[Solved]Writing to file doesn't work.

Darkmalex

Hi, for my QML project I need a simple IODevice to work with files so I took "this one from Nokia Dev":http://developer.nokia.com/community/wiki/Reading_and_writing_files_in_QML
But I tweaked it a little, for purposes of my work.
Reading from file works like a charm(this proves, that there is no "wrong path to file" problem"), but writing to file is broken, and I can't find a reason why.

Here is the code:

fileio.h

@#ifndef FILEIO_H
#define FILEIO_H

#include <QObject>

class FileIO : public QObject
{
Q_OBJECT

public:
explicit FileIO(QObject *parent = 0);

Q_INVOKABLE QString read(const QString& Url);
Q_INVOKABLE bool write(const QString& Url, QString data);

public slots:

signals:
void error(const QString& msg);

private:
QString mSource;
};

#endif // FILEIO_H
@

fileio.cpp

@#include "fileio.h"
#include <QFile>
#include <QTextStream>

FileIO::FileIO(QObject *parent) :
QObject(parent)
{

}

QString FileIO::read(const QString& Url)
{
mSource = Url;
if (mSource.isEmpty()){
emit error("source is empty");
return QString();
}

QFile file&#40;mSource&#41;;
QString fileContent;
if ( file.open(QIODevice::ReadOnly&#41; ) {
    QString line;
    QTextStream t( &file );
    t.setCodec("UTF-8");
    do {
        line = t.readLine();
        fileContent += line;
     } while (!line.isNull());

    file.close();
} else {
    emit error("Unable to open the file");
    return QString();
}



return fileContent;

}

bool FileIO::write(const QString& Url, QString data)
{
mSource = Url;
if (mSource.isEmpty()){
emit error("source is empty");
return false;}

    QFile file&#40;mSource&#41;;
    if (!file.open(QIODevice::WriteOnly | QIODevice::Truncate&#41;){
        emit error("Error");
        return false;}

    QTextStream out(&file);
    out << data;
    //emit error("data:" + data); //This one was used to debug, Yet no errors were emmited when Write is called


    file.close();

    return true;

}@

Thanks, in advance.

dheerendra

I dont' see issue with code. What is the data written ? what is broken here ? What is the data you are dumping from QML ? Also can you give sample of how you are calling read and write from QML ?

Darkmalex

I needed my app to load settings from external file (I cant use QSettings, as I wish to give user access these settings by external script or through text editor when app is not launched). So for every setting I have a file with a single Utf-8 string, which is loaded into qml (smth like @property string interfacecolor1 : myFile.read("://settings/color1");@), and it works.
But I also want to change settings in qml

Example would be:

@TextField{
id:fieldsurname
Layout.fillWidth: true
text: myFile.read("://settings/surname"); //Shows user current setting, works perfectly
onTextChanged: {console.log(fieldsurname.text); //I just check if textfield behaves as supposed, returns what I expect from it.
myFile.write("://settings/surname", fieldsurname.text); //Write text from textfield (it will be for an embeded platform, so I probably need to change setting every new char)
surname = myFile.read("://settings/surname"); //I write new setting to property from new text from file
console.log(myFile.read("://settings/surname")) //Returns an unchanged string
}
}@

Also forgot to mention, that manualy editing files also works, settings are changed accordingly, app behaves as it should

Darkmalex

For future reference, I found that qrc files are readonly. So fixed.

ambershark

Well, first off you can lose the QIODevice::Truncate from your open in write since it is implied by QIODevice::WriteOnly.

Secondly, you may be having a trouble because you are using a binary file with a text stream.

Try doing this:

@
QFile file(mSource);
if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
return false;

QTextStream out(&file);
out << data << endl;

file.close();
@