How create shared library in QT/QML - qt

Question

I have 4 qml files and one main.cpp to load qml file.
Is it possible for me to create 1 dll file for those 4 qml file.
And use it in different application if so how to do that.

Answer 1

As already said, there is no need for embedding qml files only in a library. But of course you have the right to do all you want, even that. I know at least 2 ways to do that:
1. Create binary resource file
Prepare resource file containing qml files and then compile it:
rcc -binary plugin.qrc -o plugin.rcc
Now you can include this file into your application :
QResource::registerResource("plugin.rcc");
and use it as regular qrc file:
QResource::registerResource(qApp->applicationDirPath() + "/plugin.rcc");
QQuickView *view = new QQuickView();
view->setSource(QUrl("qrc:/qml/myfile.qml"));
Here qml/ is prefix in resource file.
2. Shared libraryAnother way is to create a shared library containing the same resource file. For example your plugin's shared library implements following interface:
interface.h
#ifndef PLUGIN_INTERFACE_H
#define PLUGIN_INTERFACE_H
#include <QString>
#include <QObject>
class PluginInterface
{
public:
virtual ~PluginInterface() {}
virtual QByteArray getQML(const QString &name) = 0;
};
#define PluginInterface_iid "org.qt-project.PluginInterface"
Q_DECLARE_INTERFACE(PluginInterface, PluginInterface_iid)
#endif
and its implementation is:
QByteArray PluginImpl::getQML(const QString &name)
{
QFile file(":/qml/" + name);
if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
return QByteArray();
return file.readAll();
}
Now, in your application you load your plugin and get its resource as a string:
QDir pluginsDir(qApp->applicationDirPath());
QPluginLoader pluginLoader(pluginsDir.absoluteFilePath("plugin.dll"));
QObject *plugin = pluginLoader.instance();
if (plugin) {
PluginInterface *pluginInstance = qobject_cast<PluginInterface *>(plugin);
if (pluginInstance) {
QByteArray content = pluginInstance->getQML("file1.qml");
QQuickView *view = new QQuickView();
QQmlComponent component(view->engine());
component.setData(content, QUrl());
QQuickItem *childItem = qobject_cast<QQuickItem*>(component.create());
childItem->setParentItem(view->contentItem());
QWidget *container = QWidget::createWindowContainer(view);
container->setFocusPolicy(Qt::TabFocus);
ui->verticalLayout->addWidget(container);
}
}
But pay attention, when you deploy your application you anyway have to copy all qml system files, like #QTPATH/qml/QtQml, #QTPATH/qml/QtQuick.2, #QTPATH/qml/QtQuick.2 etc.
Links:
Resource compiler
Same theme
Plugin example

Answer 2

Have a look at the documentation for QML Modules
There are options for QML-only modules, C++ only and mixed mode.