Qt qrc resource file - can't load icon - c++

I have a Qt5 desktop project and I added a "resource.qrc" file with the Qt Creator editor which created the following line into the project's .pro file:
RESOURCES = resource.qrc
I put a blank prefix and a png file (14x14) and I tried to use it like this:
QPixmap pixmap = QPixmap ("://my_image.png");
ui->combobox->addItem(QIcon(pixmap), "itemname");
The problem is: the icon won't show up!
The following works:
QPixmap pixmap(14,14);
pixmap.fill(QColor("red"));
ui->combobox->addItem(QIcon(pixmap), "itemname");
so the problem must be in the resource embedding process.. I noticed that the generated "exe" hasn't a resource section inside it... I don't have static linked external libraries, so I don't think I need the Q_INIT_RESOURCE(resource) macro (it gives me undefined external)
Update:
I'm posting here my qrc file:
<RCC>
<qresource prefix="/">
<file>my_image.png</file>
</qresource>
</RCC>
it's pretty simple and I don't understand why at runtime icons are not showing up

I had this same issue recently, where I malformed the resource string. If you are using a current version of Qt Creator, you can open your .qrc file for edit and then right-click the resource (in this case image) that you are trying to address, then click "Copy Resource Path to Clipboard". And voila, you have the correct resource string every time.
Qt Creator is awesome.
Hope this helps!

#Nikos C. gives you useful advice, but I think your main problem was that you didn't use the correct link to the resource.
In your code, you have:
QPixmap pixmap = QPixmap ("://my_image.png");
but, according to the documentation, it should be
QPixmap pixmap = QPixmap (":/my_image.png");
or you can give aliases to your resources, and use those instead.

Issue is solved is use rcc.exe
C:\root\QT>c:\root\QT\4.7.4\bin\rcc.exe Headless.qrc -o qtresources.cpp
During compilation you should have images in the path.
Create the qtresources.cpp file include this file in makefile or project. You should able to see the image.

Related

How to include an icon in the title bar of window in Qt?

I want to be able to replace the existing standard icon with my own but I am unsure how to do so. I only started Qt one week ago so I don't know much about the application. In addition to this I looked at the Qt website but their method for adding an icon did not work on my computer.
Besides using a RC file (Windows) you may specify the icon directly using qmake.
win32: RC_ICONS = icon.ico
Make sure it detects the path correctly. In the provided case the icon resides in the project root directory right beside the project file.
For window icons you typically, if application wide applicable, use some method of QApplication.
...
QApplication app(argc, argv);
...
app.setWindowIcon(QIcon(":/icon");
...
which is consuming the resource file using the alias icon. Here is an example (res.qrc):
<RCC>
<qresource prefix="/">
<file alias="icon">icon.png</file>
</qresource>
</RCC>
More information on resources are here.
Perhaps try the function setWindowIcon function on the QWidget or QApplication.

QT Resource File - Images Not Showing When Running

I just upgraded to QT Creator 5.3 and created a brand new QT Widgets Application project and am using the Microsoft VC++ compiler. All I have is a resource file with "logo.png" added (which opens in QT if I double click it), and a label that I am trying to set the background image for. The problem is that no matter what I do I cannot get the image to show up when the program is running. The only way I can get it to show the image is by not using the resource file and instead map directly to the file (ex. "c:/blah/blah/logo.png")
Also, if I set the background image in the UI designer, the background shows up in the IDE but NOT when I run the program. I have tried probably 20+ variations of the code, including resource file aliases as well as adding the files to the project directly, and nothing seems to work.
I'm not sure if there is a step I am missing, or if perhaps there is something that I have to do to get the project to compile the image.
Resources.qrc
<RCC>
<qresource prefix="/">
<file>logo.png</file>
</qresource>
</RCC>
loginform.cpp
QPixmap pixmap = QPixmap (":/logo.png");
ui->label->setPixmap( QPixmap(pixmap));
Project.pro
OTHER_FILES += \
logo.png
RESOURCES += \
Resources.qrc
After countless hours of trial, error, and mostly frustration, I have been able to resolve this issue by simply running qmake.
To do this I just right clicked on the project and clicked "Run qmake" and suddenly the image errors (as well as a few others) were resolved!

