如何创建自定义UI的QT插件？

#ifndef MYPLUGIN_H
#define MYPLUGIN_H

#include <QtUiPlugin/QDesignerCustomWidgetInterface>

class MyPlugin : public QObject, public QDesignerCustomWidgetInterface
{
    Q_OBJECT
    Q_INTERFACES(QDesignerCustomWidgetInterface)

public:
    MyPlugin(QObject *parent = nullptr);

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

private:
    bool initialized = false;
};

#endif // MYPLUGIN_H

#include "myplugin.h"
#include "mywidget.h"

MyPlugin::MyPlugin(QObject *parent)
    : QObject(parent)
{
}

QString MyPlugin::name() const
{
    return "MyWidget";
}

QString MyPlugin::group() const
{
    return "Custom Widgets";
}

QString MyPlugin::toolTip() const
{
    return "My custom widget";
}

QString MyPlugin::whatsThis() const
{
    return "A custom widget for demonstration";
}

QString MyPlugin::includeFile() const
{
    return "mywidget.h";
}

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

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

QWidget *MyPlugin::createWidget(QWidget *parent)
{
    return new MyWidget(parent);
}

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

void MyPlugin::initialize(QDesignerFormEditorInterface *core)
{
    Q_UNUSED(core);
    initialized = true;
}

#ifndef MYWIDGET_H
#define MYWIDGET_H

#include <QWidget>

class MyWidget : public QWidget
{
    Q_OBJECT

public:
    MyWidget(QWidget *parent = nullptr);
};

#endif // MYWIDGET_H

#include "mywidget.h"

MyWidget::MyWidget(QWidget *parent)
    : QWidget(parent)
{
    // 自定义UI的实现
}