为什么我的属性在我的自定义qt小部件中总是空的

Question

我尝试为Qt Designer创建一个简单的小部件。当我设置一个房产时，在我尝试阅读我的房产之后或很久之后，她总是空着。

setProperty("iconConnection", QIcon("toto.png"));
qDebug() << property("iconConnection");

我尝试不同的测试，一切都没有做。也许我不理解Q_PROPERTY的概念

完整代码：

QKSwitchButton.h

#pragma once

// Qt
#include <QStateMachine>
#include <QPushButton>
#include <QState>
#include <QVariant>
#include <QDebug>

#include <QtUiPlugin/QDesignerExportWidget>

class QDESIGNER_WIDGET_EXPORT QKSwitchButton: public QPushButton
{
    Q_OBJECT
    Q_PROPERTY(QIcon      iconDisconnected          READ iconDisconnected       WRITE setIconDisconnected       NOTIFY iconDisconnectedChanged)
    Q_PROPERTY(QIcon      iconConnection            READ iconConnection         WRITE setIconConnection         NOTIFY iconConnectionChanged)
    Q_PROPERTY(QIcon      iconConnected             READ iconConnected          WRITE setIconConnected          NOTIFY iconConnectedChanged)
    Q_PROPERTY(QIcon      iconDisconnection         READ iconDisconnection      WRITE setIconDisconnection      NOTIFY iconDisconnectionChanged)

public:
    QKSwitchButton(QWidget * parent = 0);
    ~QKSwitchButton();

    QIcon iconDisconnected();
    QIcon iconConnection();
    QIcon iconConnected();
    QIcon iconDisconnection();

public slots:
    void setIconDisconnected(QIcon icon);
    void setIconConnection(QIcon icon);
    void setIconConnected(QIcon icon);
    void setIconDisconnection(QIcon icon);

signals:
    void iconDisconnectedChanged(QIcon icon);
    void iconConnectionChanged(QIcon icon);
    void iconConnectedChanged(QIcon icon);
    void iconDisconnectionChanged(QIcon icon);

private:
    QStateMachine* m_machine;
    QState *m_stateOFF;
    QState *m_stateConnection;
    QState *m_stateON;
    QState *m_stateDisconnection;

    QIcon m_iconDisconnected;
    QIcon m_iconConnection;
    QIcon m_iconConnected;
    QIcon m_iconDisconnection;

};

QKSwitchButton.cpp

#include "QKSwitchButton.h"

// Qt
#include <QState>
#include <QStateMachine>
#include <QEventTransition>
#include <QEvent>
#include <QDebug>

// 
#include "QKEvent.h"

#include <QMetaProperty>

#include <vector>
#include <utility>
#include <algorithm>

static void dump_props(QObject *o)
{
  auto mo = o->metaObject();
  qDebug() << "## Properties of" << o << "##";
  do {
    qDebug() << "### Class" << mo->className() << "###";
    std::vector<std::pair<QString, QVariant> > v;
    v.reserve(mo->propertyCount() - mo->propertyOffset());
    for (int i = mo->propertyOffset(); i < mo->propertyCount();
          ++i)
      v.emplace_back(mo->property(i).name(),
                     mo->property(i).read(o));
    std::sort(v.begin(), v.end());
    for (auto &i : v)
      qDebug() << i.first << "=>" << i.second;
  } while ((mo = mo->superClass()));
}

QKSwitchButton::QKSwitchButton(QWidget * parent)
    : QPushButton(parent)
{
    m_machine = new QStateMachine(this);

    this->setText("");

    // States
    m_stateOFF = new QState();    
    m_stateConnection = new QState();    
    m_stateON = new QState();
    m_stateDisconnection = new QState();


    // Changes of states

    QEventTransition *connectionTransition = new QEventTransition(this, QEvent::MouseButtonPress);
    connectionTransition->setTargetState(m_stateConnection );
    m_stateOFF->addTransition(connectionTransition);

    QKTransition *connectedTransition = new QKTransition(QKEvent::DeviceConnected );
    connectedTransition->setTargetState(m_stateON );
    m_stateConnection->addTransition( connectedTransition );

    QKTransition *connectionFailedTransition = new QKTransition(QKEvent::DeviceConnectionFailed);
    connectionFailedTransition->setTargetState(m_stateOFF);
    m_stateConnection->addTransition(connectionFailedTransition);

    QEventTransition *disconnectionTransition = new QEventTransition(this, QEvent::MouseButtonPress);
    disconnectionTransition->setTargetState(m_stateDisconnection);
    m_stateON->addTransition(disconnectionTransition);

    QKTransition *disconnectedTransition = new QKTransition(QKEvent::DeviceDisconnected );
    disconnectedTransition->setTargetState(m_stateOFF);
    m_stateDisconnection->addTransition(disconnectedTransition);

    m_machine->addState(m_stateON);
    m_machine->addState(m_stateOFF);
    m_machine->addState(m_stateConnection);
    m_machine->addState(m_stateDisconnection);

    //this->setIcon(QIcon(":/icons/ribbon/ON-OFF-off.png"));

    m_machine->setInitialState(m_stateOFF);

    m_machine->start();

