I plan to use a spacer in my toolbar (below) between the 'Pause' and 'Settings' buttons to make the 'Settings' button right-aligned within the QToolBar. The separator below isn't cutting it.
The following method apparently works, although I haven't actually tried it yet:
QWidget* spacer = new QWidget();
spacer->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
// toolBar is a pointer to an existing toolbar
toolBar->addWidget(spacer);
toolBar->addAction("Right-aligned button");
(thanks to http://www.ffuts.org/blog/right-aligning-a-button-in-a-qtoolbar/)
Qt Designer doesn't seem to allow adding widgets to a QToolBar, although QToolBar does have an addWidget() method, as used above. So if I want to be able to add the spacer to my toolbar using Qt Designer (with a plugin, not promotion), should I subclass QAction, QWidget, or QWidgetAction? Is there even a way to write custom action plugins for Qt Designer?
You cannot subclass QAction and expect to use it gracefully in Qt Creator/Designer. It uses the tags in the ui and to add them to menus and toolbars. You can't specify a class="customclass" element along with a entry like other widgets. Because actions are treated differently, you cant even subclass them so that's out.
As for QWidgetAction/QWidget, you are in the same boat as QActionGroup, if you know what I mean.
(I personally think this is a big overlook in the design of the form designer!) So previewing that in the designer is also out.
The last thing you could do (invisible option 3) is QToolbar subclassing, but alas you can subclass it, but still, you wont be seeing anything in the desinger other than what a plain old QToolbar can do. That doesnt mean that it is completely out which is the point I'm coming to:
The real answer would have to be invisible option 4, subclassing QToolbar as a designer plugin (which would require a lot of coding on your part if you dont already know of one that is out there, I dont know of any that actually have designer plug-ins) Form Designer plugins are more not than often, but you could find someone's subclassed toolbar, and make it into a plugin yourself saving you a step (qt creator even has a template for that), then use it in qt designer and your set.
I know this question got asked 2 years ago but when I see an unanswered question, I think of those searchers that might read and get frustrated by a dead-end so if I can contribute I do... I hope I did at least help you or anyone else get on the right track, and good luck to you all!
Related
I don't know much about QT. I am trying to do my first GUI and actually this is the first thing that I want to do.
How can I set up top menu bar to switch between layouts? Again, I don't know yet how to even set up these layouts and I don't know the jargon to name the things theirs names, but I'll get to it.. I hope.
Actually, Windows has this type of windows all over the system. Can I make one of these myself?
Qt has a QtabWidget that has its own layout on every tab, so you dont need to define anything, qt handle t runtime the display of the layout associated to every tab
I have found a really neat custom widget for Qt and managed to incorporate it into Qt Designer. I would now like to create a customer widget in designer by placing 32 of these LEDs into a new widget in Designer, then add some functions to it such as giving it address and passing data into it that will then illuminate patterns in colours according to the passed data.
My questions are:
Can I do this? I have placed 32 LEDs on to a new QFrame widget in designer and named the LEDs 0-31, but am at a loss as to know what to do next.
Is there a tutorial anywhere for this? I have found loads of hits on google for creating custom widgets for designer, but not using designer.
Please bear in mind I am not a good Qt programmer, I write embedded code for micros in C and am really not good at object orientated code; I can just hack together relatively simple programs for test and measurement. I need something that will hand hold me through this.
http://doc.qt.io/qt-5/qtdesigner-worldtimeclockplugin-example.html
This seemed to be the kind of thing I wanted, it seemed to look like someone has placed widgets on a screen to create a new widget, but it seems to keep referring back to Creator.
Maybe I am trying to do something impossible. Maybe I have to place this new LED in creator with code?
Many thanks for any pointers.
Yes, it is. A Designer plugin basically consists of 2 Parts:
The Widget that you want to add to the designer
The plugin itself that provides information about the widget usw.
You can simply create the widget with the designer, add the QDESIGNER_WIDGET_EXPORT macro and thats it. Create your designer plugin to load this widget and it should work.
Note: Since you mentioned your not very experienced, you should try to follow the Custom Widget Plugin Example. Once you understood that one, it's only a small step to your designed plugin.
