QQuickPaintedItem from .qml file

ODБOï

Hi,
I have created a little test application with .qml files avalables for the user so he can edit and change visual aspect of the application.

I dit that by subclassing 'QQuickPaintedItem' like this :
// QMProgressBar .h

class QMProgressBar :  public QQuickPaintedItem
{
    Q_OBJECT
public:
    QMProgressBar(QQuickItem *parent = 0);

private:
        QQuickItem* userItem;
       // void paint(QPainter *painter);
};

//QMProgressBar.cpp

QMProgressBar::QMProgressBar(QQuickItem *parent):QQuickPaintedItem(parent)
{

    QString homeLocation = QStandardPaths::locate(QStandardPaths::DocumentsLocation, QString(), QStandardPaths::LocateDirectory);
    homeLocation.append("QML_CUSTOM_ITEM/Customizable.qml");
    QQmlEngine qengine;
    QQmlComponent component(&qengine,QUrl::fromUserInput(homeLocation));
    QFile file(homeLocation);

    if( file.exists()){
        qDebug()<< "User file found..."<< homeLocation ;
        userItem = qobject_cast<QQuickItem*>(component.create());
        userItem->setParentItem(this)
    }    
}

//main.cpp

qmlRegisterType<QMProgressBar>("QMProgressBar", 1, 0, "Bar");

//main.qml

 Bar{
            id:bar
            height: 150
            width: 150
        }

This works but i have at least 1 probleme :

if 'Customizable.qml' contains just Rectangles/Texts/.. (not dynamic behavior) it will work.

exemple Customizable.qml:

Item{
    Rectangle{
        id:r
       color : "red"
       rotation : 45
   }
}

But if 'Customizable.qml' contains some dynamic behavior, it will not work

exemple Customizable.qml:

Item{
    Rectangle{
        id:r
       color : "red"
       rotation : 45
   }
   Timer{
        running:true
        repeat:true
        interval : 500
        onTriggered: r.rotation+=10 // item will not rotate
    }
}

SGaist

Hi,

Why not use a Loader ?

ODБOï

@SGaist hi,
after your comment on my previous thread
https://forum.qt.io/topic/87077/qt-application-with-public-qml-code-that-user-can-edit/2

"One possible way is to copy the file you want to allow editing from the resource to a suitable writable location (see QStandardPaths).
Then you have to tell your application to load that file if it exists otherwise the one from the resource. "

I though the best solution was to do this by subclassing 'QQuickPaintedItem' ...

I will try to do the same thing using Loader, it seems easier in fact.

Thx!

ODБOï

Perfect, i dit it in 10 minutes with Loader !


    property Component qrcComponent
    property Component userComponent


    Component.onCompleted: {

        userComponent = Qt.createComponent("file:///C:/Users/userName/Documents/QML_CUSTOM_ITEM/Customizable.qml")
       //qrcComponent = Qt.createComponent("/Customizable.qml")

    }

    onUserComponentChanged: {
        if(userComponent.status==Component.Ready){
            l.sourceComponent = userComponent
        }
        else{
            qrcComponent = Qt.createComponent("/Customizable.qml")
            if(qrcComponent.status==Component.Ready){
                l.sourceComponent = qrcComponent
            }
        }
    }


        Loader{
            id:l
            height: 150
            width: 150
            anchors.centerIn: parent
           // source: "file:///C:/Users/userName/Documents/QML_CUSTOM_ITEM/Customizable.qml" ||  "/Customizable.qml"
        }

Thx

ODБOï

@SGaist said in QQuickPaintedItem from .qml file:

Why not use a Loader ?

FinalIy i did it with Loader , but is there a way to do the same thing with my QMProgressBar class ?

ODБOï

On my Loader exemple, Is it possible to Reload component runtime ?

    Button{
        text:"reload"
        onClicked: { /* RELOADING ? */
            userComponent = Qt.createComponent("file:///C:/Users/lagayev/Documents/QML_CUSTOM_ITEM/Customizable.qml");
        }
    }

If i edit 'Customizable.qml' while application is running, and click this 'reload' button 'Customizable.qml' is unchanged,
i have to quit and restart my app to see changes. Could you tell me Why ?

ODБOï

I tryed to clearComponentCache as it is described here :
http://doc.qt.io/qt-5/qqmlengine.html#clearComponentCache

class QmlEngineManager : public QQmlApplicationEngine
{
    Q_OBJECT
public:
    QmlEngineManager();

    Q_INVOKABLE void clearCache() {
        clearComponentCache();
        qDebug()<<"engine cleared !";
    }
};

Then in qml :

 Button{
        text:"reload"
        onClicked: { /* RELOADING ? */
             engineManager.clearCache()
            userComponent = Qt.createComponent("file:///C:/Users/lagayev/Documents/QML_CUSTOM_ITEM/Customizable.qml");
        }
    }

witout success.

SGaist

What about destroying userComponent before you create the new one ?

ODБOï

@SGaist with this code, when i start my app, it will create a component from file:///C:/Users/usr/Documents/QML_CUSTOM_ITEM/Customizable.qml if that file exists, else it will create component from /Customizable.qml

But when app is running, if i DELETE 'Customizable.qml' file from that path (file:///C:/Users/usr/Documents/QML_CUSTOM_ITEM/Customizable.qml) , and press 'Reload' button, the same .qml file is displayed !

It looks like content of a given path is calculated only when the application starts..?

What is the probleme here ?

   signal updateComponents()
    Button{
        text: "Reload"
        onClicked: {
            updateComponents()
        }
    }
    Component.onCompleted:updateComponents()
  
  onUpdateComponents: {
     var tmp =  Qt.createComponent("file:///C:/Users/usr/Documents/QML_CUSTOM_ITEM/Customizable.qml")
     if(tmp.status===Component.Ready){
                 l.sourceComponent = tmp
     }
     else{
             tmp=Qt.createComponent("/Customizable.qml")
             if(tmp.status===Component.Ready){
                  l.sourceComponent=tmp
               }
           }
            delete(tmp)
    }

    Loader{
        id:l
        height: 150
        width: 150
        anchors.centerIn: parent
    }

SGaist

I was rather thinking about what is described here.

ODБOï

@SGaist Hi,
I did that way too, but no success because

when my app calls :

  var component = Qt.createComponent("file:///C:/Users/user/Documents/QML_CUSTOM_ITEM/Destructible.qml")

inside that directory ("file:///C:/Users/user/Documents/QML_CUSTOM_ITEM") another file is created by qt, named

Destructible.qmlc ( 'c' like copy ? )

Next call 'Qt.createComponent()' loads that 'Destructible.qmlc'

SGaist

This presentation might help.