c++ - 如何为小部件设置边框，继承自 QFrame？

Question

我创建了具有径向渐变的 LED 灯小部件（在互联网上找到示例）。它继承自 qwidget，我可以在其中使用的所有类型的边框都由 QPaint 提供。但是我需要更复杂的 LED 形状，我在 QFrame 类中看到了这种边框，我从它继承了我的小部件，但是当我想为我的小部件设置边框类型时，什么也没发生。paintEvent 方法可能有一些错误？

ledindicator.cpp

 #include "ledindicator.h"
 #include <QPainter>

  LedIndicator::LedIndicator(QWidget *parent) :
   QFrame(parent)
 {
  setFixedSize(218, 218);
  lit = false;
  ledOnColor=Qt::green;
  ledOffColor=Qt::red;
  ledOnPattern = Qt::SolidPattern;
  ledOffPattern = Qt::SolidPattern;
  ledSize=400;
}

void LedIndicator::paintEvent(QPaintEvent *) {
   QPainter p(this);

 //QPen pen(Qt::black, 3, Qt::SolidLine, Qt::FlatCap, Qt::RoundJoin);
 //p.setPen(pen);

  QRadialGradient radialGradient(ledSize, ledSize, ledSize , ledSize + 7, ledSize + 7);
  radialGradient.setColorAt(0.0, Qt::white);
  radialGradient.setColorAt(0.2, Qt::green);
  radialGradient.setColorAt(1.0, Qt::green);

  if (lit){
     p.setBrush(QBrush( radialGradient)); //
  } else {
    p.setBrush(QBrush( radialGradient)); //ledOffColor,
  }

  p.drawRect(0,0,ledSize,ledSize);
  QFrame::setFrameStyle( QFrame::Box | QFrame::Raised);//setFrameStyle(QFrame::Box|QFrame::Raised);
  QFrame::setLineWidth(0);
  QFrame::setMidLineWidth(3);
  //setLineWidth(0);
  //
  //setFrameShape( QFrame::Shape);
}

void LedIndicator::switchLedIndicator() {
  lit = ! lit;
  repaint();
}
void LedIndicator::setState(bool state)
{
  lit = state;
  repaint();
}
void LedIndicator::toggle()
{
  lit = ! lit;
  repaint();
}

void LedIndicator::setOnColor(QColor onColor)
{
  ledOnColor=onColor;
  repaint();
}
void LedIndicator::setOffColor(QColor offColor)
{
  ledOffColor=offColor;
  repaint();
}
void LedIndicator::setOnPattern(Qt::BrushStyle onPattern)
{
  ledOnPattern=onPattern;
  repaint();
}
void LedIndicator::setOffPattern(Qt::BrushStyle offPattern)
{
  ledOffPattern=offPattern;
  repaint();
}
void LedIndicator::setLedSize(int size)
{
  ledSize=size;
  setFixedSize(size+10, size+10);
  repaint();
}

ledindicator.h

#ifndef LEDINDICATOR_H
#define LEDINDICATOR_H

#include <QWidget>
#include <QRadialGradient>
#include <QPen>
#include <QLabel>

class LedIndicator: public QFrame {
    Q_OBJECT
  public:
    LedIndicator(QWidget *parent = 0);
    void setState(bool state);
    void toggle();
    void setOnColor(QColor onColor);
    void setOffColor(QColor offColor);
    void setOnPattern(Qt::BrushStyle onPattern);
    void setOffPattern(Qt::BrushStyle offPattern);
    void setLedSize(int size);

  public slots:
    void switchLedIndicator();
  protected:
    void paintEvent(QPaintEvent *);
  private:
    QPen pen;
    bool lit;
    QColor ledOnColor;
    QColor ledOffColor;
    Qt::BrushStyle ledOnPattern;
    Qt::BrushStyle ledOffPattern;
    int ledSize;
};

#endif // LEDINDICATOR_H

Answer 1

QFrame您必须在您通过的边缘内的矩形顶部绘制contentsRect()。setFrameStyle()、setLineWidth()和方法在构造函数中执行此setLineWidth()操作，因为您只会调用它一次。

ledindicator.h

#ifndef LEDINDICATOR_H
#define LEDINDICATOR_H

#include <QFrame>

class LedIndicator : public QFrame
{
    Q_OBJECT
    Q_PROPERTY(bool state READ state WRITE setState)
    Q_PROPERTY(QColor onColor READ onColor WRITE setOnColor)
    Q_PROPERTY(QColor offColor READ offColor WRITE setOffColor)
    Q_PROPERTY(Qt::BrushStyle onPattern READ onPattern WRITE setOnPattern)
    Q_PROPERTY(Qt::BrushStyle offPattern READ offPattern WRITE setOffPattern)
    Q_PROPERTY(int side READ side WRITE setSide)
public:
    LedIndicator(QWidget *parent = nullptr);
    bool state() const;
    void setState(bool state);

    QColor onColor() const;
    void setOnColor(const QColor &onColor);

    QColor offColor() const;
    void setOffColor(const QColor &offColor);

    Qt::BrushStyle onPattern() const;
    void setOnPattern(const Qt::BrushStyle &onPattern);

    Qt::BrushStyle offPattern() const;
    void setOffPattern(const Qt::BrushStyle &offPattern);
    int side() const;
    void setSide(int side);
public slots:
    void toggle();
protected:
    void paintEvent(QPaintEvent *event);
private:
    bool m_state;
    QColor m_onColor;
    QColor m_offColor;
    Qt::BrushStyle m_onPattern;
    Qt::BrushStyle m_offPattern;
    int m_side;
};

#endif // LEDINDICATOR_H

ledindicator.cpp

#include "ledindicator.h"

#include <QPainter>

LedIndicator::LedIndicator(QWidget *parent) :
    QFrame(parent),
    m_state(false),
    m_onColor(Qt::green),
    m_offColor(Qt::red),
    m_onPattern(Qt::SolidPattern),
    m_offPattern(Qt::SolidPattern)
{
    setFrameStyle( QFrame::Box | QFrame::Raised);
    setLineWidth(0);
    setMidLineWidth(3);
}

void LedIndicator::paintEvent(QPaintEvent *event) {
    QFrame::paintEvent(event);
    QPainter p(this);
    QBrush b = m_state ? QBrush(m_onColor, m_onPattern): QBrush(m_offColor, m_offPattern);
    p.fillRect(contentsRect(), b);
}

int LedIndicator::side() const
{
    return m_side;
}

void LedIndicator::setSide(int side)
{
    m_side = side;
    setFixedSize(side, side);
}

Qt::BrushStyle LedIndicator::offPattern() const
{
    return m_offPattern;
}

void LedIndicator::setOffPattern(const Qt::BrushStyle &offPattern)
{
    m_offPattern = offPattern;
}

void LedIndicator::toggle()
{
    setState(!state());
}

Qt::BrushStyle LedIndicator::onPattern() const
{
    return m_onPattern;
}

void LedIndicator::setOnPattern(const Qt::BrushStyle &onPattern)
{
    m_onPattern = onPattern;
}

QColor LedIndicator::offColor() const
{
    return m_offColor;
}

void LedIndicator::setOffColor(const QColor &offColor)
{
    m_offColor = offColor;
    update();
}

QColor LedIndicator::onColor() const
{
    return m_onColor;
}

void LedIndicator::setOnColor(const QColor &onColor)
{
    m_onColor = onColor;
    update();
}

bool LedIndicator::state() const
{
    return m_state;
}

void LedIndicator::setState(bool state)
{
    m_state = state;
    update();
}