I'm subclassing from QDockWidget and I want my class to use form. I've made a form based on QWidget and included Ui class in my QDockWidget-based class. But the build result differs from the Qt Designer preview, because QDockWidget completely ignores all the preset size policies and layouts from the form, so most of the content just doesn't show up and the rest has nothing in common with the preset settings. My class looks fine if I subclass from QMainWindow or QWidget. How to use forms for QDockWidget?
This question could do with some sample code from the .ui files to clarify the question.
However one possible cause of this is that Qt form layouts QFormLayout by default don't expand to fill their parent widget. If the QFormLayout is embedded another top level layout such as a grid layout the contents of the QFormLayout will then expand to fill the available space.
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I have a QMainWindow with the widgets laid out in a grid. They all resize proportionally when the window resizes as expected, except for the widgets placed inside a QGroupBox. The QGroupBox itself resizes, but the widgets inside just stay on the same place. If I apply a lay out on the QGroupBox, the widgets loose their original positions. Note that I'm using the .ui file with PyQt4. You can get the file here.
And this is what happens:
From Qt documentation on QGroupBox:
QGroupBox doesn't automatically lay out the child widgets (which are
often QCheckBoxes or QRadioButtons but can be any widgets).
There is an example showing how to setup a layout for a QGroupBox (which is the same a setting up a layout for any QWidget based object meant to store other objects, like QFrame for instance).
You must create a layout, call QGroupBox::setLayout and then add widgets to the layout. If you use QtCreator, right-click the QGroupBox and select the layout you want to use for it from the context menu.
I'm a bit new to QT but have to work on existing code. Here's the case:
I have a class extending QDialog. the constructor sets a QGridLayout then adding three other widgets to it. One of the widgets is a QScrollArea containing a QGroupBox. this QGroupBox has a QVBoxLayout and there I'm adding a list of widgets at runtime. The size of the scroll area should grow until a given limit is reached before showing the scrollbars so that they are only used when the dialog would grow too high. I've found that the sizeHint of the outer layout doesn't update when the sizeHint of the scroll area updates. How can I refresh this, or is there a better way to resize the parent dialog?
What about using widgetResizable property of QScrollArea? It should try to resize view to avoid using scorllbars.
I have a Rectangle widget, and a resize box widget, and a text edit widget. How can I compose them without using layouts ? I want all of them as a single widget.
The documentation for how to do a manual layout is in Qt Layout Management here.
Are you sure you can't use one of the standard layouts? You can make a custom widget with three children positioned inside using a layout (or layouts) and your new custom widget will still be just a single widget.
I would like to know the Java panel equivalent in QT. I mean which class do we need to use in QT, i.e. qframe or qwidget. I need to add many panels to my QT mainwindow.
QFrame, QScrollArea, etc. have properties that handle panel appearance and are suitable for component containers and form layout.
QWidget has no frameShape(), frameShadow(), or lineWidth(), but it has layout and size operation methods, so it can also be used as a panel if you do not need borders, scroll, docking or other additional behavior.
Several examples on trolltech use QWidget rather than a QMainWindow as the main window for simple Qt applications.
Now I need just a simple window with a single content widget (QGlWidget) that covers the entire client area.
However, when I show a QWidget window with a single content window it automatically resizes itself to be tiny.
If I create the QWidget parent window without a child It is a nice large default size.
I don't want to resort to using Layouts for a single child window :/
What I understand is that you use a QWidget to display your QGIWidget. Try calling the show method of your QGIWidget directly (if your QGIWidget class inherits QWidget), Qt will create the window decoration for you.
Otherwise if you really need your widget to be inside one another, and fit its size, you'll have to use a layout.
Either follow gregseth's advice or you can simply resize the widget yourself.
(though this way you'll loose nice auto-resizing which is provided by Qt when you use layouts)
In your case you can basically do something like:
QGlWidget* myWidget = new QGlWidget;
myWidget->resize(QApplication::desktopWidget()->availableGeometry().size());
// or maybe instead of resizing show it in fullscreen:
myWidget->showFullScreen();
(actually I don't remember if showFullScreen() will do resizing for you, maybe you'll need both resize+showFullScreen :))
Cheers :)
P.S. Using layout is actually an option. It's not expensive and it's flexible. All it gets: "layout = new QVBoxLayout(myWidget); layout->addWidget(myWidget);" and you're done :)
Not always.
I've found that a QMainWindow will not work as the parent widget when using the QVBoxLayout and QHBoxLayout to arrange child widgets.
If you create a QWidget and use that in place of the QMainWindow then the layouts will work correctly.
QWidget* centralWidget = new QWidget( MainWindow );
MainWindow->setCentralWidget( centralWidget );
If you use QtCreator and look at the code it creates you can see it creating a 'hidden' widget if you try to use the layouts directly at the top level.
It's not obvious, intuitive, or documented anywhere that I've found.