Getting an image from mysql database (as BLOB field) through subclassed QSqlQueryMode

[anda_skoa]

Couple of things:

- in order to be able to use this class as a QQuickImageProvider, it needs to have a "is-a" relation ship, i.e. publically inherit from QQuickImageProvider
- in data() it doesn't make sense to use the role as given to query the base class, after all these roles will most often be your custom roles and have no meaning for the base class
- you are missing the roleNames() override that returns the mapping of role names (used in QML) to role numbers (using in the C++ API).

Cheers,
_

[MarkoSan]

Couple of things:

- in order to be able to use this class as a QQuickImageProvider, it needs to have a "is-a" relation ship, i.e. publically inherit from QQuickImageProvider
- in data() it doesn't make sense to use the role as given to query the base class, after all these roles will most often be your custom roles and have no meaning for the base class
- you are missing the roleNames() override that returns the mapping of role names (used in QML) to role numbers (using in the C++ API).

Cheers,
_

Well, class is publicly inherited from QQuickImageProvider:

class UePeopleModel : public QSqlQueryModel, QQuickImageProvider

class UePeopleModel : public QSqlQueryModel, QQuickImageProvider

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I've upgraded function data(), is now ok:

QVariant UePeopleModel::data(const QModelIndex &index,
                             int role) const
{
    QVariant value=QSqlQueryModel::data(index,
                                        role);
    if(value.isValid())
    {
        switch(role)
        {
            case ueRoleName:
            {
                return value.toString();
            }   // case
 
            case ueRoleImage:
            {
                return QString::number(index.row());
            }   // case
 
            default:
                value=QVariant();
        }   // switch
    }   // if
 
    return value;
}   // data

QVariant UePeopleModel::data(const QModelIndex &index,
                             int role) const
{
    QVariant value=QSqlQueryModel::data(index,
                                        role);
    if(value.isValid())
    {
        switch(role)
        {
            case ueRoleName:
            {
                return value.toString();
            }   // case

            case ueRoleImage:
            {
                return QString::number(index.row());
            }   // case

            default:
                value=QVariant();
        }   // switch
    }   // if

    return value;
}   // data

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But what do I have to put inside method UePeopleModel::image?

Sincerely yours,
Marko

[anda_skoa]

Well, class is publicly inherited from QQuickImageProvider:

class UePeopleModel : public QSqlQueryModel, QQuickImageProvider

class UePeopleModel : public QSqlQueryModel, QQuickImageProvider

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Nope. Unless your code looks different in reality, this is a private inheritance

I've upgraded function data(), is now ok:

Nope, see my last comment.

But what do I have to put inside method UePeopleModel::image?

You get the BLOB from the base class for the given row and then load it into a QImage.
If the BLOB is data in a format known to Qt, then you can probably use QImage::loadFromData().

Cheers,
_