QAbstractListModel Class Reference

The QAbstractListModel class provides an abstract model that can be subclassed to create one-dimensional list models. More...

 #include <QAbstractListModel>

Inherits: QAbstractItemModel.

Inherited by: QStringListModel.

Public Functions

QAbstractListModel ( QObject * parent = 0 )
~QAbstractListModel ()

Reimplemented Public Functions

virtual bool dropMimeData ( const QMimeData * data, Qt::DropAction action, int row, int column, const QModelIndex & parent )
virtual QModelIndex index ( int row, int column = 0, const QModelIndex & parent = QModelIndex() ) const

Additional Inherited Members

Detailed Description

The QAbstractListModel class provides an abstract model that can be subclassed to create one-dimensional list models.

QAbstractListModel provides a standard interface for models that represent their data as a simple non-hierarchical sequence of items. It is not used directly, but must be subclassed.

Since the model provides a more specialized interface than QAbstractItemModel, it is not suitable for use with tree views; you will need to subclass QAbstractItemModel if you want to provide a model for that purpose. If you need to use a number of list models to manage data, it may be more appropriate to subclass QAbstractTableModel class instead.

Simple models can be created by subclassing this class and implementing the minimum number of required functions. For example, we could implement a simple read-only QStringList-based model that provides a list of strings to a QListView widget. In such a case, we only need to implement the rowCount() function to return the number of items in the list, and the data() function to retrieve items from the list.

Since the model represents a one-dimensional structure, the rowCount() function returns the total number of items in the model. The columnCount() function is implemented for interoperability with all kinds of views, but by default informs views that the model contains only one column.

Subclassing

When subclassing QAbstractListModel, you must provide implementations of the rowCount() and data() functions. Well behaved models also provide a headerData() implementation.

For editable list models, you must also provide an implementation of setData(), implement the flags() function so that it returns a value containing Qt::ItemIsEditable.

Note that QAbstractListModel provides a default implementation of columnCount() that informs views that there is only a single column of items in this model.

Models that provide interfaces to resizable list-like data structures can provide implementations of insertRows() and removeRows(). When implementing these functions, it is important to call the appropriate functions so that all connected views are aware of any changes:

Note: Some general guidelines for subclassing models are available in the Model Subclassing Reference.

See also Model Classes, Model Subclassing Reference, QAbstractItemView, QAbstractTableModel, and Item Views Puzzle Example.

Member Function Documentation

QAbstractListModel::QAbstractListModel ( QObject * parent = 0 )

Constructs an abstract list model with the given parent.

QAbstractListModel::~QAbstractListModel ()

Destroys the abstract list model.

bool QAbstractListModel::dropMimeData ( const QMimeData * data, Qt::DropAction action, int row, int column, const QModelIndex & parent ) [virtual]

Reimplemented from QAbstractItemModel::dropMimeData().

QModelIndex QAbstractListModel::index ( int row, int column = 0, const QModelIndex & parent = QModelIndex() ) const [virtual]

Reimplemented from QAbstractItemModel::index().

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

See also parent().

Notes provided by the Qt Community
Informative
  • 4

Votes: 7

Coverage: Qt library 4.7, 4.8, 5.0

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Lab Rat
4 notes

Nokia Certified Qt Developer

Using QAbstractListModel derived models in QTreeView

Ignoring the documentation’s advice I tend to use QAbstractListModel derived models with QTreeView whenever the model is not hierarchic and I need a listview like widget with multiple columns.

You basically just have to reimplement columnCount to do that:

  1. class MyModel : public QAbstractListModel
  2. {
  3.   Q_OBJECT
  4.  
  5. public:
  6.  
  7.   enum Column {
  8.     ColFirst,
  9.     ColSecond,
  10.     ColMax
  11.   };
  12.  
  13.   MyModel(QObject *parent = 0) : QAbstractListModel(parent)
  14.   {
  15.   }
  16.  
  17.   // Qt Model/View interface
  18.   int rowCount(const QModelIndex &parent = QModelIndex()) const { Q_UNUSED(parent); return m_entries.count(); }
  19.   int columnCount(const QModelIndex &parent = QModelIndex()) const { Q_UNUSED(parent); return ColMax; }
  20.  
  21.   QVariant data(const QModelIndex &index, int role) const
  22.   {
  23.      ...
  24.   }
  25.  
  26.   QVariant headerData(int section, Qt::Orientation o, int role) const
  27.   {
  28.      ...
  29.   }
  30.  
  31.   void setEntries(const QList<MyData> &entries) { m_entries = entries; reset(); }
  32.  
  33. protected:
  34.   QList<MyData> m_entries;
  35. }

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