I'm comfortable with C++ but brand new to Qt. I apologize for my ignorance as I'm sure this is a very simple question. I'd like to make a custom clickable widget, basically a push button that is just a black square with Qt designer, but don't have any idea on where to start.
EDIT: after fumbling around I think I'm an epsilon closer.
I created a black_box.png file. In the resource browser I created a new resource and prefix, and added the black_box.png. Any advice from here?
You have a few options for what you want to achieve.
You can use custom painting to draw a new button that subclasses QPushButton, this is reasonably involved and provides a huge amount of flexibility to build it to your requirements.
You can use Qt's stylesheets mechanism to style it, you can get more information on it here: http://doc.qt.io/qt-5/stylesheet.html
Or you can set a QPixmap of your image to be a button icon, and size your button to match it, there's a good answer on how to do this on this question: How to set image on QPushButton?
When it comes to designing a GUI in Qt, I am hesitating between using the designer in Qt Creator, or doing everything in source code. I'm using Qt widgets and not QML.
If I use the designer I can easily create a GUI using qt standard widgets. But as soon as I need to subclass a widget to extend its functionality I have to build a Designer plugin to support my new widget. Is that correct? Or is there another way to it?
You can build all the GUI in Designer including custom widgets, and you can also build your custom widgets in Designer.
Designer does not need to interpret your custom widgets. Just use the promote functionality. With promote, you start with a plain widget within Designer and then tell the "real" class of it (your custom one) and the header file where it is decleared. The only drawback is that within Designer, it will stay looking like an empty widget.
In my experience, it is much better to use Designer for the GUI than writing source code yourself. You can easily change all the properties afterwards etc., and it is helpful even if you rely on custom widgets. Source code is not a good declarative language for GUI objects, with all the properties etc. Also you cannot play around, you would need to compile all the time just to tell "Is it better to have this text label in bold font?".
Sometimes I edit the XML files that are created by Designer by hand. For example, if I want to put a widget somewhere else in the object tree. If you don't mess up the XML, Designer will still read it and not destroy your changes. The only reason I see for writing GUI in source code is when you have repetitive elements, or dynamic changes based on data input, e.g. a for()-loop that produces elements. In my project I have some Selector Boxes that are filled with options in the source code.
And btw: If you prefer to write your GUI in code instead of using Designer, maybe you are not the right person to craft the GUI. Most programmers don't understand that while they are technically able to design a GUI, they are not always also competent in doing it.
http://hallofshame.gp.co.at/index.php?file=shame.htm&mode=original
It is a bit of a shortcut, but I often use a simple QWidget as a container for my custom widget. This way, I can setup sizing policies, put the whole thing in the layout I want before my custom widget is even in. Then, in C++, I add the custom widget as a child of the container widget.
edit: As ypnos mentioned you can promote the placeholder directly. You can find guidelines here
I want to use a custom widget in the GUI-Designer of Qt-Creator IDE.
So i created a class which inherits from Qt's QWidget. It worked to place
it on a QMainWindow programaticaly, but have to do my work in the desiger
where it does not appear as an option in the kist of components.
I googled to find a solution for problem an found an manual on, who guesses, the
Qt doc page ( https://doc.qt.io/archives/qt-4.7/designer-creating-custom-widgets.html
and https://doc.qt.io/archives/qt-4.7/designer-creating-custom-widgets.html).
I tried to follow it but doesn't work.
Does someone know an other way to do this or can give a hint where i can search
for problems following this tutorial?
Thanks in advance.
Codierknecht
There is a different example in the examples section of the Qt documentation that I think is a lot clearer.
Custom Widget Plugin Example
It was a little unclear to me when reading the tutorial where the Q_EXPORT_PLUGIN2() macro goes, but having full example code and project alleviates that.
If you are like me, the analog clock example didn't do it for you, in which case I found just one better tutorial. It may be on the kde site but I you dont need kde to do it, it just explains how to make the custom widget a plugin so you can add it into Qt Designer, rather than having to code it in, which is the norm when you just add a widget to your project and customize the class. I hope this page helps you like it helped me, get in the right direction of writing a single Qt Designer (or multiple) plugin:
Writing Qt Designer Plugins
If this link ever becomes dead, just do a search for the link itself, usually that will turn up the original page in someone's cache, as they do in the other examples above (the dead links in the above answers that just take you to main area and not to the pages originally intended).