[SOLVED] QList<customObcject> saved with QSettings

Michal

There is similar topic on the forum LINK but the guy found out different solution.

Im trying to save data using QSettings QList<recipe>. I've read that I need to use Q_DECLARE_METATYPE( Type) I deleted unnecesary data.
Here is my recipe.h

class recipe
{
public:
    recipe();
    recipe(const recipe &obj);
    ~recipe();
};
// 1) Q_DECLARE_METATYPE(recipe)

//recipe.cpp
#include "recipe.h"
recipe::recipe()
{
}

recipe::recipe( const recipe &obj)
{
}

recipe::~recipe()
{
}

When I uncomment 1) I have an error: D:\Projects\FoodBook\recipe.cpp:3: error: expected constructor, destructor, or type conversion before 'Q_DECLARE_METATYPE'
Q_DECLARE_METATYPE(recipe).

What is it that I do wrong? or how would any of you save List of custom class objects to be loaded at startup??

Thanks for your support.

Charlie_Hdz

Well, First at all, Q_DECLARE_METATYPE is about the MetaObject System of Qt,this mean that your object "recipe" must be a QObject to work.

Chris Kawa

@Charlie_Hdz No, it doesn't have to be a QObject.
@Michal You don't seem to include <QMetaType> in your header. That's probably it.

KiwiJeff

This works for me:

#ifndef RECIPE_H
#define RECIPE_H

#include <QMetaType>

class recipe
{
public:
    recipe();
    recipe(const recipe &obj);
    ~recipe();
};

Q_DECLARE_METATYPE(recipe)

#endif // RECIPE_H

Michal

Of course! didn't know macros need includes...thanks!

recipe newRecipe;
newRecipe.setName("NotConverted");
qDebug() << "BeforeConvName: " << newRecipe.Name();

QVariant variant = QVariant::fromValue(newRecipe);
    if(variant.canConvert<recipe>())
    {
        qDebug() << "Can Convert";
        recipe anotherNewRecipe = variant.value<recipe>();
        qDebug()<<"AfterConvName:"<<anotherNewRecipe.Name();
    }

anotherNewRecipe's name shows result: "" . Why?

And by the way, another question:
Why does the customObject (in this case recipe) can't be created dynamically?
If I do so, there is an error and It will not go through.

Some help under the LINK regarding MetaType.

Chris Kawa

@Michal said:

Why?

Because your copy constructor does not copy anything?

If I do so, there is an error and It will not go through

What does the error say?

Michal

error: invalid application of 'sizeof' to incomplete type 'QStaticAssertFailure<false>' enum {Q_STATIC_ASSERT_PRIVATE_JOIN(q_static_assert_result, __COUNTER__) = sizeof(QStaticAssertFailure<!!(Condition)>)}

I have just read that: Values of a registered type can be constructed dynamically via QMetaType::construct()
There is an example in the link above. Thanks for your help! I will figure it out, still missing pure c++ knowledge ;)