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

[_-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)

[Christian Ehrlicher]

@_-mohamed-_ said in how to open a file in my qt app via double clicking on it:

i printed the URL and i got (C:\Users\moham\OneDrive\Desktop????.txt) as i said in the previous post

You must not print non-ascii characters on a windows console - windows is too stupid for this. You QMessageBox or similar.

[_-mohamed-_]

@Christian-Ehrlicher I have set the text in QTextEdit using ui->TextEdit->setPlainText (URL)

[JonB]

@_-mohamed-_
I said:

Look at file.errorString() when the file.open() fails.

[_-mohamed-_]

@JonB why? I said that file.open() fail because the path is incorrect

ok now I tried file.errorString() and it returns The filename, directory name, or volume label syntax is incorrect.

[_-mohamed-_]

I tried to open the same file with all text editors on my computer like (notepad++, VScode, Pycharm, Qt creator...) And they all opened the file successfully, is the problem in Qt?

[_-mohamed-_]

I got a new problem when i override dropEvent function in QTextEdit
I used event->mimedata()->urls->at (0) to get the url of the droped file

But i got the same problem which is in arabic letters files name i got questions marks instade of the real file name(?????)

[JonB]

@_-mohamed-_
How do you know that? @Christian-Ehrlicher wrote earlier

You must not print non-ascii characters on a windows console - windows is too stupid for this. You QMessageBox or similar.

Did you act on that? It is not clear to me how you are outputting this string, have you looked at it on a QMessageBox or a QLabel, or have you used the debugger to check what the actual bytes are in the string?