无法更改button的颜色和buttontext的颜色，使用qstyle自己画pushbutton，在风格选项中设置的palette解决思路

void CommentWidget::paintEvent(QPaintEvent *e)
{
    QPainter painter(this);
    painter.save();
    painter.setRenderHint(QPainter::Antialiasing);//开启边缘反锯齿
    QSize size=this->size();
    qDebug()<<size;

QPalette palette=QPalette(Qt::white);

    //画刷的活动颜色组
    palette.setBrush(QPalette::Window,Qt::lightGray);//窗口背景颜色
    palette.setBrush(QPalette::WindowText,Qt::black);//窗口前景颜色

    palette.setBrush(QPalette::Base,Qt::white);
    palette.setBrush(QPalette::AlternateBase,Qt::lightGray);

    palette.setBrush(QPalette::Text,Qt::black);
    palette.setBrush(QPalette::Button,Qt::white);//按钮颜色
    palette.setBrush(QPalette::ButtonText,Qt::red);//按钮文字颜色

//画底部按钮
    QStyleOptionButton opt;
    opt.initFrom(this);
opt.text = "Reply";
    opt.rect=QRect(size.width()-180,size.height()-70+10,80,50);
    opt.state=QStyle::State_Enabled;
    opt.fontMetrics=QApplication::fontMetrics();
    opt.palette=palette;

this->style()->drawControl(QStyle::CE_PushButton,&opt,&painter,this);

painter.restore();

}