how to open a file in my qt app via double clicking on it

[SGaist]

Can you try again using QCommandLineParser ?

[_-mohamed-_]

@SGaist how can i use QCommandLineParser to get application's arguments

[eyllanesc]

@_-mohamed-_ See the official example: https://doc.qt.io/qt-5/qcommandlineparser.html#details

[_-mohamed-_]

@eyllanesc
@SGaist
i cant get application's arguments using QCommandLineParser

[eyllanesc]

@_-mohamed-_ Basic rule of the forum: Without code we cannot help you. Show the code where you implement the logic with QCommandLineParser, so we can analyze where the error is and so we can probably give you a solution.

[_-mohamed-_]

@eyllanesc I just don't know how to do that

I tried

QCommandLineParser command;

   QStringList arguments = command.positionalArguments();
   if(arguments.count() > 1)
   {

       QFile file(arguments.at(1));

       if(!file.open(QFile::ReadOnly | QFile::Text))
           QMessageBox::information(this, "can't open file", "can't open the specified file");

       else
       {
           QTextStream text(&file);
           text.setCodec("UTF-8");
           QString fileContents = text.readAll();
           ui->TextEdit->setPlainText(fileContents);
           file.close();

           edited = false;
           url = arguments.at(1);
           changeTitle();
       }
   }

[eyllanesc]

@_-mohamed-_ Your sentence: i cant get application's arguments using QCommandLineParser is confusing. You should have said I don't know how to implement, why don't you use the official example? Try it and when it fails, they receive goods with the code that does not work.

[_-mohamed-_]

@eyllanesc
when i use args like qDebug() << args.at(0); i got this The program has unexpectedly finished.

[eyllanesc]

@_-mohamed-_ what is args?, please provide a minimal and verifiable example.

[_-mohamed-_]

@eyllanesc it is from the official example

const QStringList args = parser.positionalArguments();
   // source is args.at(0), destination is args.at(1)

you can find it here:

int main(int argc, char *argv[])
{
    QCoreApplication app(argc, argv);
    QCoreApplication::setApplicationName("my-copy-program");
    QCoreApplication::setApplicationVersion("1.0");

    QCommandLineParser parser;
    parser.setApplicationDescription("Test helper");
    parser.addHelpOption();
    parser.addVersionOption();
    parser.addPositionalArgument("source", QCoreApplication::translate("main", "Source file to copy."));
    parser.addPositionalArgument("destination", QCoreApplication::translate("main", "Destination directory."));

    // A boolean option with a single name (-p)
    QCommandLineOption showProgressOption("p", QCoreApplication::translate("main", "Show progress during copy"));
    parser.addOption(showProgressOption);

    // A boolean option with multiple names (-f, --force)
    QCommandLineOption forceOption(QStringList() << "f" << "force",
            QCoreApplication::translate("main", "Overwrite existing files."));
    parser.addOption(forceOption);

    // An option with a value
    QCommandLineOption targetDirectoryOption(QStringList() << "t" << "target-directory",
            QCoreApplication::translate("main", "Copy all source files into <directory>."),
            QCoreApplication::translate("main", "directory"));
    parser.addOption(targetDirectoryOption);

    // Process the actual command line arguments given by the user
    parser.process(app);

    const QStringList args = parser.positionalArguments();
    // source is args.at(0), destination is args.at(1)

    bool showProgress = parser.isSet(showProgressOption);
    bool force = parser.isSet(forceOption);
    QString targetDir = parser.value(targetDirectoryOption);
    // ...
}

[eyllanesc]

@_-mohamed-_ How have you run your executable? You must run: your_executable input_filename output_filename.

[_-mohamed-_]

@eyllanesc
I run the app from qt creator

but the first argument should be the exe file path and it does not need second argument.
It should work when i call the first argument

[eyllanesc]

@_-mohamed-_ No, precisely QCommandLineParser considers that it is not necessary and only obtains the arguments, not the name of the program. If you want to know the name of the executable then use QFileInfo(QCoreApplication::applicationFilePath()).fileName().

The format is:

executable arg1 arg2 ... argN

The executable name is not a program argument for QCommandLineParser.

[_-mohamed-_]

@eyllanesc oh,
I thought it was likeQCoreApplication::arguments()

I need the second argument which is the path of the file I want to open

[eyllanesc]

@_-mohamed-_ If you want to pass arguments using Qt Creator then click on the "Projects" on the left side and press the "Run" button, then put the arguments in "Command Line Arguments"

[_-mohamed-_]

@eyllanesc oh thanks this information will help me and save my time.

I tried to get the argument using QCommandLineParser, I got the same result
(C:\Users\moham\OneDrive\Desktop\????.txt)

note: when I open the same file using windows notepad it workes fine.

this is main.cpp:

#include "mainwindow.h"
#include <QApplication>
#include <QDebug>
using namespace std;

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

    QCommandLineParser parser;
    parser.process(a);

    QStringList args = parser.positionalArguments();

    MainWindow w;
    w.settext(args.at(0));

    w.show();
    return a.exec();
}

and this is settext() function from mainwindow.cpp:

void MainWindow::settext(QString URL)
{
    QStringList arguments = QCoreApplication::arguments();
    if(arguments.count() > 1)
    {

        QFile file(URL);

        if(!file.open(QFile::ReadOnly | QFile::Text))
            QMessageBox::information(this, "can't open file", "can't open the specified file");

        else
        {
            QTextStream text(&file);
            text.setCodec("UTF-8");
            QString fileContents = text.readAll();
            ui->TextEdit->setPlainText(fileContents);
            file.close();

            edited = false;
            url = URL;
            changeTitle();
        }
    }
}

when i double click the text file i got error(QMessageBox::information(this, "can't open file", "can't open the specified file");)

[JonB]

@_-mohamed-_
So why not debug out URL and the file path from QFile file for yourself? Do you mean that filename really has ???? in it??

[_-mohamed-_]

@JonB no the real file name is "عربي.txt" but i can't get the real name from app's argument

[JonB]

@_-mohamed-_
Look at file.errorString() when the file.open() fails. And print out URL and file.fileName().

[_-mohamed-_]

@JonB i printed the URL and i got (C:\Users\moham\OneDrive\Desktop????.txt) as i said in the previous post
So file.open () can't open a strange text (????.txt)