为升级的小部件设置父级QWidget

Question

I have a Main QWidget which contains three promoted widgets: A derived from QGraphicsView , B derived from QLabel and C derived from QWidget .
On application exit I need B and C to be destroyed before A , but I figured out that since A , B and C parent is automatically set to Main , A is destroyed first. This can be solved setting A as B and C parent.

The generated ui_ProjectName.h file has:

a = new A(Main);
b = new B(Main);
c = new C(Main);

But it should be:

a = new A(Main);
b = new B(a);
c = new C(a);

Is there a way to do this from Qt Designer directly to generate the correct ui_ProjectName.h ?

Answer 1

If your 3 widgets do not belong to same layout you can manually edit .ui file to assign proper parent to a widget. To make widget A a parent for a widget B you can just cut <widget> tag that belongs to B and paste it inside A 's <widget> tag. Like this:

<widget class="QWidget" name="A">
    <widget class="QWidget" name="B">
       ...
    </widget>
</widget>

Note that QtCreator has a legal way to edit .ui files: click right mouse button on .ui file and then choose "Open With -> Plain Text Editor".

But pay attention : this will break layout rules if you have them. If you do not want to break layout for this case you probably can try reassign parents in runtime via code:

bWidget->setParent(aWidget);
cWidget->setParent(aWidget);

In this case it doesn't actually matter what code was generated in ui_*.h file — you will reset it.