QCompleter Class Reference
[QtGui module]

Handling Tree Models

QCompleter can look for completions in tree models, assuming that any item (or sub-item or sub-sub-item) can be unambiguously represented as a string by specifying the path to the item. The completion is then performed one level at a time.

Let's take the example of a user typing in a file system path. The model is a (hierarchical) QDirModel. The completion occurs for every element in the path. For example, if the current text is C:\Wind, QCompleter might suggest Windows to complete the current path element. Similarly, if the current text is C:\Windows\Sy, QCompleter might suggest System.

For this kind of completion to work, QCompleter needs to be able to split the path into a list of strings that are matched at each level. For C:\Windows\Sy, it needs to be split as "C:", "Windows" and "Sy". The default implementation of splitPath(), splits the completionPrefix using QDir::separator() if the model is a QDirModel.

To provide completions, QCompleter needs to know the path from an index. This is provided by pathFromIndex(). The default implementation of pathFromIndex(), returns the data for the completionRole() for list models and the absolute file path if the mode is a QDirModel.

See also QAbstractItemModel, QLineEdit, QComboBox, and Completer Example.

Member Type Documentation

enum QCompleter::CompletionMode

This enum specifies how completions are provided to the user.

See also setCompletionMode().

enum QCompleter::ModelSorting

This enum specifies how the items in the model are sorted.

See also setModelSorting().

Property Documentation

caseSensitivity : Qt::CaseSensitivity

This property holds the case sensitivity of the matching.

The default is Qt::CaseSensitive.

Access functions:

• Qt::CaseSensitivity caseSensitivity () const
• void setCaseSensitivity ( Qt::CaseSensitivity caseSensitivity )

See also completionColumn, completionRole, and modelSorting.

completionColumn : int

This property holds the column in the model in which completions are searched for.

If the popup() is a QListView, it is automatically setup to display this column.

By default, the match column is 0.

Access functions:

• int completionColumn () const
• void setCompletionColumn ( int column )

See also completionRole and caseSensitivity.

completionMode : CompletionMode

This property holds how the completions are provided to the user.

The default value is QCompleter::PopupCompletion.

Access functions:

• CompletionMode completionMode () const
• void setCompletionMode ( CompletionMode mode )

completionPrefix : QString

This property holds the completion prefix used to provide completions.

The completionModel() is updated to reflect the list of possible matches for prefix.

Access functions:

• QString completionPrefix () const
• void setCompletionPrefix ( const QString & prefix )

completionRole : int

This property holds the item role to be used to query the contents of items for matching.

The default role is Qt::EditRole.

Access functions:

• int completionRole () const
• void setCompletionRole ( int role )

See also completionColumn and caseSensitivity.

modelSorting : ModelSorting

This property holds the way the model is sorted.

By default, no assumptions are made about the order of the items in the model that provides the completions.

If the model's data for the completionColumn() and completionRole() is sorted in ascending order, you can set this property to CaseSensitivelySortedModel or CaseInsensitivelySortedModel. On large models, this can lead to significant performance improvements because the completer object can then use a binary search algorithm instead of linear search algorithm.

The sort order (i.e ascending or descending order) of the model is determined dynamically by inspecting the contents of the model.

Note: The performance improvements described above cannot take place when the completer's caseSensitivity is different to the case sensitivity used by the model's when sorting.

Access functions:

• ModelSorting modelSorting () const
• void setModelSorting ( ModelSorting sorting )

See also setCaseSensitivity() and QCompleter::ModelSorting.

wrapAround : bool

This property holds the completions wrap around when navigating through items.

The default is true.

This property was introduced in Qt 4.3.

Access functions:

• bool wrapAround () const
• void setWrapAround ( bool wrap )

Member Function Documentation

QCompleter::QCompleter ( QObject * parent = 0 )

Constructs a completer object with the given parent.

QCompleter::QCompleter ( QAbstractItemModel * model, QObject * parent = 0 )

Constructs a completer object with the given parent that provides completions from the specified model.

QCompleter::QCompleter ( const QStringList & list, QObject * parent = 0 )

Constructs a QCompleter object with the given parent that uses the specified list as a source of possible completions.

QCompleter::~QCompleter ()

Destroys the completer object.

void QCompleter::activated ( const QString & text )   [signal]

This signal is sent when an item in the popup() is activated by the user (by clicking or pressing return). The item's text is given.

void QCompleter::activated ( const QModelIndex & index )   [signal]

This is an overloaded member function, provided for convenience.

