Qt编写提示进度条的实现示例

#ifndef PROGRESSTIP_H
#define PROGRESSTIP_H

/**
 * 提示进度条控件 作者:feiyangqingyun(QQ:517216493) 2019-10-05
 * 1:可设置最小值/最大值/范围值/当前值
 * 2:可设置是否百分比显示
 * 3:可设置边距,流出空隙防止提示信息跑到外面
 * 4:可设置进度的颜色,可以是渐变画刷
 * 5:可设置背景颜色/文字颜色/提示背景
 * 6:可设置圆角角度
 * 7:如果设置了进度画刷则提示背景也采用该画刷
 */

#include <QWidget>

#ifdef quc
#if (QT_VERSION < QT_VERSION_CHECK(5,7,0))
#include <QtDesigner/QDesignerExportWidget>
#else
#include <QtUiPlugin/QDesignerExportWidget>
#endif

class QDESIGNER_WIDGET_EXPORT ProgressTip : public QWidget
#else
class ProgressTip : public QWidget
#endif

{
    Q_OBJECT
    Q_PROPERTY(double minValue READ getMinValue WRITE setMinValue)
    Q_PROPERTY(double maxValue READ getMaxValue WRITE setMaxValue)
    Q_PROPERTY(double value READ getValue WRITE setValue)

    Q_PROPERTY(bool percent READ getPercent WRITE setPercent)
    Q_PROPERTY(int padding READ getPadding WRITE setPadding)
    Q_PROPERTY(int radius READ getRadius WRITE setRadius)

    Q_PROPERTY(QBrush valueBrush READ getValueBrush WRITE setValueBrush)
    Q_PROPERTY(QColor valueColor READ getValueColor WRITE setValueColor)
    Q_PROPERTY(QColor bgColor READ getBgColor WRITE setBgColor)
    Q_PROPERTY(QColor tipColor READ getTipColor WRITE setTipColor)
    Q_PROPERTY(QColor textColor READ getTextColor WRITE setTextColor)

public:
    explicit ProgressTip(QWidget *parent = 0);

protected:
    void paintEvent(QPaintEvent *);    
    void drawBg(QPainter *painter);
    void drawTip(QPainter *painter);
    void drawValue(QPainter *painter);

private:
    double minValue;            //最小值
    double maxValue;            //最大值
    double value;               //目标值

    bool percent;               //百分比显示
    int padding;                //边距
    int radius;                 //圆角角度

    QBrush valueBrush;          //进度画刷
    QColor valueColor;          //进度颜色
    QColor bgColor;             //背景颜色
    QColor tipColor;            //提示背景颜色
    QColor textColor;           //文字颜色

public:
    double getMinValue()        const;
    double getMaxValue()        const;
    double getValue()           const;

    bool getPercent()           const;
    int getPadding()            const;
    int getRadius()             const;

    QBrush getValueBrush()      const;
    QColor getValueColor()      const;
    QColor getBgColor()         const;
    QColor getTipColor()        const;
    QColor getTextColor()       const;

    QSize sizeHint()            const;
    QSize minimumSizeHint()     const;

public Q_SLOTS:
    //设置范围值
    void setRange(double minValue, double maxValue);
    void setRange(int minValue, int maxValue);

    //设置最大最小值
    void setMinValue(double minValue);
    void setMaxValue(double maxValue);

    //设置目标值
    void setValue(double value);
    void setValue(int value);

    //设置百分比显示
    void setPercent(bool percent);
    //设置边距
    void setPadding(int padding);
    //设置圆角角度
    void setRadius(int radius);

    //设置进度画刷+进度颜色+背景颜色+提示背景+文字颜色
    void setValueBrush(const QBrush &valueBrush);
    void setValueColor(const QColor &valueColor);
    void setBgColor(const QColor &bgColor);
    void setTipColor(const QColor &tipColor);
    void setTextColor(const QColor &textColor);

Q_SIGNALS:
    void valueChanged(double value);
};

#endif // PROGRESSPLAY_H

void ProgressTip::paintEvent(QPaintEvent *)
{
    //绘制准备工作,启用反锯齿,平移坐标轴中心,等比例缩放
    QPainter painter(this);
    painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing);

    //绘制背景
    drawBg(&painter);
    //绘制上部分提示信息
    drawTip(&painter);
    //绘制进度
    drawValue(&painter);
}

void ProgressTip::drawBg(QPainter *painter)
{
    painter->save();
    painter->setPen(Qt::NoPen);
    painter->setBrush(bgColor);

    QRect rect(padding, (height() / 3) * 2, width() - padding * 2, height() / 3);
    painter->drawRoundedRect(rect, radius, radius);

    painter->restore();
}

void ProgressTip::drawTip(QPainter *painter)
{
    painter->save();
    painter->setPen(Qt::NoPen);
    painter->setBrush(valueBrush == Qt::NoBrush ? tipColor : valueBrush);

    //计算当前值对应的百分比
    double step = value / (maxValue - minValue);
    int progress = (width() - padding * 2) * step;

    //绘制上部分提示信息背景
    QRect rect(progress, 0, padding * 2, (double)height() / 2.1);
    painter->drawRoundedRect(rect, 2, 2);

    //绘制倒三角
    int centerX = rect.center().x();
    int initY = rect.height();
    int offset = 5;
    QPolygon pts;
    pts.append(QPoint(centerX - offset, initY));
    pts.append(QPoint(centerX + offset, initY));
    pts.append(QPoint(centerX, initY + offset));
    painter->drawPolygon(pts);

    //绘制文字
    QString strValue;
    if (percent) {
        double temp = value / (maxValue - minValue) * 100;
        strValue = QString("%1%").arg(temp, 0, 'f', 0);
    } else {
        strValue = QString("%1").arg((double)value, 0, 'f', 0);
    }

    painter->setPen(textColor);
    painter->drawText(rect, Qt::AlignCenter, strValue);

    painter->restore();
}

void ProgressTip::drawValue(QPainter *painter)
{
    painter->save();
    painter->setPen(Qt::NoPen);

    //定义了画刷则取画刷,可以形成渐变效果
    painter->setBrush(valueBrush == Qt::NoBrush ? valueColor : valueBrush);

    //计算当前值对应的百分比
    double step = value / (maxValue - minValue);
    int progress = (width() - padding * 2) * step;

    QRect rect(padding, (height() / 3) * 2, progress, height() / 3);
    painter->drawRoundedRect(rect, radius, radius);

    painter->restore();
}