Creating a QAbstractItemModel for QTreeView

hi

- I want know how subclassin a QAbstractItemModel to create a model for QTreeView

- how can i create my model like QDirModel using QAbstractItemModel ? i want display more informations of files and directories in a QTreeView (owner .....)

thank you

Quote:

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Originally Posted by hbill

- I want know how subclassin a QAbstractItemModel to create a model for QTreeView

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There are many resources available on that topic. Take a look at the [wiki=QAbstractItemModel]wiki[/wiki].

Quote:

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- how can i create my model like QDirModel using QAbstractItemModel ? i want display more informations of files and directories in a QTreeView (owner .....)

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Subclass QDirModel and reimplement appropriate methods calling base class implementations where needed.

Quote:

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Originally Posted by hbill

hi

- I want know how subclassin a QAbstractItemModel to create a model for QTreeView
model like QDirModel
thank you

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you can build tree from QStandardItemModel begin to read xml tree or sql tree demo
http://www.klempert.de/nested_sets/demo/

run on mysql or on sqlite3
each level become a QList<QStandardItem *>

model = new QStandardItemModel();
model->invisibleRootItem()->appendRow(QList<QStandardItem *>);
sublevel the first QStandardItem appendRow(QList<QStandardItem *>)

code on http://www.qtforum.de/forum/viewtopic.php?t=5845

To swap from one model to other you can use:
http://fop-miniscribus.googlecode.co....0/ModelSwap.h
http://fop-miniscribus.googlecode.co.../ModelSwap.cpp
I use this to print on tree or tableview to QTextDocument

thank you
can you help me to subclassing QDirModel, :(

Quote:

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Originally Posted by hbill

can you help me to subclassing QDirModel, :(

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What's causing problems? What did you try so far? Let's say you wanted to add one column:

Code:

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class MyDirModel : public QDirModel
{
   public:
      ...
      // reimplement columnCount()
      virtual int columnCount(const QModelIndex& parent = QModelIndex()) const;
      ...
};
 
int MyDirModel::columnCount(const QModelIndex& parent) const
{
   // call base class implementation and add 1 to whatever it returns
   return QDirModel::columnCount(parent) + 1;
}

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This is just an example to get you going. Most likely you don't want to return 1 as column count when the base class returns 0. Next thing to do is to reimplement data() and make it handle this additional column.

hi

Code:

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MyDirModel:: MyDirModel(QObject *parent)
     : QDirModel(parent)
{
    removeColumn(QDirModel::columnCount() - 1);
}
 
 
MyDirModel::~MyDirModel()
{
}
 
 
int MyDirModel::columnCount(const QModelIndex& parent) const
{
   return QDirModel::columnCount(parent) + 2  ;
}
 
QVariant MyDirModel::data(const QModelIndex & index, int role) const
{
    if( role==Qt::DisplayRole )
    {
        if( index.column()==QDirModel::columnCount() )
            return fileInfo( index ).owner();
        else 
            if( index.column()==QDirModel::columnCount() +1 )
                return fileInfo( index ).group();
    }
return QDirModel::data(index, role);
}

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the column "last modified" was not removed and the new columns are empty :o

QDirModel does not implement QAbstractItemModel::removeColums() so you can't use it. Either hide it from the view or make the subclass return alternative data for that particular column. Start with checking out if anything shows up in those columns when you return a fixed test string. After that, continue with investigating whether the QFileInfo returned by fileInfo() is ok.

hi

Code:

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QVariant MyDirModel::data(const QModelIndex & index, int role) const
      {
    QMessageBox msgBox;
    //msgBox.exec();//ok
          if( role==Qt::DisplayRole )
          {
        //msgBox.exec();//ok
              if( index.column()==QDirModel::columnCount() )//problem
        {
        //msgBox.exec();//not ok
                  return fileInfo( index ).owner();
        }
              else
                  if( index.column()==QDirModel::columnCount() +1 )//problem
                      return fileInfo( index ).group();
            else
                if( index.column()==QDirModel::columnCount() -1 )
                {
                    //msgBox.exec();//ok
                    return fileInfo( index ).owner();//ok
                }
          }
      return QDirModel::data(index, role);
      }

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i have a problem with the new columns !!! :confused:

Quote:

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Originally Posted by hbill

i have a problem with the new columns !!! :confused:

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Could you be a bit more verbose about the problem, please?

Quote:

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Originally Posted by jpn

Could you be a bit more verbose about the problem, please?

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Yeah... a more verbose version is "they are not working!" :D

Sorry, couldn't resist myself...

the test

Code:

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if( index.column()==id_column )

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is virified if id_column <QDirModel::columnCount()
but no if id_column >=QDirModel::columnCount()

Could you check if your columnCount() method is called at all?

Did you ever find a solution to the column data not being added?

Your problem may have been similar to mine. What version of Qt are you using. I upgraded from 4.3.2 to 4.4.1 on solaris, and my problems went away.