This signal is sent when an item in the popup() is activated by the user. (by clicking or pressing return). The item's index in the completionModel() is given.

void QCompleter::complete ( const QRect & rect = QRect() )   [slot]

For QCompleter::PopupCompletion and QCompletion::UnfilteredPopupCompletion modes, calling this function displays the popup displaying the current completions. By default, if rect is not specified, the popup is displayed on the bottom of the widget(). If rect is specified the popup is displayed on the left edge of the rectangle.

For QCompleter::InlineCompletion mode, the highlighted() signal is fired with the current completion.

int QCompleter::completionCount () const

Returns the number of completions for the current prefix. For an unsorted model with a large number of items this can be expensive. Use setCurrentRow() and currentCompletion() to iterate through all the completions.

QAbstractItemModel * QCompleter::completionModel () const

Returns the completion model. The completion model is a read-only list model that contains all the possible matches for the current completion prefix. The completion model is auto-updated to reflect the current completions.

See also completionPrefix and model().

QString QCompleter::currentCompletion () const

Returns the current completion string. This includes the completionPrefix. When used alongside setCurrentRow(), it can be used to iterate through all the matches.

See also setCurrentRow() and currentIndex().

QModelIndex QCompleter::currentIndex () const

Returns the model index of the current completion in the completionModel().

See also setCurrentRow(), currentCompletion(), and model().

int QCompleter::currentRow () const

Returns the current row.

See also setCurrentRow().

void QCompleter::highlighted ( const QString & text )   [signal]

This signal is sent when an item in the popup() is highlighted by the user. It is also sent if complete() is called with the completionMode() set to QCOmpleter::InlineCompletion. The item's text is given.

void QCompleter::highlighted ( const QModelIndex & index )   [signal]

This is an overloaded member function, provided for convenience.

This signal is sent when an item in the popup() is highlighted by the user. It is also sent if complete() is called with the completionMode() set to QCompleter::InlineCompletion. The item's index in the completionModel() is given.

QAbstractItemModel * QCompleter::model () const

Returns the model that provides completion strings.

See also setModel() and completionModel().

QString QCompleter::pathFromIndex ( const QModelIndex & index ) const   [virtual]

Returns the path for the given index. The completer object uses this to obtain the completion text from the underlying model.

The default implementation returns the edit role of the item for list models. It returns the absolute file path if the model is a QDirModel.

See also splitPath().

QAbstractItemView * QCompleter::popup () const

Returns the popup used to display completions.

See also setPopup().

bool QCompleter::setCurrentRow ( int row )

Sets the current row to the row specified. Returns true if successful; otherwise returns false.

This function may be used along with currentCompletion() to iterate through all the possible completions.

See also currentRow(), currentCompletion(), and completionCount().

void QCompleter::setModel ( QAbstractItemModel * model )

Sets the model which provides completions to model. The model can be list model or a tree model. If a model has been already previously set and it has the QCompleter as its parent, it is deleted.

For convenience, if model is a QDirModel, QCompleter switches its caseSensitivity to Qt::CaseInsensitive on Windows and Qt::CaseSensitive on other platforms.

See also completionModel(), modelSorting, and Handling Tree Models.

void QCompleter::setPopup ( QAbstractItemView * popup )

Sets the popup used to display completions to popup. QCompleter takes ownership of the view.

A QListView is automatically created when the completionMode() is set to QCompleter::PopupCompletion or QCompleter::UnfilteredPopupCompletion. The default popup displays the completionColumn().

Ensure that this function is called before the view settings are modified. This is required since view's properties may require that a model has been set on the view (for example, hiding columns in the view requires a model to be set on the view).

See also popup().

void QCompleter::setWidget ( QWidget * widget )

Sets the widget for which completion are provided for to widget. This function is automatically called when a QCompleter is set on a QLineEdit using QLineEdit::setCompleter() or on a QComboBox using QComboBox::setCompleter(). The widget needs to be set explicitly when providing completions for custom widgets.

See also widget(), setModel(), and setPopup().

QStringList QCompleter::splitPath ( const QString & path ) const   [virtual]

Splits the given path into strings that are used to match at each level in the model().

The default implementation of splitPath() splits a file system path based on QDir::separator() when the sourceModel() is a QDirModel.

When used with list models, the first item in the returned list is used for matching.

See also pathFromIndex() and Handling Tree Models.

QWidget * QCompleter::widget () const

Returns the widget for which the completer object is providing completions.

See also setWidget().