Help with getting my custom model working

[thomaspu]

Thanks for the replies, cause I've really been struggling with this. I think I have reimplemented all needed functions. Here's whats in my header file so far and that I have defined in my source file.

ConnectionListModel(QObject *parent = 0);
    ~ConnectionListModel();
 
	 //Required items to make this model work
	 int rowCount(const QModelIndex &index = QModelIndex()) const;
	 QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
 
	 //required items to be able to edit items
	 bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole);
	 Qt::ItemFlags flags(const QModelIndex &index) const;
 
	 //Required to be able to resize the model (add & remove shit)
	 bool insertRows(int row, int count, const QModelIndex &parent = QModelIndex());
	 bool removeRows(int row, int count, const QModelIndex &parent = QModelIndex());
 
	private:
		QList<connectionData> connectionList;

ConnectionListModel(QObject *parent = 0);
    ~ConnectionListModel();

	 //Required items to make this model work
	 int rowCount(const QModelIndex &index = QModelIndex()) const;
	 QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;

	 //required items to be able to edit items
	 bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole);
	 Qt::ItemFlags flags(const QModelIndex &index) const;

	 //Required to be able to resize the model (add & remove shit)
	 bool insertRows(int row, int count, const QModelIndex &parent = QModelIndex());
	 bool removeRows(int row, int count, const QModelIndex &parent = QModelIndex());
	 
	private:
		QList<connectionData> connectionList;

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One thing that I noticed when stepping through my code while trying to add an item was that I'm never calling my setData funciton with a valid index, so it always skips over the code and never emits the signal that the data changed.

So now my question is how do I get a valid index? I thought that calling index(0) would give me the index for the item that I just inserted at the front of the list, but that isn't the case.

Here's the calling code

//where m_pSessoinModel is a connectionlistmodel
	ConnectionListModel::connectionData addMe;
 
	m_pSessionModel->insertRows(0, 1);  //inserting 1 row before row #0
	m_pSessionModel->setData( m_pSessionModel->index(0), &addMe);

//where m_pSessoinModel is a connectionlistmodel
	ConnectionListModel::connectionData addMe;
	
	m_pSessionModel->insertRows(0, 1);  //inserting 1 row before row #0
	m_pSessionModel->setData( m_pSessionModel->index(0), &addMe);

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Any ideas? The examples online are not very helpful here.
Paul

[fullmetalcoder]

So now my question is how do I get a valid index? I thought that calling index(0) would give me the index for the item that I just inserted at the front of the list, but that isn't the case.

index(0) shouldn't even compile AFAIK... it should be index(0, 0) (or index(0, 1) and so on...). An index obtained through the index() method represents a single cell, not a whole row...

besides, your header is slightly wrong... The default role for the setData() function should be Qt:isplayRole as well or am I missing something?

[thomaspu]

The QAbstractListModel defines a default for the column:

virtual QModelIndex index ( int row, int column = 0, const QModelIndex & parent = QModelIndex() ) const

virtual QModelIndex index ( int row, int column = 0, const QModelIndex & parent = QModelIndex() ) const

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But when do you ever get a valid QModelIndex? When I'm calling the insertRows function, I don't know the parent at all. The description in the function reads

Returns the index of the data in row and column with parent.

So If I never have the parent... thats probably why it doesn't work?

Yeah, the role should have just been Qt:isplayRole

Paul

[fullmetalcoder]

When I'm calling the insertRows function, I don't know the parent at all. The description in the function reads So If I never have the parent... thats probably why it doesn't work?l

The point is that you never HAVE any parents anywhere since you're using a table and not a hierarchical (i.e. tree) model. When no parent is involved the parent is the header node which is represented by an invalid parent (which is the default parent passed to all methods that require a parent BTW... )

[thomaspu]

Ok, that makes sense since this is just a flat model. So any ideas why nothing shows up on my QListView after I add an item to my model?

Paul

[fullmetalcoder]

May I ask for the full code?

[thomaspu]

Sure, let me put it together. Just a few min...

[thomaspu]

Ok, all you need is attached.

Paul

[fullmetalcoder]

Ok I found the bug... You messed up the rowCount() function... The point in this one is to return the number of connections when the parent passed is the root node (so an invalid index) and to return 0 (no child) when the parent is valid (i.e. one of the connection...)

Note that before I found that I added a columnCount() function so you may also need to add it so as to have your model working properly...

[thomaspu]

Ah, yes, that was it! Yeah, you return the number of connections when the parent is invalid. Which in my case is always cause my list is flat and doesn't have a parent.

Thanks for all the help, I think I'm good to go for a bit!
Paul