Parent-Child Relationship

[kumararajas]

@SGaist
Example, here is how UI is designed

State 1

|-------------------|
|      W1           |
|-------------------|
|       W2          |
|-------------------|
|              Open |
|       W3          |
|                   |
|-------------------|

W1 & W2 are the other widgets
W3 has a open button which would bring up the child widget W31.

After clicking on the Open button

State 2

|-------------------|
|      W1           |
|-------------------|
|       W2          |
|-------------------|
|                 X |
|       W31         |
|                   |
|-------------------|

W31 has some details to be shown to the user. On pressing X button button, UI would go back to State 1.

In this scenario, When Open button is clicked, I want to hide W3 and show W31.

As I have mentioned above, when I call W3 hide, W31 's show crashes the application.

[SGaist]

Wouldn't it make more sense to use a QStackedWidget ?

[kumararajas]

@SGaist Not thought about it. But, this is more like a pop-up widget comes up when clicking on 'open' and gets closed when we close it.

[SGaist]

Ok, so since it's a popup, why hide the other widget ?

[kumararajas]

@SGaist That's a good point Sam. Actually, I don't need to hide the parent, when the child is being shown.
It was an attempt to understand if I can hide the parent when the child is being shown.

Looks like we can't hide the parent when the child is being shown. I was trying to understand the reason and how Qt handles it.

[J.Hilk]

@kumararajas said in Parent-Child Relationship:

Looks like we can't hide the parent when the child is being shown

You should be able to, when you hide the parent, after the child is actually shown

[kumararajas]

@J-Hilk

void ParentWidget::buttonClicked()
{
    // create child UI
    childUI = new ChildWidget(this);

     this->hide();
    childUI->show();
}

In the code snippet that I have mentioned above,
After this->hide which hides the parent, child->show does not bring up the child UI. When I print the visibility state, it returns false

[J.Hilk]

@kumararajas said in Parent-Child Relationship:

In the code snippet that I have mentioned above,
After this->hide which hides the parent, child->show does not bring up the child UI. When I print the visibility state, it returns false

I said, show it first, then hide it

void ParentWidget::buttonClicked()
{
    // create child UI
    childUI = new ChildWidget(this);

    childUI->show();
    this->hide();
}

---

actually now that I read that, IIRC then the parent propagates the hide event to all it's (widget) children 🤔
So it shouldn't work

---

void ParentWidget::buttonClicked()
{
    // create child UI
    childUI = new ChildWidget(this);

    childUI-> setWindowModality(Qt::ApplicationModal);
    childUI->show();
    this->hide();
}

could work,
however, I haven't yet tested it

[kumararajas]

@J-Hilk said in Parent-Child Relationship:

childUI-> setWindowModality(Qt::ApplicationModal);

I shall test and keep you posted with the results. Thank you.

[kumararajas]

@J-Hilk @SGaist I have moved on with Sam's approach on why to hide the parent widget when it is being a pop-up. It worked for me, I couldn't test the windowModality.

Thank you for the help.

--Kumara