• QT中窗口自绘制效果展示

    项目中需要使用QT进行窗口自绘，前期先做一下技术探索，参考相关资料代码熟悉流程。本着代码是最好的老师原则，在此记录一下。

    目录

    1.运行效果

    2.代码结构

    3.具体代码

    1.运行效果

    2.代码结构

    3.具体代码

    myspeed.pro

    1. QT       += core gui
    2.  
    3. greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
    4.  
    5. CONFIG += c++17
    6.  
    7. # You can make your code fail to compile if it uses deprecated APIs.
    8. # In order to do so, uncomment the following line.
    9. #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
    10.  
    11. SOURCES += \
    12.     drawdialog.cpp \
    13.     main.cpp \
    14.     meter1.cpp \
    15.     meter2.cpp
    16.  
    17. HEADERS += \
    18.     drawdialog.h \
    19.     meter1.h \
    20.     meter2.h
    21.  
    22. # Default rules for deployment.
    23. qnx: target.path = /tmp/$${TARGET}/bin
    24. else: unix:!android: target.path = /opt/$${TARGET}/bin
    25. !isEmpty(target.path): INSTALLS += target

    drawdialog.h

    1. #include 
    2.  
    3. class DrawDialog : public QDialog
    4. {
    5.      Q_OBJECT
    6.  
    7. public:
    8.      explicit DrawDialog(QWidget *parent = 0);
    9.      void mousePressEvent(QMouseEvent *event);
    10.      void mouseMoveEvent(QMouseEvent *event);
    11.      void paintEvent(QPaintEvent *event) ;
    12.      void keyPressEvent( QKeyEvent * event );
    13. private:
    14.      QPoint m_CurrentPos;
    15. };

    meter1.h

    1. #ifndef METER1_H
    2. #define METER1_H
    3.  
    4. #include 
    5. #include 
    6.  
    7. // 仪表盘开发参考博客
    8. // https://blog.csdn.net/yyz_1987/article/details/126958420#comments_29151980
    9. class MyMeter1 : public QWidget
    10. {
    11.     Q_OBJECT
    12.  
    13. public:
    14.     MyMeter1(QWidget *parent = 0);
    15.     ~MyMeter1();
    16.  
    17.     void setValue(double val);
    18.  
    19. protected:
    20.     void paintEvent(QPaintEvent *);
    21.  
    22.     void drawCrown(QPainter *painter);
    23.     void drawBackground(QPainter *painter);
    24.     void drawScale(QPainter *painter);
    25.     void drawScaleNum(QPainter *painter);
    26.     void drawTitle(QPainter *painter);
    27.     void drawIndicator(QPainter *painter);
    28.     void drawNumericValue(QPainter *painter);
    29.  
    30. protected:
    31.     void mouseMoveEvent(QMouseEvent *event);
    32.     void mousePressEvent(QMouseEvent *event);
    33.     void mouseReleaseEvent(QMouseEvent *event);
    34.  
    35. private:
    36.     QPoint mousePoint;
    37.     bool mouse_press;
    38.  
    39. private:
    40.     QColor m_background;
    41.     QColor m_foreground;
    42.  
    43.  
    44.     int m_maxValue;
    45.     int m_minValue;
    46.     int m_startAngle;
    47.     int m_endAngle;
    48.  
    49.     int m_scaleMajor;
    50.     int m_scaleMinor;
    51.     double m_value;
    52.     int m_precision;
    53.     QTimer *m_updateTimer;
    54.     QString m_units;
    55.     QString m_title;
    56.  
    57. public Q_SLOTS:
    58.     void UpdateAngle();
    59.  
    60. private:
    61.  
    62. };
    63.  
    64. #endif // METER1_H

    meter2.h

    1. #ifndef METER2_H
    2. #define METER2_H
    3.  
    4. #include 
    5.  
    6. class MyMeter2 : public QWidget
    7. {
    8.     Q_OBJECT
    9.  
    10. public:
    11.     MyMeter2(QWidget *parent = nullptr);
    12.     ~MyMeter2();
    13.  
    14.     void paintEvent(QPaintEvent *event);
    15.     void timerEvent(QTimerEvent *e);
    16.  
    17. private:
    18.     void drawFrame(QPainter *painter);
    19.     void drawScale(QPainter *painter);
    20.     void drawScaleNum(QPainter *painter);
    21.  
    22.     void drawPointer(QPainter *painter);
    23.     void drawSpeed(QPainter *painter);
    24.  
    25.     void drawUnit(QPainter *painter);
    26.  
    27.  
    28.     int speed;
    29.     int time_id;
    30.     int status;
    31.     qreal m_angle;
    32.     QColor m_foreground;
    33.  
    34.     int m_maxValue;
    35.     int m_minValue;
    36.     int m_startAngle;
    37.     int m_endAngle;
    38.  
    39.     int m_scaleMajor;
    40.     int m_scaleMinor;
    41.     double m_value;
    42.     int m_precision;
    43.     //QTimer *m_updateTimer;
    44.     QString m_units;
    45.     QString m_title;
    46.  
    47. };
    48. #endif // METER2_H

