Reading and writing files in QML (Qt)

Question

I am trying to implement Reading and writing files in QML and came across the linked article from Nokia but have not been able to successfully use the seemingly obvious code

Answer 1

A complete example of FileIO can be found on this page: https://qmlbook.github.io/ch17-extensions/extensions.html#fileio-implementation

class FileIO : public QObject {
    ...
    Q_PROPERTY(QUrl source READ source WRITE setSource NOTIFY sourceChanged)
    Q_PROPERTY(QString text READ text WRITE setText NOTIFY textChanged)
    ...
public:
    Q_INVOKABLE void read();
    Q_INVOKABLE void write();
    ...
}

We will leave out the properties, as they are simple setters and getters.

The read method opens a file in reading mode and reads the data using a text stream.

void FileIO::read()
{
    if(m_source.isEmpty()) {
        return;
    }
    QFile file(m_source.toLocalFile());
    if(!file.exists()) {
        qWarning() << "Does not exits: " << m_source.toLocalFile();
        return;
    }
    if(file.open(QIODevice::ReadOnly)) {
        QTextStream stream(&file);
        m_text = stream.readAll();
        emit textChanged(m_text);
    }
}

When the text is changed it is necessary to inform others about the change using emit textChanged(m_text). Otherwise, property binding will not work.

The write method does the same but opens the file in write mode and uses the stream to write the contents.

void FileIO::write()
{
    if(m_source.isEmpty()) {
        return;
    }
    QFile file(m_source.toLocalFile());
    if(file.open(QIODevice::WriteOnly)) {
        QTextStream stream(&file);
        stream << m_text;
    }
}

And source code can be found here: https://github.com/qmlbook/qmlbook/tree/master/docs/ch17-extensions/src/fileio