what to do to make windows non-resizable?

[jamadagni]

Please find a small project of mine attached. I would like to know what to do to make the window non-resizable. I tried setting the sizePolicy of the main window to Fixed,Fixed (in Designer) but it still is resizable. What am I missing? Thanks in advance.

[marcel]

In Ui.cpp, at the end of the constructor, put:

setFixedSize( sizeHint ()  );

setFixedSize( sizeHint ()  );

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Regards.

[wysota]

There is a better way:

layout()->setSizeConstraint(QLayout::SetFixedSize);

layout()->setSizeConstraint(QLayout::SetFixedSize);

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This way it'll adjust the size when the size hint changes.

[marcel]

It's the same:

QLayout::SetFixedSize
The main widget's size is set to sizeHint(); it cannot be resized at all.

Regards

[wysota]

It's not the same. When the size hint changes (for example becomes smaller) my code will resize the widget. Yours won't. One is dynamic, the other is static.

[marcel]

To Wysota:

Ok, you're right :

case SetFixedSize:
        // will trigger resize
        mw->setFixedSize(totalSizeHint());
        break;

case SetFixedSize:
        // will trigger resize
        mw->setFixedSize(totalSizeHint());
        break;

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( it's from qlayout.cpp , in function activate ).

But I believe both approaches will have the same effect on the attached dialog because from what I can see in the attachments, none of the widgets are resized dynamically, once the dialog is made visible.

[wysota]

But I believe both approaches will have the same effect on the attached dialog because from what I can see in the attachments, none of the widgets are resized dynamically, once the dialog is made visible.

What if the font or language changes?

[marcel]

OK, you got me

[jamadagni]

Thanks to all who replied.

I added:

layout() -> setSizeConstraint ( QLayout :: SetFixedSize ) ;

layout() -> setSizeConstraint ( QLayout :: SetFixedSize ) ;

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at line 40 of ui.cpp but now I get a very tiny window which shows nothing. I am now unable to resize the window which would be good except I can't see anything at all.

[jamadagni]

I also don't understand why setting the sizePolicy to Fixed isn't enough to do this.

[wysota]

I added:

layout() -> setSizeConstraint ( QLayout :: SetFixedSize ) ;

layout() -> setSizeConstraint ( QLayout :: SetFixedSize ) ;

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at line 40 of ui.cpp but now I get a very tiny window which shows nothing. I am now unable to resize the window which would be good except I can't see anything at all.

It probably means you didn't apply a layout to the form or somewhere lower in the hierarchy.

I also don't understand why setting the sizePolicy to Fixed isn't enough to do this.

Because sizePolicy only works for a widget that is inside a layout and obviously a top-level window (like yours) is not inside one.

[marcel]

Because your ui doesn't have a layout set.

I have attached the fixed version. Try it. Should work now...
I just set a vertical layout to your window.

Regards.

[jamadagni]

Thanks it works, but I still have a few questions:

1. I created the UI file using Designer. Is it a designer bug that it did not create a layout object?
   
   Should setSizePolicy(Fixed) not be enough to declare the window of fixed-size? After all that is the definition of Fixed:
   
   

   QSizePolicy Class Reference:
   
   QSizePolicy::Fixed : 0 : The QWidget::sizeHint() is the only acceptable alternative, so the widget can never grow or shrink (e.g. the vertical direction of a push button).

2. Why does Qt Designer not use this method itself?
   
3. Why does Qt Designer by default create a centralWidget(QWidget) and layoutWidget(QVBoxLayout)? What is their use?

[marcel]

1. No, it is not a bug. You should layout your widgets.
As Wysota pointed out, QMainWindow is not a regular widget. It does not have a parent widget, therefore no layout to manage it's size and position.

2. Not sure what you mean? Do you mean why there isn't an option to set the size constraint? Maybe because the designer doesn't know the actual (runtime) contents of the widgets and this would mix things up ( could give you a wrong preview of the dialog ).

3. Probably just for preview reasons. But that shouldn't make things worse for you. You can always break the layout and set another one.

Regards