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.
Related
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.
So I currently have got a custom widget, and I want to add them to the main window after clicking a button. I would like to add them all to one fixed position first and then I will be able to drag them wherever I like. I am able to create and display these custom widgets with help of QHBoxLayout or QVBoxLayout, but in this case they will not be in the same position after I create them. Any help will be appreciated!
As the names suggest, the QLayout classes manage the position and geometry of the items added to them. You cannot move (eg. drag) an item out of a layout w/out first removing it from the layout (QLayout::removeItem() and derivatives). For example when you drag a toolbar or dock widget out of a QMainWindow it goes through all sorts of machinations to remove it from the MW layout, change the widget's window flags, remember the old position in the layout, and so on. And the reverse to dock it again.
To do what you describe (drag widgets arbitrarily around a window) you would need to not use a QLayout and position the widgets manually by specifying a QWidget::setGeometry() for example. After initial position, and assuming the user has some way to grab the widget (title bar or drag handle you made, etc), you'll probably still need to manage their positions, for example if the main window is resized (if you care about keeping them contained). Essentially you'd have a bunch of separate widgets acting as individual windows and probably need some way to keep track of them.
I don't know what kind of widgets you're talking about, but one option may be a QMdiArea which lets the user drag windowed widgets around, tabify them, save/restore state, and so on.
For more flexibility you could also look into the Qt Graphics Framework. The graphics scene has a lot of features for user-movable items/widgets, keeping track of them, and so on. It is probably the most flexible method overall, and you can also use regular QWidgets inside a graphics scene.
A couple other Q/A about arbitrarily positioning widgets (I'm sure there are more to be found):
QPushButton alignment on top another widget
How to keep Push Buttons constant in relative to change of Label Size in PyQt4
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've inherited my class from QWidget. Basically no extra code, just changes with the editor.
The way I use it:
focusWidget = new FocusWidget(this); //this points to the mainWindow
focusWidget->show();
focusWidget->hide();
Now the widget appears like this (it now looks ugly because of the bad 4k scaling), at the top left corner of the mainWindow.
I intend to use my application mostly full screen.
Is this usage correct?
How can I make it a floating widget?
If I want multiple widgets like that, how can I control their position?
I am using Qlabels to plot some graphs and images (via setpixmap).
My basic layout is:
QVBoxlayout main layout via qdialog's setlayout.
QHboxlayout (array of QLabels)
Qlabel expandedPlot (optional expanded plot of one of the above QLabels)
QLabel mainImage Main image display
Within the QDialogs re-implemented keypress event handler, I hide()/show() the expanded plot. When I hide() the expandedPlot, the layoutmanager recovers about 1/2 of the vertical usage. Then when I drag the window, the layout manager recovers the remainder of the vertical space (as if there was no item present).
How can I force the behavior of moving the window? I want the layout manager to completely recover the vertical space.
I am using Qt 5.6 on windows, but want cross-platform solutions.
Thank you, mike
Because laying out the widget is quite expensive, Qt doesn't always do it. If you change the size of enclosed widgets you are likely to need to call updateGeometry on them to trigger the enclosed layout manager to re-layout. But if you hide the widget, updateGeometry does nothing. In that case you need to call adjustSize on the parent widget, which will then trigger the re-layout.