[SOLVED]can't open file from qresources

[A Former User]

The file works for me. Please try this in your load_object() function:

    QFile file(":/plane/j3pipercub.obj");
    if (!file.open(QIODevice::ReadOnly|QIODevice::Text)) {
        qDebug() << "file read error";
        return;
    }
    const QByteArray ba = file.readAll();
    file.close();
    const QString s( ba );
    qDebug() << s;

[A Former User]

Ok, let's see if we can copy the file's content to another file:

    QFile file(":/plane/j3pipercub.obj");
    if (!file.open(QIODevice::ReadOnly|QIODevice::Text)) {
        qDebug() << "file read error";
        return;
    }
    const QByteArray ba = file.readAll();
    file.close();

    QFile file2("/home/pw/piper.obj"); // +++++ ADJUST PATH ++++++
    if (!file2.open(QIODevice::WriteOnly)) {
        qDebug() << "file write error";
        return;
    }
    qDebug() << file2.write(ba);
    file2.close();

[mcosta]

HI,

have you used Q_INIT_RESOURCE to initialize the resource??

[Hamed]

No! where should I initialize it?

[mcosta]

Hi,

in the main(); something like

int main (int argc, char *argv[])
{
    QApplication app(argc, argv);

    Q_INIT_RESOURCE(mresources);

    .....
}

[A Former User]

@mcosta said:

Q_INIT_RESOURCE

Since when is this needed? Works for me without this.

[Hamed]

dear @mcosta it's not helped

[mcosta]

@Wieland Q_INIT_RESOURCE is needed if the resource is not embedded in the application or on some platform

Normally, when resources are built as part of the application, the resources are loaded automatically at startup. The Q_INIT_RESOURCE() macro is necessary on some platforms for resources stored in a static library.

[A Former User]

@mcosta Things are a bit strange here. Reading from the resource works. In the code I posted above there is the bytearray ba and it has the correct size, but it contains only null bytes. But only on Hamed's computer! Works on mine. I don't get it.

[mcosta]

hi,

so you could try to use an alias

<RCC>
<qresource prefix="/plane">
<file alias="j3pipercub.obj">j3pipercub.obj</file>
</qresource>
</RCC>

[Hamed]

It didn't help either!

[A Former User]

@mcosta Ok, the code that copies the content from file to file2 works. The new file on the filesystem has the correct content. So the bytearray is not full of zeros. But output via qDebug() doesn't work. The system's locale is English so this should work.

[Ebrahim Karimi]

I'm Using Qt 6.5.2 and had the same issue and after an hour of digging and testing all your solutions i did some digging on the build folder and i saw this:

in <QBuild_Dir>/<cmake_project_name>/<module_name>_qml_module_dir_map.qrc

<RCC>
  <qresource prefix="/">
    <file alias="/<<<cmake_project_name>>>"><<<QBuild_Dir>>>/<<<cmake_project_name>>></file>

  </qresource>
</RCC>

so there is an alias for the resource!

to use the resource on my C++ code i had to add it to the beginning of the resource path like

before:
":/assets/img.svg"
 after
":/<cmake_project_name>/assets/img.svg

and it works 👌