}


QKSwitchButton::~QKSwitchButton()
{
}


QIcon QKSwitchButton::iconDisconnected()
{
    return m_iconDisconnected;
}
QIcon QKSwitchButton::iconConnection()
{
    return m_iconConnection;
}
QIcon QKSwitchButton::iconConnected()
{
    return m_iconConnected;
}
QIcon QKSwitchButton::iconDisconnection()
{
    return m_iconDisconnection;
}

void QKSwitchButton::setIconDisconnected(QIcon icon)
{
    dump_props(this);

    m_stateOFF->assignProperty(this, "icon", icon);
    const QMetaObject *mo = metaObject();
    QMetaProperty prop = mo->property(mo->indexOfProperty("iconConnection"));
    qDebug() << property(prop.name());
    qDebug() << "============================";


    setProperty("iconConnection", QIcon("toto.png"));
    qDebug() << property("iconConnection");

    emit iconDisconnectedChanged(icon);
}
void QKSwitchButton::setIconConnection(QIcon icon)
{
    m_stateConnection->assignProperty(this, "icon", icon);
    emit iconConnectionChanged(icon);
}
void QKSwitchButton::setIconConnected(QIcon icon)
{
    m_stateON->assignProperty(this, "icon", icon);
    emit iconConnectedChanged(icon);
}
void QKSwitchButton::setIconDisconnection(QIcon icon)
{
    m_stateDisconnection->assignProperty(this, "icon", icon);
    emit iconDisconnectionChanged(icon);
}

QKSwitchButtonPlugin.h：

#pragma once

#include <QtUiPlugin/QDesignerCustomWidgetInterface>

class QIcon;
class QWidget;

class QKSwitchButtonPlugin : public QObject, public QDesignerCustomWidgetInterface
{
    Q_OBJECT
    //Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QDesignerCustomWidget")
    Q_PLUGIN_METADATA(IID "com.toto.plugin.Qt.SwitchButton" FILE "QKSwitchButtonMetadata.json") // It's important to change the version name after every modification.
    Q_INTERFACES(QDesignerCustomWidgetInterface)

public:
    explicit QKSwitchButtonPlugin(QObject *parent = 0);

    bool isContainer() const override;
    bool isInitialized() const override;
    QIcon icon() const override;
    QString domXml() const override;
    QString group() const override;
    QString includeFile() const override;
    QString name() const override;
    QString toolTip() const override;
    QString whatsThis() const override;
    QWidget *createWidget(QWidget *parent) override;
    void initialize(QDesignerFormEditorInterface *formEditor) override;

private slots:
    void iconDisconnectedChanged(QIcon icon);
    /*void iconConnectionChanged(QIcon icon);
    void iconConnectedChanged(QIcon icon);
    void iconDisconnectionChanged(QIcon icon);*/

 private:
     bool initialized;
};

QKSwitchButtonPlugin.cpp：

#include <QtDesigner/QExtensionFactory>
#include <QtDesigner/QExtensionManager>
#include <QtDesigner/QDesignerFormEditorInterface>
#include <QtDesigner/QDesignerFormWindowInterface>
#include <QtDesigner/QDesignerContainerExtension>
#include <QtDesigner/QDesignerPropertySheetExtension>

#include <QIcon>
#include <QtPlugin>

#include "QKSwitchButton.h"
#include "QKSwitchButtonPlugin.h"

QKSwitchButtonPlugin::QKSwitchButtonPlugin(QObject *parent)
    : QObject(parent)
    , initialized(false)
{
}

QString QKSwitchButtonPlugin::name() const
{
    return QLatin1String("QKSwitchButton");
}

QString QKSwitchButtonPlugin::group() const
{
    return QLatin1String("toto");
}

QString QKSwitchButtonPlugin::toolTip() const
{
    return QString();
}

QString QKSwitchButtonPlugin::whatsThis() const
{
    return QString();
}

QString QKSwitchButtonPlugin::includeFile() const
{
    return QLatin1String("QKSwitchButton.h");
}

QIcon QKSwitchButtonPlugin::icon() const
{
    return QIcon();
}

bool QKSwitchButtonPlugin::isContainer() const
{
    return false;
}

QWidget *QKSwitchButtonPlugin::createWidget(QWidget *parent)
{
    QKSwitchButton *widget = new QKSwitchButton(parent);
    connect(widget, &QKSwitchButton::iconDisconnectedChanged, this, &QKSwitchButtonPlugin::iconDisconnectedChanged);

    return widget;
}

bool QKSwitchButtonPlugin::isInitialized() const
{
    return initialized;
}

void QKSwitchButtonPlugin::initialize(QDesignerFormEditorInterface *formEditor )
{
    Q_UNUSED(formEditor)
    if (initialized)
        return;

    initialized = true;
}

QString QKSwitchButtonPlugin::domXml() const
{
    return QLatin1String("\
<ui language=\"c++\">\
    <widget class=\"QKSwitchButton\" name=\"qkswitchbutton\">\
        <property name=\"geometry\">\
            <rect>\
                <x>0</x>\
                <y>0</y>\
                <width>63</width>\
                <height>30</height>\
            </rect>\
        </property>\
    </widget>\
    <customwidgets>\
        <customwidget>\
            <class>QKSwitchButton</class>\
            <extends>QPushButton</extends>\
        </customwidget>\
    </customwidgets>\
</ui>");
}


void QKSwitchButtonPlugin::iconDisconnectedChanged(QIcon icon)
{
    setProperty("iconDisconnected", icon);
}