    drawdialog.cpp

    1. #include "drawdialog.h"
    2. #include 
    3. #include 
    4. #include 
    5.  
    6. DrawDialog::DrawDialog(QWidget *parent) : QDialog(parent)
    7.  {
    8.      //让程序无边框
    9.      setWindowFlags( Qt::FramelessWindowHint );
    10.      //让程序背景透明
    11.      setAttribute(Qt::WA_TranslucentBackground, true);
    12. }
    13.  
    14. void DrawDialog::mousePressEvent(QMouseEvent *event)
    15. {
    16.      //当鼠标左键按下时，记录当前位置
    17.      if(event->button() == Qt::LeftButton)
    18.      {
    19.          m_CurrentPos = event->globalPos() - frameGeometry().topLeft();
    20.          event->accept();
    21.      }
    22.       QDialog::mousePressEvent(event);
    23. }
    24.  
    25. void DrawDialog::mouseMoveEvent(QMouseEvent *event)
    26. {
    27.      //支持窗体移动
    28.      if (event->buttons() & Qt::LeftButton)
    29.       {
    30.          move(event->globalPos() - m_CurrentPos);
    31.          event->accept();
    32.      }
    33.  
    34.      QDialog::mouseMoveEvent(event);
    35.     }
    36.  
    37.   //绘制图形
    38.  void DrawDialog::paintEvent(QPaintEvent *event)
    39.  {
    40.       QPainter painter(this);
    41.       //反走样
    42.       painter.setRenderHint(QPainter::Antialiasing,true);
    43.  
    44.      painter.setPen( QPen(Qt::green, 2) );
    45.      painter.setBrush( Qt::blue );
    46.      QRect rect(10,10,200,260);
    47.      //绘制一个椭圆
    48.      painter.drawEllipse(rect);
    49.  }
    50.  
    51. void DrawDialog::keyPressEvent( QKeyEvent * event )
    52. {
    53.       //按下esc键时，关闭
    54.       if(event->key() == Qt::Key_Escape)
    55.       {
    56.           close();
    57.       }
    58. }