Error trying to load qml from resource

I did an app loading qml from local filesystem, and it was working fine, but now I'm trying to change it to load from qml, but it never find my file.
I've looked into the web and tried some solutions, nothing worked.
My qml file is in a subdirectory of the project qml/MyProject/main.qml
Then I created a resource file and added a prefix "/" (tried with different names too), and then added my qml file to it.
Then I changed the generated qtquick2applicationviewer.cpp setMainQmlFile to: http://pastebin.com/kRJDJACW
Then I tried the following lines to load the qml from resource:
viewer.setMainQmlFile("qrc:/main.qml");
viewer.setMainQmlFile("qrc://main.qml");
viewer.setMainQmlFile("qrc:/other_prefix/main.qml");
viewer.setMainQmlFile("qrc:/qml/MyProject/main.qml");
viewer.setMainQmlFile("qrc://qml/MyProject/main.qml");
My resource file: http://pastebin.com/1sjUqk2T
Qt version: 5.2/ QtCreator 3.0
What am I doing wong?
The code you are showing looks alright, at least the following line:
viewer.setMainQmlFile("qrc:/main.qml");
The error is likely somewhere else. You have not shared the project file of yours, but the reason is probably that you do not have this file correctly in your resource.
You would need to use the following entry in your qmake file:
RESOURCES = main.qrc
Solved, thanks guys. For some reason my resource file was in "other files", not in "resources" area of Qt Creator, so I added a new one and it worked. Thanks!

Adding files to Qrc ressources

I have added a jpg file to the QRC ressources to not drag everytime the full path of the image file.
However, it's not displayed when I am starting the user interface where it's supposed to be loaded!!
I added to it an alias. It's not working. But when I write the name of the file included in the project solution, it's well displayed.
PS: I want to organize my project and put the file in QRC ressources
This is how did I do:
QPixmap img(":/projet/image.jpg"); // It's not loaded
QPixmap img("image.jpg"); // It's OK
Please check your .qrc file first.
You can check your file with another editor like notepad++, vim , joe etc.
Does it look similar to this example:
<RCC>
<qresource prefix="/project">
<file>FOLDER/image.jpg</file>
</qresource>
</RCC>
If it does you can access your image through:
QPixmap example(":/project/FOLDER/image.jpg");
Good luck!

Qt: Path to file in QString

I have problem with storing a path to file in Windows in a QString. I'm using Qt with C++.
QString resourcePath = ":/images/frog.bmp";
if( ! QFile::exists(resourcePath) )
{
qDebug("*** Error - Resource path not found : %s", resourcePath.data());
}
This code results with this:
*** Error - Resource path not found : :
So I can see that resourcePath.data()) contains just ":". I assumed that the problem is with slashes, so I tried changing "/" with "\" but the result is the same.
But if I write:
QString resourcePath = "C:\\Users\\Boris\\Desktop\\Frogger3\\images\\frog.bmp";
everything works just fine. What am I missing? Is there a reason why colon cant be the first sign in QString? How should I write path to the file in the same folder as the code?
Thanks in advance!
The style of resource path you are using is implying that the file frog.bmp is in a resource file. So either you need to resolve the path of the bmp file at run-time, or you need to add a resource file to your project.
If you use the UI designer the concept of resource files is handled automatically, but if you want to access resources through code there are a few things you need to do.
First create a resource file. In visual studios (with the visual studios add-in) there is a wizard to do this. Essentially it is just an xml file with the extension .qrc looking something like this:
<RCC>
<qresource prefix="/images">
<file>frogger.bmp</file>
</qresource>
</RCC>
Now this file has to be processed during the build. If you have used .ui files, it is similar. There is a tool called "rcc.exe" that takes the qrc file as an input and generates a .cpp file that needs to be compiled and linked with your project.
If you are using visual studios and have the Qt Visual Studios Plugin, this should all be handled for you when you add the qrc file to the project.
If you are using QMake then your pri file should contain a "RESOURCES" section where you need to list your qrc file something like:
RESOURCES += yourqrcfile.qrc
Now, once that is done. You can access your resources in code. Your call to QFile::exists should resolve the file name.
In the case where you put your resources in a static or shared library, you will need to add the following line to your class to ensure that the resource file is loaded.
Q_INIT_RESOURCE(yourqrcfile); // do not include the extension, just the name of the file.
Here are a few links that explain things in more detail:
Creating a resource file in Qt Creator
Explaining how resource files work