Loaded QQuickItem, how to set properties correct?

jpcolcom

How can i set the build in properties right?
I create a QQuickItem via QQmlComponent:

@LoadQuickItem::LoadQuickItem(QQmlEngine* engine, QQuickItem* parentView, QObject *parent) : QObject(parent) {

this->engine_ = engine;
this->parentView_ = parentView;
this->component_ = new QQmlComponent(engine, QUrl("qrc:///Item.qml"));
this->obj_ = new QObject();
this->continueLoading();
}

LoadQuickItem::~LoadQuickItem() {
delete this->component_;
delete this->obj_;
delete this->item_;
}

void LoadQuickItem::continueLoading() {
if (this->component_->isError()) {
qWarning() << this->component_->errors();
} else {
qDebug() << "Create QQuickItem";

  this->obj_ = this->component_->create();
  QQmlEngine::setObjectOwnership(this->obj_, QQmlEngine::CppOwnership);
  this->item_ = qobject_cast<QQuickItem*>(this->obj_);

  this->item_->setParentItem(this->parentView_);
  this

}
}@

Instance:
@
QQuickWindow wnd;
QQmlEngine engine;
LoadQuickItem* item1 = new LoadQuickItem(&engine, wnd.contentItem());
qDebug() << (item1->getItem()->setProperty("id", "item1") ? "Succes" : "Failed: item1->getItem()->setProperty("id", "item1")");
@

Item.qml

@import QtQuick 2.2
import QtQuick.Controls 1.2
import QtQuick.Controls.Styles 1.2

Button {
text:"Maximize"
tooltip:"Press me"
style: CustomStyle {}
}@

I want to set the property "id", but always get a false.
The property ought to be known?

Background, I would like load files via a QML and use them as templates. A QML file always contains only one control, eg a button.

Any idear?

sierdzio

id is not a property, it is not visible to public Qt API. You can not change it in C++. All remaining properties are available and you can change them as you wish.

p3c0

From the Doc:

bq. Once an object instance is created, the value of its id attribute cannot be changed. While it may look like an ordinary property, the id attribute is not an ordinary property attribute, and special semantics apply to it;

So you can't change it.

jpcolcom

Thanks.

how can I implement a dependency between two QQuickitems?
Like:

@
LoadQuickItem* item1 = new LoadQuickItem(&engine, wnd.contentItem());
LoadQuickItem* item2 = new LoadQuickItem(&engine, wnd.contentItem());
item2->getItem()->setProperty("y", "item1.height")
@

p3c0

You can use property() to get the height of other Item.

sierdzio

[quote author="p3c0" date="1409819479"]You can use property() to get the height of other Item.[/quote]

I think the OP wants to create a property binding from C++.

jpcolcom

[quote author="p3c0" date="1409819479"]You can use property() to get the height of other Item.[/quote]

Yes that works. But only in static way.

I mean this construct, in case of resizing the window.
@Button {
id: button1
width: parent.width / 100 * 20
height: parent.height / 100 * 20
}
Button {
id: button2
width: parent.width / 100 * 20
height: parent.height / 100 * 20
y: button1.height
}
@

sierdzio

-Here is an example on property bindings in C++. "Link":http://qt-project.org/doc/qt-5/qtqml-tutorials-extending-chapter3-bindings-example.html.-

Nope, sorry, that is not good enough.

p3c0

Connect the heightChanged signal to a slot, then get the height of item1 and then setProperty to item2.