I'm trying out qt creator lately and i hate reading hours of docs and tutorials just for doing simple tasks.
So, in winforms i can drag & drop a control from toolbox and set the dock property so it automatically maximizes itself to it's container's size.
What is the equivalent of this behaviour in qt?
I googled this and found it strange that nobody wondered the same before.
There are differences between the concepts of WinForms and Qt. You need to study the concept of layouts. Take a look at the relevant part of the documentation of Qt Designer: Using Layouts in Qt Designer
Before a form can be used, the objects on the form need to be placed
into layouts. This ensures that the objects will be displayed properly
when the form is previewed or used in an application. Placing objects
in a layout also ensures that they will be resized correctly when the
form is resized.
Qt uses layouts. Add QHBoxLayout or QVBoxLayout to the parent widget.
Related
I'm pretty new to Qt, and I can't find an answer to very basic question:
is it possible to use conditions when using the ui designer?
for example, that if a var x is set to true widget 1 will be displayed, otherwise widget b will be displayed in the same area?
I know how to do it in the code but wondered if it possible using the design tool...
In my experience there is not a way to do it using the designer in a QWidgets application, though I have to admit I never really tried to do that. In a Qt Quick QML application you can probably use a binding on the visible property to hide/show the desired item.
The Qt desktop application I am required to develop has the following GUI:
The application window is split into 3 parts -
left-side window - has a stack of clickable menu items one below the other. Clicking on each item will show up the corresponding UI elements on the prominent right-side window which is much bigger.
right-side window - contains UI to display some data depending on which menu item is clicked on the left-side window. Each left-side window menu item has a different corresponding right-side window UI.
top (header) window - contains some company "brand" related graphics and also a panel to select a serial port from a list along with graphics to represent connect/disconnect status.
How do I develop this kind of UI? What Qt classes should I be using? I'm a beginner to Qt and would deeply appreciate any help. Thank you.
I'd suggest starting in Qt Designer or Qt Creator to create your UI by dragging and dropping different kinds of objects. Qt Designer is a standalone form designer where Qt Creator is full development environment that also includes the functionality of Qt Designer. Using the form designer is a lot easier, particularly when starting out, than creating widgets programmatically.
There's multiple ways to do the list of items on the left. You can use a QListWidget or a series of individual QPushButton instances, one per option. If the list of items changes, then managing the QListWidget content is going to be easier than instantiating a QPushButton for each item, but you might like the appearance of the QPushButton better. It just depends on what you want.
For the right side, look into QStackedWidget. It's specifically designed to display a stack of content where only one item is available at a time.
For the top panel, again, use the form designer to create the layout. You can store an image in a QLabel. A QComboBox might be what you want for the list, or again, you may want a QListWidget. It just depends on what appearance and user experience you're looking for. For the connect/disconnect status, you can use a QLabel and change out the graphics as the status changes.
You'll need to learn about slots and signals; those are crucial to anything Qt-related.
I would like to know if anybody knows if it is possible to drag a QDockWidget from one window to another.
I am developping an application that has a lot of windows. Each of these windows has a specific usage. I want to use QDockWidget because of the automatic rescaling when docking a widget in the main window. But I would also like to have the possibility to have a new dock area in a new window so that I can put together all the widgets related one to each other.
Does anyone have a suggestion?
As far as I know, you cannot drag a QDockWidget from one application to another if they are developed separately.
On the other hand, I think that you can reparent a QDockWidget to another QMainWindow, only if it's part of the same application.
...aaaaand you can always try to intercept the drap/drop events and pass information between the two windows with a protocol of your own: define a new mime type for the drag and define the syntax of the data associated to the QDockWidget. Then, implement the code to analyze the data and reconstruct the contents of the QDockWidget in the target window... not an easy task!
I am trying to implement a custom OpenGL scene (wrapped in a QGLWidget), but still use QT controls (such as slide bars and buttons). I tried to make my main widget a QGLWidget, which has QWidgets as children. The child widgets seem to work (when I click a pulldown menu, its options appear), but the widget fails to draw (I see a white square). I changed the base class of my children widgets from QWidget to QGLWidget, and now QPainter calls work, but QT GUI stuff is still not displaying...
Some claim that a QGLWidget can not have QWidgets as children... I am not sure about that and I'm not willing to give up. By the way, I am using Visualization Library to draw the OpenGL scene, but it is just an OpenGL wrapper...
Any clues where the problem might be? Also, key events stop being processed for some reason when I add subwidgets to the GQLWidget.
Update:
I tried various combinations of widgets and layouts. It seems that the QGLWidget just gets drawn on top of anything. I even tried with raise() to arrange Z-depth of the widgets, to no avail. Is overlayGL() the only way to draw on top of an OpenGL widget?
Update 2
After months of trying, I figured out it is something related to QT. Whenever a QGLWidget is drawn on top of another QGLWidget, the first's background() function is not called. So a button is there and can be clicked, but it's not drawn. My workaround was to draw everything myself using QPainter - that works. What I found curious is, one has to use QPainter::startNativePainting() in order to draw with it. One would expect that they would overload start() in QPainter to call startNativePainting() whenever a QGLWidget is the painting device...
Another (maybe useful) fact is that QPainter calls CHANGE the Opengl context. So if you have another tool in cooperation with QPainter (in my case Visualization Library), chances are that one of them will crash (in my case VL which checks if the context state has been cleared before each frame).
There is a labs example of rendering Qt widgets using opengl it's a little old and I haven't tried it with the improved qglwidget in 4.8
There is also an issue with drawing over the top of a fullscreen QGLwidget - it was supposedly a bug in NVidia's openGL driver. It doesn't seem to have been resolved
https://bugreports.qt-project.org/browse/QTBUG-7556
If I were you I would use the QGLWidget as a viewport for a QGraphicsScene, then you can draw your widgets using a QGraphicsProxyWidget. That way you get a proper OpenGL viewport with the ability to put widgets in and manipulate them easily.
Did u try to call update() explicitly? I find that sometimes QGLWidget update the display stuff kind of slow.
This is an old question, but I recently had quite a bit of trouble with this, and this is what helped me -
Use QML/QT Quick. QML is a javascript-like language that allows you to layout your widget elements on a window and do basic processing on events like mouse clicks. There are a few other cool features, but the one that is most relevant to this question is that you can import qt widgets from C++ code.
So you can make a custom QGLWidget, import it into the QML window, and set the size/position/stick widgets on top of it in whatever you want, very easily. QT's Scenegraph example does a great job explaining this. Scenegraph's code is also included as an example in at least Qt Creator 3.2.1 Open Source (that's the version I have anyway)
I'm learning Qt independently, and this may seem like an easy question (because it is). I primarily come from a Swing background, so the concepts are very similar.
My question:
I am using Qt Designer to create a QTreeView item in the UI Designer. How do I do something as simple as setting the model of the TreeView?
Usually I would do something like:
QTreeView *tree = new QTreeView();
tree->setModel( &myModel);
I don't even know how to get a reference to the QTreeView object that the UI Designer created. Any direction will be appreciated!
Depending on your version of Qt, your main window will either include as a member or privately inherit a class with all of your designer widgets. So, within MainWindow, e.g. either my_widget->show(); or ui->my_widget->show(); to show the widget, respectively.
In your case, my_tree_view->setModel(my_model);