Remove a QLayout from QGridLayout

[jpn]

QLayout::addChildLayout: layout "" already has a parent

Sounds like you are missing the

itemList[itemID]->setParent(0);

itemList[itemID]->setParent(0);

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which you had earlier..?

Could you describe the GUI you are building? Maybe there's another way for constructing something similar?

[grosem]

Sounds like you are missing the

itemList[itemID]->setParent(0);

itemList[itemID]->setParent(0);

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which you had earlier..?

Could you describe the GUI you are building? Maybe there's another way for constructing something similar?

I tried this too. But got a

X Error: BadWindow (invalid Window parameter) 3
Major opcode: 25 (X_SendEvent)
Resource id: 0x20000ad

Well, I have three frames, which have Items. These items are a QHBoxLayout which has 2 QLabels and a QSpinBox. The user should be able to drag these items between the three frames.

At first I tried the QItemView approach, but I wasn't able to do it the way I wanted.

I know my new approach using Layouts isn't the right one, but it is much simplier for me. Just the thing of removing does not work yet.

Thanks for your help

[jpn]

Yeah, the suggestion would have been using item views..

[grosem]

I never thought this reuse of Layouts would be a problem

[grosem]

I don't get it:

leftBox->addLayout(protoItem2);
leftBox->removeItem(protoItem2);
protoItem2=0;
delete protoItem2;

leftBox->addLayout(protoItem2);
leftBox->removeItem(protoItem2);
protoItem2=0;
delete protoItem2;

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Why is there still the layout in the leftBox??? Even more weird is that the added layout had two QLabels, but only one is still visible (the one with a QPixmap). leftBox->update() changes nothing.

[jpn]

leftBox->addLayout(protoItem2);
leftBox->removeItem(protoItem2);
protoItem2=0;
delete protoItem2; // <--- same as "delete 0;"

leftBox->addLayout(protoItem2);
leftBox->removeItem(protoItem2);
protoItem2=0;
delete protoItem2; // <--- same as "delete 0;"

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leftBox->addLayout(protoItem2);
leftBox->removeItem(protoItem2);
delete protoItem2; // delete first
protoItem2=0; // then set the pointer to 0

leftBox->addLayout(protoItem2);
leftBox->removeItem(protoItem2);
delete protoItem2; // delete first
protoItem2=0; // then set the pointer to 0

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[grosem]

ok, that's of course true, but unfortunatly that does not change something.

I did following: The Items I add to the QGridLayout are from a class derived from QHBoxLayout. I added two QLabels to this class and added them in the Constructor to the QHBoxLayout. I actually though by deleting the object of the class the two QLabels would be deleted too. But apparently that's not the case. Having added this in the destructor

~Item(){delete myName; delete myIcon;}

~Item(){delete myName; delete myIcon;}

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it works.

Seems very dirty for me

[jpn]

Those widgets are not children of the layout. Widgets added to a layout become children of the widget where the layout is installed on. This is why the widgets didn't get deleted still if the layout was deleted.

[grosem]

Those widgets are not children of the layout. Widgets added to a layout become children of the widget where the layout is installed on. This is why the widgets didn't get deleted still if the layout was deleted.

Aaah... I was not aware of this. Thank you

[grosem]

Ok, now the removing of QLayouts works. Unfortunatly I can't add new QLayouts to the QGridLayout at runtime. If I want to add them in the constructor of my QMainWindow it's no problem. But adding them later does not work properly. So the QGridLayout receives the new Layout but does not display it.
I read the Qt-list archive, where someone suggested to call activate on the QGridLayout, but this does not work - not a surprise as this suggestion is from 1998...

Any ideas?

EDIT: update() does not change anything

[jpn]

It should work. Did you, by any chance, forget to show() the widgets added at runtime?

[grosem]

It should work. Did you, by any chance, forget to show() the widgets added at runtime?

I do the same as I did in the constructor of QMainWindow (where the Items are shown). If I did not have to call show() there explicitly I don't have to do it somewhere else, have I?

The Items I add are looking like that


QHBoxLayout->QFrame->QLabel and QLabel;

If I call show on QFrame it opens seperatly new windows. show() at the QLabels has no effect.