myitem.cxx

#include "myitem.hxx"

MyItem::MyItem(QQuickItem *parent):
  QQuickItem(parent)
{
  // By default, QQuickItem does not draw anything. If you subclass
  // QQuickItem to create a visual item, you will need to uncomment the
  // following line and re-implement updatePaintNode()
  
  // setFlag(ItemHasContents, true);
}

MyItem::~MyItem()
{
}

myitem.hxx

#ifndef MYITEM_H
#define MYITEM_H

#include <QQuickItem>

class MyItem : public QQuickItem
{
  Q_OBJECT
  Q_DISABLE_COPY(MyItem)
  
public:
  MyItem(QQuickItem *parent = 0);
  ~MyItem();
};

QML_DECLARE_TYPE(MyItem)

#endif // MYITEM_H

qmldir

module com.mycompany.qmlcomponents
plugin untitled

untitled.pro

TEMPLATE = lib
TARGET = untitled
QT += qml quick
CONFIG += qt plugin

TARGET = $$qtLibraryTarget($$TARGET)
uri = com.mycompany.qmlcomponents

# Input
SOURCES += \
    untitled_plugin.cxx \
    myitem.cxx

HEADERS += \
    untitled_plugin.hxx \
    myitem.hxx

OTHER_FILES = qmldir

!equals(_PRO_FILE_PWD_, $$OUT_PWD) {
    copy_qmldir.target = $$OUT_PWD/qmldir
    copy_qmldir.depends = $$_PRO_FILE_PWD_/qmldir
    copy_qmldir.commands = $(COPY_FILE) \"$$replace(copy_qmldir.depends, /, $$QMAKE_DIR_SEP)\" \"$$replace(copy_qmldir.target, /, $$QMAKE_DIR_SEP)\"
    QMAKE_EXTRA_TARGETS += copy_qmldir
    PRE_TARGETDEPS += $$copy_qmldir.target
}

qmldir.files = qmldir
unix {
    installPath = $$[QT_INSTALL_IMPORTS]/$$replace(uri, \\., /)
    qmldir.path = $$installPath
    target.path = $$installPath
    INSTALLS += target qmldir
}

untitled_plugin.cxx

#include "untitled_plugin.hxx"
#include "myitem.hxx"

#include <qqml.h>

void UntitledPlugin::registerTypes(const char *uri)
{
  // @uri com.mycompany.qmlcomponents
  qmlRegisterType<MyItem>(uri, 1, 0, "MyItem");
}

untitled_plugin.hxx

#ifndef UNTITLED_PLUGIN_H
#define UNTITLED_PLUGIN_H

#include <QQmlExtensionPlugin>

class UntitledPlugin : public QQmlExtensionPlugin
{
  Q_OBJECT
  Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QQmlExtensionInterface")
  
public:
  void registerTypes(const char *uri);
};

#endif // UNTITLED_PLUGIN_H