Animated Child Widget

[elemings]

I have the following simple little widget:

AnimatedSquare.h
AnimatedSquare.cpp

Works fine as a top-level widget. As a child widget though, it doesn't work.

What's wrong with it? Any help appreciated.

[amleto]

the problem is you're using (actually, abusing) the palette .

#if !defined ANIMATED_SQUARE_H
#  define ANIMATED_SQUARE_H
 
#  include <QtGui/QPalette>
#  include <QtGui/QWidget>
 
#include <QVariant>
 
class QPropertyAnimation;
 
/**
 * A square that transitions from one color to another.
 */
class AnimatedSquare
    : public QWidget
{
    Q_OBJECT
 
    Q_PROPERTY (QColor animColor
                READ animColor WRITE setAnimColor)
    Q_PROPERTY (int animDuration
                READ animDuration WRITE setAnimDuration)
 
public:
 
    AnimatedSquare (QWidget* = 0);
    ~AnimatedSquare();
 
    QSize minimumSizeHint() const;
    QSize sizeHint() const;
 
    void setAnimColors (const QColor&, const QColor&);
    QColor animColor() const;
    void setAnimColor (const QColor&);
    int animDuration() const;
    void setAnimDuration (int);
 
    void start();
 
protected:
 
    void paintEvent (QPaintEvent*);
 
private:
 
    QPropertyAnimation* animation;
    int duration;
 
    QVariant m_val;
};
 
inline QSize
AnimatedSquare::minimumSizeHint() const
{
    return QSize (50, 50);
}
 
inline QSize
AnimatedSquare::sizeHint() const
{
    return minimumSizeHint();
}
 
inline QColor
AnimatedSquare::animColor() const
{
    return m_val.value<QColor>();
}
 
inline int
AnimatedSquare::animDuration() const
{
    return duration;
}
 
inline void
AnimatedSquare::setAnimDuration (int milliseconds)
{
    duration = milliseconds;
}
 
#endif // !defined ANIMATED_SQUARE_H

#if !defined ANIMATED_SQUARE_H
#  define ANIMATED_SQUARE_H

#  include <QtGui/QPalette>
#  include <QtGui/QWidget>

#include <QVariant>

class QPropertyAnimation;

/**
 * A square that transitions from one color to another.
 */
class AnimatedSquare
    : public QWidget
{
    Q_OBJECT

    Q_PROPERTY (QColor animColor
                READ animColor WRITE setAnimColor)
    Q_PROPERTY (int animDuration
                READ animDuration WRITE setAnimDuration)

public:

    AnimatedSquare (QWidget* = 0);
    ~AnimatedSquare();

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

    void setAnimColors (const QColor&, const QColor&);
    QColor animColor() const;
    void setAnimColor (const QColor&);
    int animDuration() const;
    void setAnimDuration (int);

    void start();

protected:

    void paintEvent (QPaintEvent*);

private:

    QPropertyAnimation* animation;
    int duration;

    QVariant m_val;
};

inline QSize
AnimatedSquare::minimumSizeHint() const
{
    return QSize (50, 50);
}

inline QSize
AnimatedSquare::sizeHint() const
{
    return minimumSizeHint();
}

inline QColor
AnimatedSquare::animColor() const
{
    return m_val.value<QColor>();
}

inline int
AnimatedSquare::animDuration() const
{
    return duration;
}

inline void
AnimatedSquare::setAnimDuration (int milliseconds)
{
    duration = milliseconds;
}

#endif // !defined ANIMATED_SQUARE_H

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#include <QtCore/QPropertyAnimation>
#include <QtGui/QPainter>
 
#include <QPaintEvent>
#include <QColor>
#include <QDebug>
 
#include "AnimatedSquare.h"
 
AnimatedSquare::AnimatedSquare (QWidget* parent)
    : QWidget (parent)
    , animation (new QPropertyAnimation (this, "animColor"))
    , duration (1000)
{
    animation->setDuration(duration);
    animation->setLoopCount (-1); // infinite
}
 
void AnimatedSquare::paintEvent(QPaintEvent* e)
{
    QPainter painter (this);
    QColor c;
    if(m_val.canConvert<QColor>())
        c = m_val.value<QColor>();
 
    painter.fillRect(rect(), c);
}
 
void AnimatedSquare::setAnimColors (const QColor& begin, const QColor& end)
{
    animation->setStartValue(begin);
    animation->setEndValue(end);
}
 
void AnimatedSquare::start()
{
    animation->start();
}
 
void AnimatedSquare::setAnimColor (const QColor& newColor)
{
    m_val = newColor;
    update();
}
 
AnimatedSquare::~AnimatedSquare()
{
    delete animation;
}

#include <QtCore/QPropertyAnimation>
#include <QtGui/QPainter>

#include <QPaintEvent>
#include <QColor>
#include <QDebug>

#include "AnimatedSquare.h"

AnimatedSquare::AnimatedSquare (QWidget* parent)
    : QWidget (parent)
    , animation (new QPropertyAnimation (this, "animColor"))
    , duration (1000)
{
    animation->setDuration(duration);
    animation->setLoopCount (-1); // infinite
}

void AnimatedSquare::paintEvent(QPaintEvent* e)
{
    QPainter painter (this);
    QColor c;
    if(m_val.canConvert<QColor>())
        c = m_val.value<QColor>();

    painter.fillRect(rect(), c);
}

void AnimatedSquare::setAnimColors (const QColor& begin, const QColor& end)
{
    animation->setStartValue(begin);
    animation->setEndValue(end);
}

void AnimatedSquare::start()
{
    animation->start();
}

void AnimatedSquare::setAnimColor (const QColor& newColor)
{
    m_val = newColor;
    update();
}

AnimatedSquare::~AnimatedSquare()
{
    delete animation;
}

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