint:"<<m_deviation;
    //middle number
    if(m_currentValue < (m_minRange + devide/2)){
        // 中间值
        if(m_currentValue >= m_minRange){
            paintNum(painter,m_currentValue,m_deviation,true);
            for(int i = 1; i <= devide/2; ++i){
                paintNum(painter,m_currentValue + i,m_deviation + Height / devide*i);
                if(m_currentValue - i - m_minRange< 0){
                    paintNum(painter,m_maxRange + (m_currentValue  -  i) + 1 - m_minRange,m_deviation - Height / devide*i);
                }else{
                    paintNum(painter,m_currentValue - i,m_deviation - Height / devide*i);
                }
            }
        }else{
            paintNum(painter,m_maxRange - (m_minRange - m_currentValue) + 1,m_deviation,true);
            for(int i = 1; i <= devide/2; ++i){
                paintNum(painter,m_maxRange - (m_minRange - m_currentValue) + 1 - i,m_deviation - Height / devide*i);
                if(( m_currentValue - m_minRange) + 1 + i > 0){
                    paintNum(painter,m_minRange + ( m_currentValue - m_minRange)  + i,m_deviation + Height / devide*i);
                }else{
                    paintNum(painter,m_maxRange - (m_minRange - m_currentValue) + 1 + i,m_deviation + Height / devide *i);
                }
            }
            if(m_currentValue == m_minRange - devide/2 -1){
                m_currentValue = m_maxRange - devide/2;
            }
        }

    }else if(m_currentValue > m_maxRange - devide/2){
        if(m_currentValue <= m_maxRange){
            paintNum(painter,m_currentValue,m_deviation,true);
            for(int i = 1; i <= devide/2; ++i){
                paintNum(painter,m_currentValue - i,m_deviation - Height / devide *i);
                if(m_currentValue + i > m_maxRange){
                    paintNum(painter,     m_minRange + m_currentValue -m_maxRange +i -1,m_deviation + Height / devide *i);
                }else{
                    paintNum(painter,m_currentValue +i,m_deviation + Height / devide*i);
                }
            }
        }else{
            paintNum(painter,m_minRange + (m_currentValue - m_maxRange) - 1,m_deviation,true);
            for(int i = 1; i <= devide/2; ++i){
                paintNum(painter,m_minRange + (m_currentValue - m_maxRange) + i - 1,m_deviation + Height / devide *i);
                if( (m_currentValue - m_maxRange) - 1- i < 0){
                    paintNum(painter,  m_currentValue - i,m_deviation - Height / devide *i);
                }else{
                    paintNum(painter,m_minRange + (m_currentValue - m_maxRange) -i - 1,m_deviation - Height / devide * i);
                }
            }
            if(m_currentValue == m_maxRange + devide/2 + 1){
                m_currentValue = m_minRange + devide/2;
            }
        }
    }else{
        paintNum(painter,m_currentValue,m_deviation,true);
        for(int i = 1; i <= devide/2; ++i){
            paintNum(painter,m_currentValue- interval *i,m_deviation - Height / devide *i);
            paintNum(painter,m_currentValue+ interval *i,m_deviation + Height / devide *i);
        }
    }

}
/*
 * 根据偏移量描绘数字
 * double num 需要显示的数字
 * int deviation 数字相对中间的偏移量
*/
void TimeScroll::paintNum(QPainter &painter, double num, int deviation,bool isMiddle)
{
    int Width = width() - 1;
    int Height = height() - 1;
    int size = (Height - qAbs(deviation)) / m_numSize; //偏移量越大，数字越小
    int transparency = 255 - 255 * qAbs(deviation) / Height;
    int height = Height / devide;
    int y = Height / 2 + deviation - height / 2;

    QFont font;
    font.setPixelSize(size);
    painter.setFont(font);
    painter.setPen(QColor(255, 2,2,transparency));

    if ( y >= 0 && y + height < Height)
    {
        // 中间值画框
        if(isMiddle) {
            painter.drawRect(0, y, Width, height);
        }
        painter.drawText(QRectF(0, y, Width-20, height),
                         Qt::AlignCenter,
                         QString::number(num, 'f', 1));
    }
}

/*
 * 使选中的数字回到屏幕中间
*/
void TimeScroll::homing()
{
    if ( m_deviation > height() / 10)
    {
        homingAni->setStartValue( ( height() - 1 ) / 8 - m_deviation);
        homingAni->setEndValue(0);
        m_currentValue -= interval;
    }
    else if ( m_deviation > -height() / 10 )
    {
        homingAni->setStartValue(m_deviation);
        homingAni->setEndValue(0);
    }
    else if ( m_deviation < -height() / 10 )
    {
        homingAni->setStartValue(-(height() - 1) / 8 - m_deviation);
        homingAni->setEndValue(0);
        m_currentValue += interval;
    }

    emit currentValueChanged(m_currentValue);
    homingAni->start();
}

int TimeScroll::readDeviation()
{
    return m_deviation;
}

void TimeScroll::setDeviation(int n)
{
    m_deviation = n;
    repaint();
}