parentHierarchyChanged() - is it relevant name of method?

#1

Hello,
as name of method suggests it is called always the parent hierarchy is changed and no matter what child was added or removed.

So let’s say I have:
myChildComponent01
and
myChildComponent02
and
myParentComponent.

And now when I call:
myParentComponent.addAndMakeVisible(myChildComponent01);
then inside of it is called:
myChildComponent01.parentHierarchyChanged();

That’s great. And now myParentComponent is parent of myChildComponent01. So next I call:
myParentComponent.addAndMakeVisible(myChildComponent02);

As you can see I added another child, but I expect myParentComponent is also still parent of my first child. So I expect myChildComponent01.parentHierarchyChanged(); should be called again when another child is added. But it doesn’t happen.

Actually I prefer that behaviour, but I need to be sure parentHierarchyChanged() is called only once for each child, but the name of that method suggests it is called every time I add any childe to parent. So I am not sure what can I expect?

For any help great thanks in advance.
Best regards

#2

Language is a slippery thing. To me, this is very clear. Since the callback comes to a child component, it reflects changes to the parentage of that child. Creating a sibling does not change parentage of the first child, thus no callback.

And, while a function name should be useful, it’s not really documentation. The actual documentation for this function is clear on how it works. Your child component will get a callback when it’s parent hierarchy changes.

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#3

I wouldn’t expect this to happen - child components shouldn’t necessarily know about each other, only the parent should know about its children.

From the perspective of myChildComponent01 nothing has changed in the parent hierarchy - it’s parent hasn’t changed, nor any of its ancestors.

As @cpr2323 says, language can be tricky. To me, parentHierarchyChanged() implies that it will only ever be called when the parent, or an ancestor, changes for the given component. I wouldn’t except that to be called when another child is added to the parent.

#4

OK, great thanks for your answer. So it looks like I can be sure that:
myChildComponent.parentHierarchyChanged();
will be called only when myChildComponent is added/removed from it’s parent, but it is not called when other children are added/removed to the same parent.

That knowledge is enough for me. Thanks.

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