How to reference the calling object in QML

Question

Is there a way to get a reference to the calling object in QML? I'm looking at something which is equivalent to the 'this' pointer in QML

Example: Say I have a component which serves as a backend for a graphical element such as a seekbar for a video player. This backend will take in the current and total durations of the video as input and periodically provide an update to the graphical seekbar. Now if there is a signal handler in this backend for a signal which sends current and total durations , it might look something like this:

Connections {
  target: sender //this

  onSendSeekUpdate()
  {
    //do something
  } 
}

Of course I guess this can be implemented in C++ and then imported into QML. But I was just wondering if QML also supports this? So that I can straight away write such hooks in QML.

If my understanding is correct, this is what you are trying to say. "A slot (the backend, you mentioned) which is capable of receiving current and total duration of video file, and process 'something' to provide an update to the graphical seek bar like 'remaining time' and 'seek bar placement'". As fas as I know you cannot define a QML component like a function. Which accepts values (as arguments) and do some process(like updating the graphical seekbar), finally returning a value. But you can do that in Javascript function or C++ methods. — RajaRaviVarma

TheBootroo TheBootroo · Accepted Answer · 2013-03-27T20:56:59

In QML you can use any id as a pointer, as well as any QObject derived type property, so in your code example, we can change the target of the Connection dynamically and still use the same var in the signal handler to point on the sender :

Connections {
    target: myitem; // change it when you need
    onMySignal: {
        target.doSomething(); // just use target here as it points on the listened object
        // it's just like 'sender()' in Qt/C++
    }
}

Not sure it was what you were asking for, but I tried to understand your explanation ;-)

How to reference the calling object in QML

1 Answers