QT里没有找到数字滚动的控件，想实现数字滚动的效果只好自己实现。参考了http://blog.csdn.net/big_c_god/article/details/52452631
可以在代码中设定显示范围和刻度。为了美观还可以加上背景，这里没加。代码里有注释，方便理解。废话不说了，贴代码.
头文件
#ifndef VERTICALSCROLL_H #define VERTICALSCROLL_H #include <QWidget> #include <QPropertyAnimation> #include <QPainter> namespace Ui { class VerticalScroll; } class VerticalScroll : public QWidget { Q_OBJECT Q_PROPERTY(int deviation READ readDeviation WRITE setDeviation ) public: explicit VerticalScroll(QWidget *parent = 0); ~VerticalScroll(); //设置范围 void setRange(double min, double max); //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); //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: Ui::VerticalScroll *ui; 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 }; #endif // VERTICALSCROLL_H源文件
#include "verticalscroll.h" #include "ui_verticalscroll.h" #include <QMouseEvent> #include <QDebug> VerticalScroll::VerticalScroll(QWidget *parent) : QWidget(parent), ui(new Ui::VerticalScroll), m_minRange(0), //最小值默认为0 m_maxRange(100), //最大值默认100 m_currentValue(50), //当前值默认50 isDragging(false), m_deviation(0), //默认偏移量为0 m_numSize(12), interval(0.5), //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); } VerticalScroll::~VerticalScroll() { delete ui; } /* * 设置范围 * double min 最小值 * double max 最大值 */ void VerticalScroll::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(); } //获取当前值 double VerticalScroll::readValue() { return m_currentValue; } void VerticalScroll::mousePressEvent(QMouseEvent *e) { qDebug()<<"mouse pressed on vertical scroll"; homingAni->stop(); isDragging = true; m_mouseSrcPos = e->pos().y(); QWidget::mousePressEvent(e); } void VerticalScroll::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; } 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; } emit deviationChange((double)m_deviation / ((height() - 1) / devide)); repaint(); } } void VerticalScroll::mouseReleaseEvent(QMouseEvent *) { if (isDragging) { isDragging = false; homing(); } } void VerticalScroll::wheelEvent(QWheelEvent *e) { if (e->delta() > 0) { m_deviation = (this->height() - 1) / devide; } else { m_deviation = -(this->height() - 1) / devide; } homing(); repaint(); } void VerticalScroll::paintEvent(QPaintEvent *) { QPainter painter(this); painter.setRenderHint(QPainter::Antialiasing, true); int Height = height() - 1; if ( m_deviation >= Height / devide && m_currentValue > m_minRange ) { m_mouseSrcPos += Height / devide; m_deviation -= Height / devide; m_currentValue -= interval; } if ( m_deviation <= -Height / devide && m_currentValue < m_maxRange ) { m_mouseSrcPos -= Height / devide; m_deviation += Height / devide; m_currentValue += interval; } //middle number paintNum(painter, m_currentValue, m_deviation); //两侧数字1 if (m_currentValue != m_minRange) { paintNum(painter, m_currentValue - interval, m_deviation - Height / devide); } if (m_currentValue != m_maxRange) { paintNum(painter, m_currentValue + interval, m_deviation + Height / devide); } for (int i=2; i <= devide/2; ++i) { if (m_currentValue - interval * i >= m_minRange) { paintNum(painter, m_currentValue - interval * i, m_deviation - Height / devide * i); } if (m_currentValue + interval * i <= m_maxRange) { 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 VerticalScroll::paintNum(QPainter &painter, double num, int deviation) { 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) { 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 VerticalScroll::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 VerticalScroll::readDeviation() { return m_deviation; } void VerticalScroll::setDeviation(int n) { m_deviation = n; repaint(); }效果如下图：
通过滚动鼠标，数字会随着上下移动。如果觉得有帮助，欢迎留言或点赞。