    meter1.cpp

    1. #include "meter1.h"
    2.  
    3. #include 
    4.  
    5. // 构造函数
    6. MyMeter1::MyMeter1(QWidget *parent){
    7.  
    8.     m_background = Qt::black;
    9.     m_foreground = Qt::white;
    10.  
    11.     m_startAngle = 60;
    12.     m_endAngle = 60;
    13.     m_scaleMajor = 10;
    14.     m_minValue = 0;
    15.     m_maxValue = 100;
    16.     m_scaleMajor = 10;//分度
    17.     m_scaleMinor = 10;
    18.     m_units = "L/min";
    19.     m_title = "仪表盘";
    20.     m_precision = 0;
    21.     m_value = 0;
    22.     mouse_press = false;
    23.  
    24.     setWindowFlags(Qt::FramelessWindowHint);//无窗体
    25.     setAttribute(Qt::WA_TranslucentBackground);//背景透明
    26.     resize(500, 500);
    27.  
    28. }
    29.  
    30. MyMeter1::~MyMeter1()
    31. {
    32.  
    33. }
    34.  
    35. void MyMeter1::setValue(double val)
    36. {
    37.     m_value = val;
    38. }
    39. //绘制表冠
    40. void MyMeter1::drawCrown(QPainter *painter)
    41. {
    42.     painter->save();
    43.     int radius = 100;
    44.     QLinearGradient lg1(0, -radius, 0, radius);
    45.  
    46.     lg1.setColorAt(0, Qt::white); //设置渐变的颜色和路径比例
    47.     lg1.setColorAt(1, Qt::gray); //只是粗略的颜色，具体的可以参考RGB颜色查询对照表
    48.  
    49.     painter->setBrush(lg1); // 创建QBrush对象,把这个渐变对象传递进去：
    50.     painter->setPen(Qt::NoPen); //边框线无色
    51.     painter->drawEllipse(-radius, -radius, radius << 1, radius << 1);
    52.     painter->setBrush(m_background = Qt::black);
    53.     painter->drawEllipse(-92, -92, 184, 184);
    54.     painter->restore();
    55. }
    56.  
    57.  //绘制刻度数字
    58. void MyMeter1::drawScaleNum(QPainter *painter)
    59. {
    60.     painter->save();
    61.     painter->setPen(m_foreground);
    62.     //m_startAngle是起始角度，m_endAngle是结束角度，m_scaleMajor在一个量程中分成的刻度数
    63.     double startRad = ( 270-m_startAngle) * (3.14 / 180);
    64.     double deltaRad = (360 - m_startAngle - m_endAngle) * (3.14 / 180) / m_scaleMajor;
    65.     double sina,cosa;
    66.     int x, y;
    67.     QFontMetricsF fm(this->font());
    68.     double w, h, tmpVal;
    69.     QString str;
    70.  
    71.     for (int i = 0; i <= m_scaleMajor; i++)
    72.     {
    73.         sina = sin(startRad - i * deltaRad);
    74.         cosa = cos(startRad - i * deltaRad);
    75.  
    76.        tmpVal = 1.0 * i *((m_maxValue - m_minValue) / m_scaleMajor) + m_minValue;
    77.        // tmpVal = 50;
    78.         str = QString( "%1" ).arg(tmpVal);  //%1作为占位符   arg()函数比起 sprintf()来是类型安全的
    79.         w = fm.size(Qt::TextSingleLine,str).width();
    80.         h = fm.size(Qt::TextSingleLine,str).height();
    81.         x = 82 * cosa - w / 2;
    82.         y = -82 * sina + h / 4;
    83.         painter->drawText(x, y, str); //函数的前两个参数是显示的坐标位置，后一个是显示的内容，是字符类型""
    84.  
    85.     }
    86.     painter->restore();
    87. }
    88.  
    89. // 绘制刻度线
    90. void MyMeter1::drawScale(QPainter *painter) //绘制刻度线
    91. {
    92.     painter->save();
    93.     painter->rotate(m_startAngle);
    94.     int steps = (m_scaleMajor * m_scaleMinor); //相乘后的值是分的份数
    95.     double angleStep = (360.0 - m_startAngle - m_endAngle) / steps; //每一个份数的角度
    96.  
    97.     // painter->setPen(m_foreground); //m_foreground是颜色的设置
    98.     // QPen pen = painter->pen(); //第一种方法
    99.     QPen pen ;
    100.     pen.setColor(Qt::green); //推荐使用第二种方式
    101.     for (int i = 0; i <= steps; i++)
    102.     {
    103.     if (i % m_scaleMinor == 0)//整数刻度显示加粗
    104.     {
    105.     pen.setWidth(1); //设置线宽
    106.     painter->setPen(pen); //使用面向对象的思想，把画笔关联上画家。通过画家画出来
    107.  
    108.       painter->drawLine(0, 62, 0, 72); //两个参数应该是两个坐标值
    109.        }
    110.        else
    111.        {
    112.            pen.setWidth(0);
    113.            painter->setPen(pen);
    114.            painter->drawLine(0, 67, 0, 72);
    115.        }
    116.        painter->rotate(angleStep);
    117.     }
    118.     painter->restore();
    119. }
    120.  
    121. void MyMeter1::drawTitle(QPainter *painter)
    122. {
    123.     painter->save();
    124.     painter->setPen(m_foreground);
