QList wrapper

firen

Hi,

I would like to override QList.

If I instantiate it for example with QString, I would write:

QList<QString>

and if I would like to use Pointer it would be

QList<QString*>.

So is there a chance that I could override QList, that an instantiation QList<QString> would work like QList<QString*>? I would ALWAYS like to store/work only with the pointers.

Thanks!

Christian Ehrlicher

@firen said in QList wrapper:

So is there a chance that I could override QList, that an instantiation QList<QString> would work like QList<QString*>? I would ALWAYS like to store/work only with the pointers.

No, and why do you need to store a pointer to a QString in a container? Happy memleaks...

mpergand

@firen
A template class ?

template <class T>
class PointerList : public QList<T*>
{
    public:
               PointerList() : QList<T*>() {}
               ~PointerList()
                    {
                    qDeleteAll(this->begin(),this->end());
                    }

    private:
             Q_DISABLE_COPY(PointerList)

};

firen

@mpergand That was my idea as well but didn*t work. maybe I did something wrong. I will try again. :-)

I read about Q_DISABLE_COPY. Isn`t it mainly for QObject based types?

Christian Ehrlicher

@firen said in QList wrapper:

I read about Q_DISABLE_COPY. Isn`t it mainly for QObject based types?

If you want to copy PointerList <T> then you have to provide a proper copy operator, the one generated by the compiler will not work, therefore Q_DISABLE_COPY.

mpergand

@firen said in QList wrapper:

That was my idea as well but didn*t work. maybe I did something wrong. I will try again. :-)

Show your code.
You must add dynamically allocated objects to the list, it seems obvious but maybe it needs to be said.

firen

It looks like this now:

template <class T>
class CPtrListWrapper:
  public QList<T*>
{

  using Item = T*;

public:
  CPtrListWrapper():
    QList(),
    m_bAutoDelete(false),
    m_pCurrentItem(nullptr)
  {
    
  }
   
  ~CPtrListWrapper()
  {

  }

//I need to wrap an old Containerclass and want to replace it internally by QList and these is one of the original methods
  void insert(uint i,
    const T* d) // 
  {
    QList::insert(i, d);
  }

But this gives me an error C2664 if I try:

bas::qtw::CPtrList<QString> m_q5List;
const QString* pString = new QString("TEST");

m_q5List.insert(0, pString);

The error is that he cannot convert "const QString *" in "QString *const &"

jsulm

@firen said in QList wrapper:

But this gives me an error C2664 if I try:

Please post the whole error, not just its id.
Also, show the declaration of m_q5List.

firen

@jsulm I have edited the post.

Thanks! :)

JonB

This post is deleted!

firen

This post is deleted!

firen

This post is deleted!

mpergand

    PointerList<QString> plist;
    plist.append(new QString("World"));
    plist.insert(0,new QString("Hello"));

    for(const QString* str : plist)
        qDebug()<<*str;

print:
"Hello"
"World"