[Solved] QAbstractTableModel rowsInserted (const QModelIndex & parent, int start, int end) signal

ZapB

Andre, not in the implementation no.

The problem is in the connect statement. You should not pass argument names in to the connect call. Your connect statement should look like this:

@
connect(m_Model, SIGNAL(rowsInserted( const QModelIndex&, int, int) ),
this, SLOT(modelRowsInserted ( const QModelIndex&, int, int) ) );
@

andre

[quote author="ZapB" date="1304519890"]Andre, not in the implementation no.[/quote]
"D'oh":http://en.wikipedia.org/wiki/D'oh! !
Of course not.

ZabB is absolutely right.

WilliamU

Hi Guys,

The (schoolboy error of mine) with arguments in the connect(ion) now removed has solved the error, thank you but that still doesn't explain why the signal doesn't appear in the auto-completion list!

Thank's again.

--
William

andre

That, I think, would be an issue of Qt Creator.

ZapB

That's a separate issue and likely related to Qt-Creator's code model. Which version of creator are you using?

WilliamU

To answer your question ZapB I am using v2.1.0 (Qt 4.7.1) 32 bit on Windows Vista x64

Also now I have my signal connected I don't get notification of any rows being added!

I have changed the code to this:
@
if (m_Model)
{
if (connect(m_Model, SIGNAL(rowsInserted(const QModelIndex &, int, int)), this, SLOT(modelRowsInserted(QModelIndex, int, int))))
{
// Load model from file.
if (m_Model->load("./input.xml"))
{
// Assign the model to the view
ui->myModelView->setModel(m_Model);
}
}
}
@

With my slot being:
@
void MainWindow::modelRowsInserted ( const QModelIndex & parent, int start, int end )
{
qDebug() << "Rows Added to Model" ;
}
@

But I never see any output in the Application Output console even though my model correctly displays the (processed) content of the input file. In this instance I would have expected to see two lines in the output console based on the content of the file and what is correctly displayed in the View.

--
William

andre

That might suggest that your model is not correctly implemented.

ZapB

I agree with Andre. Do you call beginInsertRows() and endInsertRows() around the place where you actually modify your internal data structure? Can you post this piece of code please?

WilliamU

Hi,

Well I cannot see what else I am missing as as far as I can tell I have no need to re-implement anything other than those already listed as this is a read only model. I am relying on (my assumption) that this signal will (should) get emitted (via the default implementation) when a new row is inserted.

--
William

giesbert

Hi William,

who should add rows that emit this signal?
If you change the content of the model, you have to call the defined methods, like begine/end insert Rows/columns. Same for remove.
Without calling these, the signals will not be emitted.

EDIT: I assume, the content of your model is static? Or is it dynamic? if it is dynamic, the model is responsible for notifying the clients.

ZapB

Read-only model means read-only as far as the QAbstractItemModel's interface is concerned. ie an attached view will not allow users to edit the model. However, you are still changing the model when you load your data and so you need to call beginInsertRows() and endInsertRows() around the place where you modify your underlying data structure. It is the call to endInsertRows() that causes your missing signal to be emitted. How else would the model know what you are doing behind it's back?

WilliamU

Thanks Gerolf and ZapB, it's just got very bright in here. :-)

Thanks again.

--
William

ZapB

No worries. I remember the pains of learning the modelview architecture. It can be confusing. The trick is to remember that QAbstractItemModel is only an interface to your data that us used by the views. You have to nudge it it the right direction when you change your data behind it's back by calling the appropriate protected functions.

Good luck with the rest of your project!