    125.     //painter->setBrush(m_foreground);
    126.     QString str(m_title); //显示仪表的功能
    127.     QFontMetricsF fm(this->font());
    128.     double w = fm.size(Qt::TextSingleLine,str).width();
    129.     painter->drawText(-w / 2, -30, str);
    130.     painter->restore();
    131. }
    132.  
    133. // 显示的单位，与数值
    134. void MyMeter1::drawNumericValue(QPainter *painter)
    135. {
    136.     QString str = QString("%1 %2").arg(m_value, 0, 'f', m_precision).arg(m_units);
    137.     QFontMetricsF fm(font());
    138.     double w = fm.size(Qt::TextSingleLine,str).width();
    139.     painter->setPen(m_foreground);
    140.     painter->drawText(-w / 2, 42, str);
    141. }
    142.  
    143. void MyMeter1::UpdateAngle()
    144. {
    145.     update();
    146. }
    147.  
    148. // 绘制表针，和中心点
    149. void MyMeter1::drawIndicator(QPainter *painter)
    150. {
    151.     painter->save();
    152.     QPolygon pts;
    153.     pts.setPoints(3, -2, 0, 2, 0, 0, 60);	/* (-2,0)/(2,0)/(0,60) *///第一个参数是 ，坐标的个数。后边的是坐标
    154.  
    155.     painter->rotate(m_startAngle);
    156.     double degRotate = (360.0 - m_startAngle - m_endAngle) / (m_maxValue - m_minValue)*(m_value - m_minValue);
    157.  
    158.     //画指针
    159.     painter->rotate(degRotate);  //顺时针旋转坐标系统
    160.     QRadialGradient haloGradient(0, 0, 60, 0, 0);  //辐射渐变
    161.     haloGradient.setColorAt(0, QColor(60, 60, 60));
    162.     haloGradient.setColorAt(1, QColor(160, 160, 160)); //灰
    163.     painter->setPen(Qt::white); //定义线条文本颜色  设置线条的颜色
    164.     painter->setBrush(haloGradient);//刷子定义形状如何填满 填充后的颜色
    165.     painter->drawConvexPolygon(pts); //这是个重载函数，绘制多边形。
    166.     painter->restore();
    167.  
    168.     //画中心点
    169.     QColor niceBlue(150, 150, 200);
    170.     QConicalGradient coneGradient(0, 0, -90.0);  //角度渐变
    171.     coneGradient.setColorAt(0.0, Qt::darkGray);
    172.     coneGradient.setColorAt(0.2, niceBlue);
    173.     coneGradient.setColorAt(0.5, Qt::white);
    174.     coneGradient.setColorAt(1.0, Qt::darkGray);
    175.     painter->setPen(Qt::NoPen);  //没有线，填满没有边界
    176.     painter->setBrush(coneGradient);
    177.     painter->drawEllipse(-5, -5, 10, 10);
    178. }
    179.  
    180. // 重绘函数
    181. void MyMeter1 ::paintEvent(QPaintEvent *)
    182. {
    183.  
    184.     int width=this->width();
    185.     int height=this->height();
    186.  
    187.     QPainter painter(this);//一个类中的this表示一个指向该类自己的指针
    188.  
    189.     painter.setRenderHint(QPainter::Antialiasing);  /* 使用反锯齿(如果可用) */
    190.     painter.translate(width/2, height/2);   /* 坐标变换为窗体中心 */
    191.     int side = qMin(width, height);
    192.     painter.scale(side / 200.0, side / 200.0);      /* 比例缩放 */
    193.  
    194.    drawCrown(&painter);                                 /* 画表盘边框 */
    195.    drawScaleNum(&painter);                          /* 画刻度数值值 */
    196.    drawScale(&painter);                                 /* 画刻度线 */
    197.    drawTitle(&painter);                                 /* 画单位 */
    198.    drawNumericValue(&painter);                      /* 画数字显示 */
    199.    drawIndicator(&painter);                             /* 画表针 */
    200.  
    201. }
    202.  
    203. void MyMeter1::mousePressEvent(QMouseEvent *event)
    204.  {
    205.  
    206.       if( (event->button() == Qt::LeftButton) ){
    207.           mouse_press = true;
    208.          mousePoint = event->globalPos() - this->pos();
    209.  //        event->accept();
    210.       }
    211.     else if(event->button() == Qt::RightButton){
    212.        //如果是右键
    213.         this->close();
    214.  
    215.      }
    216. }
    217.  
    218. void MyMeter1::mouseMoveEvent(QMouseEvent *event)
    219. {
    220.  
    221.  
    222. //    if(event->buttons() == Qt::LeftButton){  //如果这里写这行代码，拖动会有点问题
    223.      if(mouse_press){
    224.          move(event->globalPos() - mousePoint);
    225. //        event->accept();
    226.      }
    227. }
    228.  
    229. void MyMeter1::mouseReleaseEvent(QMouseEvent *event)
    230. {
    231.     mouse_press = false;
    232. }

