Moving widgets within a layout.

[importantman]

I am using QVBoxLayout to have a vertical list of custom composite widgets which contain an up and down button, so to move that widget up and down within the list.

It doesn't work.

Do I have to delete and then recreate the widget in order to move it ?

I have tried using layout->remove() and layout->insert() but it doesn't appear to be working.

[wysota]

I think using QLayout::takeAt() and QBoxLayout::insertWidget() should work.

[importantman]

Wow ! Fast reply !

IIRC takeAt() is only in qt4, and so far I'm using qt3.

[wysota]

Oh, sorry for that. In your case use QBoxLayout::insertWidget() and QLayout::remove().

[importantman]

Just did that, and I am using ::findWidget(*QWidget) to get the widget index number, and it works at first, then it goes haywire.

I have 3 sample widgets included, like this:

startPosition.png
and I can move number 2 up to the top by pushing the up button, like this:

firstClick.png
but if I try to move number 1 back to the top, I get no response. If I push the up button a second time, it doesn't move. In fact, if a push the up buttons a few times, none of them respond.

I have not implemented the other buttons yet.

Here is the relevant code (it is declared as a slot in the header). PositionElementLine inherits QWidget.

void PositionElementBox::up(PositionElementLine *line)
{
        int index = boxLayout->findWidget( line );
 
        if(index > 0 )  //an index of 0 means the widget is at the top !!
        {
                boxLayout->remove(lineList.at(index));
                boxLayout->insertWidget( ( index - 1 ), line );
        }
}

void PositionElementBox::up(PositionElementLine *line)
{
        int index = boxLayout->findWidget( line );

        if(index > 0 )  //an index of 0 means the widget is at the top !!
        {
                boxLayout->remove(lineList.at(index));
                boxLayout->insertWidget( ( index - 1 ), line );
        }
}

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[importantman]

oops! The error is in line 7. the lineList is copied from old code. should be

->remove(line);

[wysota]

Why not implement it as QTable and QTableItems and simply forget about the problem?