Question

I have a QHBoxLayout which I add widgets to, one by one.
I alternate by adding a Custom Widget, than a QLabel (repeating).
The QHBoxLayout is owned by a QGroupBox.

However, I notice that the spacing between the Custom Widget and the QLabel is ‘irregular’ when there are few widgets added to the Layout.

I intend for the QLabels to be centered in the gap between the custom widgets, but the QLabels only approach the centre as more widgets are added.

These screenshots show the two cases.
The desired case (only occuring with lots of widgets in the layout),
and the undesired case (occuring when little widgets are in the layout).

As you can see in the bottom case, the QLabels are not centered between the Custom Widgets. Instead, they are very far to the right!

What is causing this behaviour??

I believe the QGroupBox has a centered (horizontal) alignment and the QLabels have a fixed width of 10 (or 20 for the ‘->’ QLabel) pixels (to avoid ugly overlap).

Any help at all would be greatly appreciated!
Thanks!

Specs:
python 2.7.1
PyQt4
Windows 7

The instantiation of the QHBoxLayout is absolutely normal and similiar to all examples.
Here is the code for the filling of the layout.

for i in range (0,len(Reactants)):

    self.WidgetHouse.Reaction_Element_Layout.addWidget(eval('self.OverallContainer_Reactants.Reactant_'+str(i)))

    # self.WidgetHouse.Reaction_Element_Layout           is the QHBoxLayout
    # self.OverallContainer_Reactants.Reactant_'+str(i)       is a Custom Widget

    if i != (len(Reactants)-1):
        tmp = QtGui.QLabel('+')
        tmp.setFixedWidth(10)
        tmp.setAlignment(QtCore.Qt.AlignCenter)
        self.WidgetHouse.Reaction_Element_Layout.addWidget(tmp)

    else:
        tmp = QtGui.QLabel('->')
        tmp.setFixedWidth(20)
        tmp.setAlignment(QtCore.Qt.AlignCenter)
        self.WidgetHouse.Reaction_Element_Layout.addWidget(tmp)

EDIT:

Setting a fixed width of the QLabels (tmp.setFixedWidth(10)) is the source of the ‘right anchoring’.
However, not setting a fixed width results in the same space being dedicated to QLabels and Custom Widgets in the layout, leading to an overlap of QLabels and Custom Widgets.

Identical to the code above, discluding ‘tmp.setFixedWidt(10)’

What can I do to prevent this that’s not completely horrible?
Can I move the Labels ‘back’ from the front?
(Calling .raise_() on all the custom widgets after everything was added to the layout did not work)

(Or will I have to do something like manually calculate the appropriate width of the labels based off the amount of widgets in the layout? Yuck!)

ANOTHER EDIT:

Progress:

I do not change the maximum/minimum (or fixed) width of the QLabels, but I do set their alignment to center.
Instead, I set a minimum width of the custom widget.
This fixes the apparent ‘overlapping’ (which wasn’t really the case) and makes the Labels appear ‘more centered’.

However, as you can see, the QLabels still aren’t perfectly centered – too far right.
If I don’t set a center alignment on the QLabels they are too far left.

What could be the problem now??

(I do not set a maximum width on the labels)

Thanks for all the help so far guys!

Answer 1

Solution to all problems:

Give the custom widgets a fixed width.

Results in perfectly centered, not ‘overlapping’ widgets.
🙂

Thanks for all the help guys!