Building Tree view from Table view which is already build.

[DURGAPRASAD NEELAM]

Hi,

I have already build table view (by customizing QAbstractItemModel & QTableView).
My table view looks as below



Level Name Rank Sec
0 Rajesh 1 A
1 Krish 2 A
2 Ram 3 B
1 Krish 4 C
0 Krish 5 B
1 Krish 6 a
1 Krish 7 A
0 Rajesh 1 A
1 Krish 2 A
2 Ram 3 B
0 Rajesh 1 A
1 Krish 2 A
2 Ram 3 B


Now based on the level column I need to build the tree, Is it possible to re use the same model(from table view) and create tree view based on level column ?
or do I need to create separate new model for tree again. If it is possible please let me know what i need to implement for this.

Tree view : all the Level 0's are parents, followed by 1's are childs of 0's and 2's are childs of 1's.

Thanks in Advance :-)

[jefftee]

Your model would need to maintain data such that a parent/child relationship is maintained so that your QTreeView can display the parent/child hierarchy.

You should be able to also use the same model to display a QTableView, your model would essentially need to present data for all of the leaf nodes, with the Level of the parent being returned as one of the columns, etc.

[anda_skoa]

While it is possible to change structure with a proxy model, it is not something I would recommend unless you are already quite skilled with the model/view internals.

Creating a tree model that works on the same data as your table model sounds a lot easier.

Cheers,
_

[DURGAPRASAD NEELAM]

Hi, I am implementing Lazy population tree view.

have implemented hasChilderen(), fetchMore and canFetchMore() functions as below.
I am getting the Error: QSortFilterProxyModel: invalid inserted rows reported by source model;

Please let me know the problem.


bool TreeModel::canFetchMore(const QModelIndex &parent ) const
{
if(!parent.isValid())
return true;

if(m_totalRowCount > m_lastreadRowIndex) //I am storing lst read row value
{
return true;
}

return false;
}

void DebugTreeModel::fetchMore(const QModelIndex& parent)
{

//to fect readRows od records (rows) from sql
int readRows = 1000;

if( m_totalRowCount < ( readRows + m_lastreadRowIndex ) )
{
readRows = m_totalRowCount - m_lastreadRowIndex;
}

//will get me last row number
qint64 lastRow = m_lastreadRowIndex ;

emit fetchMoreData(readRows); //will fecth readRows number of records form the sql and form tree

qint64 parentsInFetchedData = getZerosInFetchedData();


//i have writtem logic so that, next inserted row should be 0 (so parent should be m_rootItem always (it is my top most parent))
//so I am passing m_rootItem as root and last inserted row number, num of row to insert.
beginInsertRows(QModelIndex(), lastRow , lastRow+parentsInFetchedData -1 ); //same result for beginInsertRows(parent, lastRow , lastRow+parentsInFetchedData -1 );
endInsertRows();
}

[jefftee]

What have you done to debug this? When you are inserting rows, what range of row numbers are you passing to beginInsertRows, etc?

Also, I believe someone else had mentioned model test as a good way to debug models. Have you tried that?

Edit: I would add that trying to implement canFetchMore and fetchMore for a model that can't properly insert data seems like putting the cart before horse to me. Focus on getting the basics working before you try to pimp out your model!

[wysota]

Hi, I am implementing Lazy population tree view.

have implemented hasChilderen(), fetchMore and canFetchMore() functions as below.
I am getting the Error: QSortFilterProxyModel: invalid inserted rows reported by source model;

Please let me know the problem.


This is a cross-post from http://www.qtcentre.org/threads/62245-Need-to-show-SQL-data-in-tree-view-with-lazy-loading

[DURGAPRASAD NEELAM]

While it is possible to change structure with a proxy model, it is not something I would recommend unless you are already quite skilled with the model/view internals._

Could you please explain little more about this, small example or any link to explore would be great :-)

Thanks.