    meter2.cpp

    1. #include "meter2.h"
    2.  
    3. #include 
    4. #include 
    5. #include 
    6. #include 
    7. #include 
    8. #include 
    9.  
    10. #include 
    11.  
    12. MyMeter2::MyMeter2(QWidget *parent)
    13.     : QWidget(parent)
    14. {
    15.     //resize(800, 480);
    16.     //setWindowTitle("test");
    17.  
    18.     m_foreground = Qt::red;//Qt::black;
    19.  
    20.     speed = 0;
    21.     status = 0;
    22.  
    23.     m_startAngle = 45;
    24.     m_endAngle = 45;
    25.  
    26.     m_minValue = 0;
    27.     m_maxValue = 100;
    28.  
    29.     m_scaleMajor = 10;//分度
    30.     m_scaleMinor = 10;
    31.     m_units = "KM/H";
    32.     m_title = "My Speed";
    33.     m_precision = 0;
    34.     m_value = 0;
    35.  
    36.     m_angle = (qreal)270/(m_maxValue-1);
    37.     //setWindowFlags(Qt::FramelessWindowHint);//无窗体
    38.     //setAttribute(Qt::WA_TranslucentBackground);//背景透明
    39.     time_id = this->startTimer(50);
    40. }
    41.  
    42. MyMeter2::~MyMeter2()
    43. {
    44. }
    45.  
    46. void MyMeter2::paintEvent(QPaintEvent *event)
    47. {
    48.     int width=this->width();
    49.     int height=this->height();
    50.  
    51.  
    52.     QPainter painter(this);
    53.  
    54.     painter.translate(width/2, height/2);
    55.  
    56.     int side = qMin(width, height);
    57.     painter.scale(side / 200.0, side / 200.0);      /* 比例缩放 */
    58.  
    59.     drawFrame(&painter);
    60.  
    61.     drawScale(&painter);                                 /* 画刻度线 */
    62.  
    63.     drawScaleNum(&painter);                          /* 画刻度数值值 */
    64.     drawUnit(&painter);
    65.     drawPointer(&painter);
    66.  
    67.     drawSpeed(&painter);
    68. }
    69.  
    70. void MyMeter2::drawFrame(QPainter *painter)
    71. {
    72.     painter->save();
    73.     // 半径100
    74.     int radius = 100;
    75.  
    76.     painter->setBrush(QBrush(QColor(0, 255, 0, 255), Qt::SolidPattern));
    77.     painter->drawArc(-radius, -radius, radius<<1, radius<<1, -135*16, -270*16);
    78.  
    79.     painter->restore();
    80.  
    81. }
    82.  
    83. // 绘制刻度线
    84. void MyMeter2::drawScale(QPainter *painter)
    85. {
    86.  
    87.     painter->save();
    88.     painter->rotate(m_startAngle);
    89.     int steps = (m_scaleMajor * m_scaleMinor); //相乘后的值是分的份数
    90.     double angleStep = (360.0 - m_startAngle - m_endAngle) / steps; //每一个份数的角度
    91.  
    92.     // painter->setPen(m_foreground); //m_foreground是颜色的设置
    93.     // QPen pen = painter->pen(); //第一种方法
    94.     QPen pen ;
    95.     pen.setColor(m_foreground); //推荐使用第二种方式
    96.     for (int i = 0; i <= steps; i++)
    97.     {
    98.         if (i % m_scaleMinor == 0)//整数刻度显示加粗
    99.         {
    100.             pen.setWidth(1); //设置线宽
    101.             painter->setPen(pen); //使用面向对象的思想，把画笔关联上画家。通过画家画出来
    102.  
    103.             painter->drawLine(0, 90, 0, 100); //两个参数应该是两个坐标值
    104.         }
    105.         else
    106.         {
    107.            pen.setWidth(0);
    108.            painter->setPen(pen);
    109.            painter->drawLine(0, 95, 0, 100);
    110.         }
    111.        painter->rotate(angleStep);
    112.     }
    113.     painter->restore();
    114. }
    115. // 绘制刻度
    116. void MyMeter2::drawScaleNum(QPainter *painter)
    117. {
    118.     painter->save();
    119.     painter->setPen(m_foreground);
    120.     //m_startAngle是起始角度，m_endAngle是结束角度，m_scaleMajor在一个量程中分成的刻度数
    121.     double startRad = ( 270-m_startAngle) * (3.14 / 180);
    122.     double deltaRad = (360 - m_startAngle - m_endAngle) * (3.14 / 180) / m_scaleMajor;
    123.     double sina,cosa;
    124.     int x, y;
    125.     QFontMetricsF fm(this->font());
    126.     double w, h, tmpVal;
    127.     QString str;
