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I have a Qt dialog application. Now I dont want that dialog to be resizeable. I am not sure how to achieve this. I tried a bunch of things but still when the dialog launches this dialog can be resized.

What is the property that i should set to disable the dialog/Widget resize.

I also tried


But i get an error saying..

source\nimcac_settingsMain.cpp(36) : error C2248:
**'QSizePolicy::QSizePolicy' : cannot access private member declared in class 'QSizePolicy'**
kernel\qsizepolicy.h(177) : see declaration of 'QSizePolicy::QSizePolicy'
kernel\qsizepolicy.h(34) : see declaration of 'QSizePolicy'

Kindly help me out with this.

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9 Answers 9

up vote 30 down vote accepted

I don't know if you already tried it, but QWidget::setFixedSize should do what you want

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The compile error you get is because you try to pass a QSizePolicy::Policy to setSizePolicy(QSizePolicy), but there's no implicit conversion from QSizePolicy::Policy (which is the policy for one dimension) to QSizePolicy (which is a class containing, among other things, one Policy per dimension (height, width)). QSizePolicy doesn't work on top-level widgets (windows) anyway, though.

setFixedSize() only works if you know the size of the dialog in advance (and usually you don't, what with changing font sizes and languages). You can do

window()->setFixedSize( window->sizeHint() );

but it's much better to use

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

That lets the layout determine the size of the dialog, but doesn't allow resizing, which I assume is what you were asking for.

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Or simply this->setFixedSize(this->size()); –  Daniel Saner Jan 24 '13 at 15:54
Or even simpler :) setFixedSize(size()); –  lapis Aug 15 '13 at 16:13

You need to change the windowFlags of the dialog and set it to Qt::MSWindowsFixedSizeDialogHint.

This only works in windows.

For more information please see this example: http://doc.trolltech.com/4.5/widgets-windowflags.html

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If you use QtCreator (of course you are) you can set the property HorizontalsizePolicy to fixed and Vertical Policy also to Fixed. Then you can set the maximumSize to the dimensions you want. The window will not maximise again.

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In code you can do something like this,

Dialog->resize(581, 292);
QSizePolicy sizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
Dialog->setMinimumSize(QSize(581, 292));
Dialog->setMaximumSize(QSize(581, 292));

In QtCreator do as follows,

  1. Select the dialog box widget
  2. Locate the dialog box widget in Object Window
  3. In Object Window, right click on dialog box object to popup a menu
  4. Select "Size Constraints" -> "Set Maximum Size" from the menu
  5. Right click again on dialog object to popup a menu
  6. Select "Size Constraints" -> "Set Minimum Size"
  7. In Property Window,
    • ensure "sizePolicy"->"Horizontal Policy" has value "Fixed"
    • ensure "sizePolicy"->"Vertical Policy" has value "Fixed"
    • ensure "sizeGripEnabled" is not checked
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In case you are designing UI in QML and launching using QDeclarativeView, try the below code.

QScopedPointer<QmlApplicationViewer> viewer(QmlApplicationViewer::create());
//To make the window non-resizable

Here QmlApplicationViewer is derived from QDeclarativeView.

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From the Qt documentation, setSizePolicy() method either takes zero argument or two arguments but cannot be one argument. That's why you get this compilation error. From my experiment, if you don't set the fixed size. This method has no use. The window can still be resizable.

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On QT Creator, in the UI editor, click on the top object in the properties window, then scroll at the bottom in the Layout part. You should see the layoutSizeConstraint property.

Set the layoutSizeConstraint to SetFixedSize.

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