Save values to a config file

[Sucharek]

@JonB Well, I didn't do anything with preapptasks.h.
What do I add in there?

[JonB]

@Sucharek
@J.Hilk gave you the definitions of a couple of methods of a PreAppTasks class. So in C++ you know you will need to provide the necessary class declaration in the .h file. Which I think from your error messages you have not done.

[Sucharek]

@JonB Ok, so I added
copyIniToDestDir();
getDestIniFile();
to the .h file, but I'm not sure what to declare there (err message: C++ requires a type specifier for all declarations).
I'm also having a problem with declaring the File variable.
On
QFile *orgFile = new File(":/config/config.ini");
when I try to declare it in the .h file (QFile File;), it doesn't fix the error message (unknown type name 'File').

[JonB]

@Sucharek
At this point you need to learn some basic C++ if you expect to code with Qt. You cannot do so without knowing the language,

[Sucharek]

Hi, so I've looked into it, and fixed almost all errors, except the "unknown type name 'File'".
I still can't figure out how to fix that one.

[J.Hilk]

@Sucharek thats actually a typo, and I now see, thats actually from my original code, I blame auto correction:

QFile *orgFile = new File(":/config/config.ini");
QFile *orgFile = new QFile(":/config/config.ini");

[Sucharek]

Hi, ok, when I get home, I'll try it.

[JonB]

@Sucharek
I don't know whether the other C++ experts would concur (comments always welcome!), but if you are intending to put

QFile *orgFile = new QFile(":/config/config.ini");

in the class member variables declaration in the .h file, I wouldn't. I would suggest such an initialisation (i.e. the new ... part) belongs better in the class constructor.

[Sucharek]

@JonB
As long as it works, I'm good with it.

I also find interesting that in this part of the code:

if(orgFile){
        if(destFile && destFile->exists()){
            qDebug() << "exists";
        } else {

If i change the resource prefix, or the config.ini name, it will STILL print "exists".
I also have another question. How do I write and read the file, now that the code probably works?

[artwaw]

@Sucharek https://doc.qt.io/qt-5/qfile.html is what you need.

Please learn at least the absolute basics of C++ (and Qt while we're at it - both are very well documented), if your intention is to make it work by using the code snippets provided by the others you'll get nowhere in the long run.

[Sucharek]

Hi, so I've looked into it and I can read from the file, but can't write.
I've tried multiple methods, but they don't seem to work.
my .cpp file:

#include "preapptasks.h"
QFile *orgFile;

PreAppTasks::PreAppTasks()
{

}

QFile *PreAppTasks::getDestIniFile()
{
//in your case:
    return new QFile(QStandardPaths::writableLocation(QStandardPaths::AppDataLocation) + QString("/config/config.ini"));
}

void PreAppTasks::copyIniToDestDir()
{
    orgFile = new QFile(":/config/config.ini");
    QTextStream in(orgFile);
    QFile *destFile = getDestIniFile();
    //QFile *orgFile  = getOrgIniFile();
    //in your case simply:

    if(orgFile){
        if(destFile && destFile->exists()){
                orgFile->open(QIODevice::ReadOnly | QIODevice::Text);
                qDebug() << orgFile->isOpen();
                QString line = in.readLine();
                qDebug() << line;
                orgFile->close();

                orgFile->open(stdin, QIODevice::ReadWrite | QIODevice::Text);
                qDebug() << orgFile->isOpen();
                orgFile->write("a");
                line = in.readLine();
                qDebug() << line;
                orgFile->close();
        } else {
            //DestFile does not exist (propably the first program execution) -> simply copy from install folder
            //But first, create the folder, if it does not exist
            QFileInfo info(destFile->fileName());
            info.setFile(info.absolutePath());
            if(!info.exists()){
                QDir d;
                d.mkpath(info.absoluteFilePath());
            }
            orgFile->copy(destFile->fileName());
        }
    }

    if(destFile){
        destFile->deleteLater();
        destFile = nullptr;
    }
    if(orgFile){
        orgFile->deleteLater();
        orgFile = nullptr;
    }
}

So, in
if(destFile && destFile->exists()){ ... }
I tried to read the contents of the file (currently 50), which worked, but writing doesn't.
EDIT: Also, when I try to read the line on ReadOnly mode, it works, but in ReadWrite mode, it doesn't even print anything.

P. S.: I'm sorry that you have to deal with me, but I just want to get this to work.

[J.Hilk]

@Sucharek said in Save values to a config file:

I'm sorry that you have to deal with me, but I just want to get this to work.

Don't worry, we all started somewhere sometime.

And I brought this path up, so I'll see it finished :P

Give me a some time, I'll make an working example

[Sucharek]

@J-Hilk Thanks for the confidence boost :)

[J.Hilk]

@Sucharek
here ya go:

https://github.com/DeiVadder/PersistentConfigIni.git

Interestingly enough, I found a bug in my old code.
It wasn't necessary that I changed the config file so I never noticed. But one has to change the permission of the copied file to also be writeable. Since it's copied from a read only directory and that property carries over.

🤷‍♂️

[Sucharek]

Hi @J-Hilk, thank you so much for the example.
I've looked on your GitHub repos and I see that you have more examples I could use in the future.
Anyway thanks for making the example.