[Qt-qml] component.createObject has gained a mandatory argument

[Alan Alpert]

Hi,

Another minor change to QML that just occurred is that the createObject 
function on Component now requires the parent of the new item to be passed in 
as an argument. 

For graphical objects (the common case) a common mistake is to not parent a 
dynamically created item. Since you almost always want to add a parent, and 
it's hard for a beginner to realize what they've done wrong when they forget, 
a parent is now a required argument. The function will also set the parent on 
the created object. Note that because the argument is required, an error is 
thrown if you try to call createObject without arguments like old code did.

All the cases we had set the parent on the next line, so the change that you'd 
probably need to get your code working again would be as in the example below.

var a = component.createObject();
a.parent = parentItem;

becomes

var a = component.createObject(parentItem);

If you do not want to set the parent there you can pass null into the 
function, but at least you've made that choice explictly.

-- 
Alan Alpert
Software Engineer
Nokia, Qt Development Frameworks