I want to make a widget in Qt and customize it.for example change the background and use my own one.change the shape of the buttons and animate them and the style of starting of the page and some other things that usually are using in professional softwares.is there any reference and document to learn these works?please help me....thank you
Qt Style Sheet is probably what you are looking for, check the docs and syntax . By the way, QML is considered more flexible, when it comes to GUI
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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've been struggling with learning how to use stylesheets to customize the look of my widgets in Qt.
For example, after much effort, I just figured out that the name of the property that determines what color the text on a QComboBox drop-down menu is when it is mouse-over'd is selection-color, and the background color is selection-background-color. But most of that I discovered by random guess-and-check.
Where can I find documentation that will actually tell me these things so I don't have to guess? Does Qt follow some sort of standard naming convention?
http://doc.qt.nokia.com/latest/stylesheet-reference.html
http://doc.qt.io/qt-5/stylesheet-examples.html
The above link gives examples for pretty much every control. For the combobox it mentions the QAbstractItemView, and mentions that you need selection-background-color etc... to style it - with an example.
It doesn't always explain what each property does however, which is where the doc that baysmith linked to comes in.
So with these two documents together you should be in good shape.
I wanted to consult with the sages here regarding Qt and skinning, get your opinion and chart a path for my development. My requirements are as follows:
My Qt/C++ application (cross platform with Mac, Windows and Linux versions) needs to have modular skins.
A skin is defined as a set of one or more elements: - Window background texture - Look/feel of UI controls such as edit boxes, drop down, radio buttons, buttons etc. - Look/feel of window "caption", resize grips etc.
Skins will be installed with the application installer, allowing the user to choose which one he/she wants to use. Users should be able to change skins on the fly.
Can I go the QML route? should this be custom and based on simple resources which are built into the application? Any design advice will be appreciated.
Thanks.
If I understood you correctly then stylesheet is the best way forward. You can create stylesheets similar to CSS and then pass them as command line option to your application or load on invocation to style your application at runtime. That way you can create multiple stylesheets each having a different look and feel and allow user to load them at will. Since its CSS it doesn't need any new learning and you can keep all your styling outside your source code.
Here are a list of resources that can get you up and running quickly:
http://blog.qt.io/blog/2007/11/27/theming-qt-for-fun-and-profit/
http://doc.qt.io/qt-5/stylesheet.html
I haven't played with QML yet, but you could also create a custom QStyle implementation that supports your resource format. Note that you'd lose style sheet support if you went this route.
Changing window captions is a little trickier if you want portability.
QML, if I understand correctly, doesn't really skin the widgets, it mainly deals with GUI layout etc etc.
QStyle is used to change the looks. It is a bit low-level though, and requires programming, so if you want to load different user-created skins (from an XML or so) it might be tricky to support extensive skinning. Chaining colors and a few items are easy enough though. (There might be someone else who've done something you could re-use.. not sure.)
For modifying widgets, use QStyle::polish(). You could use that to change the background picture (if it's a top-level window, or of a certain class). There are numerous repaint method to change almost every part of every widget.
Store/load the style using QSettings, by reading and setting the desired Style just after QApplication but before your main window is constructed.
I'm new with Qt and am looking for advice on how to structure this.
I want a flexible widget that can display a set of images (normally read from a directory but other sources too) and let the user select images with the arrow keys and/or mouse and also apply custom tags.
For example there might be 5 tags defined by the application. A user can press a key to select one, and then a little icon would appear in or near the image preview showing that it was selected for that tag.
Would I need to implement this from scratch via drawing on a QWidget or is there something that would make a sensible base class? Thanks!
I would use a QListView base class, and then subclass QStyledItemDelegate.
There is an example here which might help you.