    128.  
    129.     for (int i = 0; i <= m_scaleMajor; i++)
    130.     {
    131.         sina = sin(startRad - i * deltaRad);
    132.         cosa = cos(startRad - i * deltaRad);
    133.  
    134.        tmpVal = 1.0 * i *((m_maxValue - m_minValue) / m_scaleMajor) + m_minValue;
    135.        // tmpVal = 50;
    136.         str = QString( "%1" ).arg(tmpVal);  //%1作为占位符   arg()函数比起 sprintf()来是类型安全的
    137.         w = fm.size(Qt::TextSingleLine,str).width();
    138.         h = fm.size(Qt::TextSingleLine,str).height();
    139.         x = 82 * cosa - w / 2;
    140.         y = -82 * sina + h / 4;
    141.         painter->drawText(x, y, str); //函数的前两个参数是显示的坐标位置，后一个是显示的内容，是字符类型""
    142.  
    143.     }
    144.     painter->restore();
    145. }
    146.  
    147. void MyMeter2::drawPointer(QPainter *painter)
    148. {
    149.     int radius = 100;
    150.     QPoint point[4] = {
    151.         QPoint(0, 10),
    152.         QPoint(-10, 0),
    153.         QPoint(0, -80),
    154.         QPoint(10, 0),
    155.     };
    156.  
    157.     painter->save();
    158.  
    159.     QLinearGradient linear;
    160.     linear.setStart(-radius, -radius);
    161.     linear.setFinalStop(radius<<1, radius<<1);
    162.     linear.setColorAt(0, QColor(0, 255, 255, 0));
    163.     linear.setColorAt(1, QColor(0, 255, 255, 255));
    164.     painter->setPen(Qt::NoPen);
    165.     painter->setBrush(linear);
    166.     painter->drawPie(-radius, -radius, radius<<1, radius<<1, 225 * 16, -(m_angle * this->speed) * 16);
    167.  
    168.     painter->restore();
    169.  
    170.     painter->save();
    171.  
    172.     painter->setBrush(QBrush(QColor(0, 0, 0, 255), Qt::SolidPattern));
    173.     painter->rotate(-135 + this->speed * m_angle);
    174.     painter->drawPolygon(point, 4);
    175.  
    176.     painter->restore();
    177. }
    178.  
    179. void MyMeter2::drawSpeed(QPainter *painter)
    180. {
    181.     painter->save();
    182.  
    183.     painter->setPen(QColor("#0"));
    184.     //  绘制速度
    185.     QFont font("Times", 10, QFont::Bold);
    186.     font.setBold(true);
    187.     font.setPixelSize(46);
    188.     painter->setFont(font);
    189.     painter->drawText(-60, 0, 120, 92, Qt::AlignCenter, QString::number(speed));
    190.     painter->restore();
    191. }
    192.  
    193. void MyMeter2::drawUnit(QPainter *painter)
    194. {
    195.     QString str = QString("%1").arg(m_units);
    196.     QFontMetricsF fm(font());
    197.     double w = fm.size(Qt::TextSingleLine,str).width();
    198.     painter->setPen(m_foreground);
    199.     painter->drawText(-w / 2, 82, str);
    200. }
    201.  
    202. void MyMeter2::timerEvent(QTimerEvent *e)
    203. {
    204.     int timerId = e->timerId();
    205.  
    206.     if(this->time_id == timerId) {
    207.         if(this->status == 0) {
    208.             this->speed += 1;
    209.             if(this->speed >= m_maxValue)
    210.                 this->status = 1;
    211.         }else {
    212.             this->speed -= 1;
    213.             if(this->speed <= 0)
    214.                 this->status = 0;
    215.  
    216.         }
    217.  
    218.         this->update();
    219.     }
    220. }
    221.

    main.cpp

    1. #include "mainwindow.h"
    2. #include "meter1.h"
    3. #include "meter2.h"
    4. #include "drawdialog.h"
    5. #include 
    6.  
    7. int main(int argc, char *argv[])
    8. {
    9.     QApplication a(argc, argv);
    10.  
    11.     MyMeter1 w1;
    12.     w1.setValue(33.12);
    13.     w1.show();
    14.  
    15.     MyMeter2 w2;
    16.     w2.show();
    17.  
    18.     DrawDialog w3;
    19.     w3.show();
    20.  
    21.     return a.exec();
    22. }

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  • 原文地址：https://blog.csdn.net/hsy12342611/article/details/133967375