Save model to file

[matulik]

Hello.
I have a problem. I want to save a QStandardItemModel objects into file.
But... how?

Have you got any simple idea?

[Lykurg]

Loop through your data and save it to a file. But how do you have created your model (on what is it based?)?

[victor.fernandez]

You should walk through the model and save on an item-by-item basis. You may open a file and use QDataStream to save the contents of each item. For example, assuming the model is a table model (for simplicity):

void loadModel(QIODevice *device, QStandardItemModel *model)
{
    QDataStream stream(device);
    int rowCount, columnCount;
    stream >> rowCount;
    stream >> columnCount;
 
    for(int row = 0; row < rowCount; row++)
        for(int column = 0; column < columnCount; column++) {
            QString item;
            stream >> item;
            model->setItem(row, column, item);
        }
}
 
void saveModel(QIODevice *device, QStandardItemModel *model)
{
    QDataStream stream(device);
    int rowCount = model->rowCount();
    int columnCount = model->columnCount();
    stream << rowCount;
    stream << columnCount;
 
    for(int row = 0; row < rowCount; row++)
        for(int column = 0; column < columnCount; column++) {
            stream << model->item(row, column)->text();
        }
}
 
...
 
QStandardItemModel myModel;
/* populate the model */
 
QFile file;
if(file.open(QIODevice::WriteOnly))
    saveModel(&file, &myModel);

void loadModel(QIODevice *device, QStandardItemModel *model)
{
    QDataStream stream(device);
    int rowCount, columnCount;
    stream >> rowCount;
    stream >> columnCount;

    for(int row = 0; row < rowCount; row++)
        for(int column = 0; column < columnCount; column++) {
            QString item;
            stream >> item;
            model->setItem(row, column, item);
        }
}

void saveModel(QIODevice *device, QStandardItemModel *model)
{
    QDataStream stream(device);
    int rowCount = model->rowCount();
    int columnCount = model->columnCount();
    stream << rowCount;
    stream << columnCount;

    for(int row = 0; row < rowCount; row++)
        for(int column = 0; column < columnCount; column++) {
            stream << model->item(row, column)->text();
        }
}

...

QStandardItemModel myModel;
/* populate the model */

QFile file;
if(file.open(QIODevice::WriteOnly))
    saveModel(&file, &myModel);

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[SykeS]

I know that there is something like QStandardItem::write, but I have no idea how to use it.

[squidge]

QStandardItem::write only writes the data and flags of the item to a selected QDataStream, it doesn't deal with any child elements. Victor's solution looks better for that task.