本文实例为大家分享了Qt实现圆圈加载进度条的具体代码，供大家参考，具体内容如下

先看效果图：

思路：画一个占270度的圆弧，然后定义一个定时器，定时旋转坐标系，实现旋转的效果。圆弧需要使用渐变色，实现颜色越来越浅的效果

关键代码：CMProcessBar1.cpp

CMProcessBar1::CMProcessBar1(QWidget *parent) : QWidget(parent), ui(new Ui::CMProcessBar1){ ui->setupUi(this); QTimer *timer = new QTimer; connect(timer,QTimer::timeout,this,updaterRotation);// 定时旋转坐标系 timer->start(3);//定时3毫秒}CMProcessBar1::~CMProcessBar1(){ delete ui;}void CMProcessBar1::updaterRotation(){ //循环360度旋转坐标系 rotation++; if(rotation == 360){ rotation = 0; } update();}void CMProcessBar1::paintEvent(QPaintEvent *event){//根据QPaintPath画出渐变色的圆弧 int width = this->width(); int height = this->height(); int side = qMin(width, height); QPainter painter(this); painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing); painter.translate(width / 2, height / 2); painter.scale(side / 200.0, side / 200.0); QConicalGradient gra(QPoint(0,0),0); gra.setColorAt(0,QColor("#3BB6FE")); gra.setColorAt(1,QColor("#FFFFFF")); QBrush brush(gra); int radis = 40; int sider = 5; QRect rect(-radis,-radis,radis*2,radis*2); QPainterPath path; path.arcTo(rect,0, 270); QPainterPath subPath; subPath.addEllipse(rect.adjusted(sider, sider, -sider, -sider)); path = path-subPath; painter.setBrush(brush);//QColor("#66CFFF") painter.setPen(Qt::NoPen); painter.rotate(rotation); painter.drawPath(path);}

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