Qt application is not loading your custom resources from resources.qrc

panyilun3

Hello Qt Community,

I'm new to Qt and working on a small game in Qt6 (C++). I'm trying to use the resources.qrc to load icon(a Window Icon and a Icon on button), but only the built-in Qt resources are available. My custom images (flag.png, minesweeper.png) are not loading.

Project Setup

Qt Version: 6.8.1
OS: Ubuntu Linux
Build System: CMake
IDE: CLion

Project structure

Minesweeper/
│── main.cpp
│── minesweeper.cpp
│── minesweeper.h
│── cellbutton.cpp
│── cellbutton.h
│── resources.qrc
│── icons/
│   ├── flag.png
│   ├── minesweeper.png
│── CMakeLists.txt

resources.qrc

<RCC>
    <qresource prefix="/">
        <file>icons/flag.png</file>
        <file>icons/minesweeper.png</file>
    </qresource>
</RCC>

CMakeLists.txt

cmake_minimum_required(VERSION 3.30)
project(Minesweeper)

set(CMAKE_PREFIX_PATH "/home/panyilun/Qt/6.8.1/gcc_64/lib/cmake/Qt6")
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)
set(CMAKE_AUTOUIC ON)

find_package(Qt6 COMPONENTS Core Gui Widgets REQUIRED)

qt_add_resources(Minesweeper "resources.qrc")

add_executable(Minesweeper main.cpp resources.cpp minesweeper.cpp cellbutton.cpp)

target_link_libraries(Minesweeper Qt::Core Qt::Gui Qt::Widgets)

main.cpp

#include <QApplication>
#include "minesweeper.h"
#include <QDirIterator>
#include <QDebug>

void listQtResources() {
    QDirIterator it(":", QDirIterator::Subdirectories);
    while (it.hasNext())
        qDebug() << it.next();
}

int main(int argc, char* argv[]) {
    QApplication app(argc, argv);
    Minesweeper window;
    window.setWindowIcon(QIcon(":/icons/minesweeper.png"));
    window.setWindowTitle("Minesweeper");
    window.show();
    return app.exec();
}

minesweeper.cpp

void Minesweeper::toggleFlag(int row, int col) {
    auto& cell = grid[row][col];
    auto* button = buttons[row * COLS + col];

    QIcon flagIcon(":/icons/flag.png");

    if (!cell.isFlagged && !cell.isQuestioned) {
        cell.isFlagged = true;
        cell.isQuestioned = false;
        button->setText("");
        button->setIcon(flagIcon);
    } else if (cell.isFlagged) {
        cell.isFlagged = false;
        cell.isQuestioned = true;
        button->setIcon(QIcon());
        button->setText("?");
    } else if (cell.isQuestioned) {
        cell.isFlagged = false;
        cell.isQuestioned = false;
        button->setIcon(QIcon());
        button->setText("");
    }
}

Any help would be greatly appreciated!

OwerPlay

While this does not answer your question there is an alternative to .qrc files:
using qt_add_resources like this:

qt_add_resources(Minesweeper "resources"
        PREFIX "/" FILES
        icons/flag.png
        icons/minesweeper.png
)

Other option is mentioned here:
"if you have set(CMAKE_AUTORCC ON) then there's no need to call qt5_add_resources just add your .qrc files to the list of sources for the target as they were .cpp files"
https://forum.qt.io/post/468643 by @VRonin

Christian Ehrlicher

@panyilun3 said in Qt application is not loading your custom resources from resources.qrc:

QIcon flagIcon(":/icons/flag.png");

It has to be QIcon flagIcon(":/flag.png");

We need to fix https://doc.qt.io/qt-6/resources.html#qt-resource-collection-file-qrc though... :(

panyilun3

@OwerPlay Thank you for you help! Indeed, adding resources.qrc directly to executable fixed the bug.
For ppl having same issue, may also reference doc below.
https://doc.qt.io/qt-6/resources.html#qt-resource-collection-file-qrc

panyilun3

@Christian-Ehrlicher Thanks Christian!