com.trolltech.qt.gui
Class QCompleter

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.core.QObject
                  extended by com.trolltech.qt.gui.QCompleter
All Implemented Interfaces:
QtJambiInterface

public class QCompleter
extends QObject

The QCompleter class provides completions based on an item model. You can use QCompleter to provide auto completions in any Qt widget, such as QLineEdit and QComboBox. When the user starts typing a word, QCompleter suggests possible ways of completing the word, based on a word list. The word list is provided as a QAbstractItemModel. (For simple applications, where the word list is static, you can pass a QStringList to QCompleter's constructor.)

Basic Usage

A QCompleter is used typically with a
QLineEdit or QComboBox. For example, here's how to provide auto completions from a simple word list in a QLineEdit:
        List<String> wordList = new Vector<String>();
        wordList.add("alpha");
        wordList.add("omega");
        wordList.add("omicron");
        wordList.add("zeta");

        QLineEdit lineEdit = new QLineEdit();

        QCompleter completer = new QCompleter(wordList);
        completer.setCaseSensitivity(Qt.CaseSensitivity.CaseInsensitive);
        lineEdit.setCompleter(completer);
        
A QDirModel can be used to provide auto completion of file names. For example:
        QCompleter completer2 = new QCompleter();
        completer2.setModel(new QDirModel(completer2));
        lineEdit.setCompleter(completer2);
        
To set the model on which QCompleter should operate, call setModel(). By default, QCompleter will attempt to match the completion prefix (i.e., the word that the user has started typing) against the Qt::EditRole data stored in column 0 in the model case sensitively. This can be changed using setCompletionRole(), setCompletionColumn(), and setCaseSensitivity().

If the model is sorted on the column and role that are used for completion, you can call setModelSorting() with either QCompleter::CaseSensitivelySortedModel or QCompleter::CaseInsensitivelySortedModel as the argument. On large models, this can lead to significant performance improvements, because QCompleter can then use binary search instead of linear search.

The model can be a list model, a table model, or a tree model. Completion on tree models is slightly more involved and is covered in the Handling Tree Models section below.

The completionMode() determines the mode used to provide completions to the user.

Iterating Through Completions

To retrieve a single candidate string, call setCompletionPrefix() with the text that needs to be completed and call currentCompletion(). You can iterate through the list of completions as below:
            for (int i = 0; completer.setCurrentRow(i); i++)
                System.out.println(completer.currentCompletion() + " is match number " + i);
        
completionCount() returns the total number of completions for the current prefix. completionCount() should be avoided when possible, since it requires a scan of the entire model.

The Completion Model

completionModel() return a list model that contains all possible completions for the current completion prefix, in the order in which they appear in the model. This model can be used to display the current completions in a custom view. Calling setCompletionPrefix() automatically refreshes the completion model.

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 edit role for list models and the absolute file path if the mode is a QDirModel.

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


Nested Class Summary
static class QCompleter.CompletionMode
          This enum specifies how completions are provided to the user.
static class QCompleter.ModelSorting
          This enum specifies how the items in the model are sorted.
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 QSignalEmitter.Signal1 activated
          This signal takes 1 generic argument(s).
 QSignalEmitter.Signal1 activatedIndex
          This signal takes 1 generic argument(s).
 QSignalEmitter.Signal1 highlighted
          This signal takes 1 generic argument(s).
 QSignalEmitter.Signal1 highlightedIndex
          This signal takes 1 generic argument(s).
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QCompleter()
          Constructs a completer object with the given parent.
QCompleter(java.util.List completions)
          Constructs a QCompleter object with the given parent that uses the specified list as a source of possible completions.
QCompleter(java.util.List completions, QObject parent)
          Constructs a QCompleter object with the given parent that uses the specified list as a source of possible completions.
QCompleter(QAbstractItemModel model)
          Constructs a completer object with the given parent that provides completions from the specified model.
QCompleter(QAbstractItemModel model, QObject parent)
          Constructs a completer object with the given parent that provides completions from the specified model.
QCompleter(QObject parent)
          Constructs a completer object with the given parent.
 
Method Summary
 Qt.CaseSensitivity caseSensitivity()
          This property holds the case sensitivity of the matching.
 void complete()
          For QCompleter::PopupCompletion and QCompletion::UnfilteredPopupCompletion modes, calling this function displays the popup displaying the current completions.
 void complete(QRect rect)
          For QCompleter::PopupCompletion and QCompletion::UnfilteredPopupCompletion modes, calling this function displays the popup displaying the current completions.
 int completionColumn()
          This property holds the column in the model in which completions are searched for.
 int completionCount()
          Returns the number of completions for the current prefix.
 QCompleter.CompletionMode completionMode()
          This property holds how the completions are provided to the user.
 QAbstractItemModel completionModel()
          Returns the completion model.
 java.lang.String completionPrefix()
          This property holds the completion prefix used to provide completions.
 int completionRole()
          This property holds the item role to be used to query the contents of items for matching.
 java.lang.String currentCompletion()
          Returns the current completion string.
 com.trolltech.qt.core.QModelIndex currentIndex()
          Returns the model index of the current completion in the completionModel().
 int currentRow()
          Returns the current row.
 QAbstractItemModel model()
          Returns the model that provides completion strings.
 QCompleter.ModelSorting modelSorting()
          This property holds the way the model is sorted.
 java.lang.String pathFromIndex(com.trolltech.qt.core.QModelIndex index)
          Returns the path for the given index.
 QAbstractItemView popup()
          Returns the popup used to display completions.
 void setCaseSensitivity(Qt.CaseSensitivity caseSensitivity)
          This property holds the case sensitivity of the matching.
 void setCompletionColumn(int column)
          This property holds the column in the model in which completions are searched for.
 void setCompletionMode(QCompleter.CompletionMode mode)
          This property holds how the completions are provided to the user.
 void setCompletionPrefix(java.lang.String prefix)
          This property holds the completion prefix used to provide completions.
 void setCompletionRole(int role)
          This property holds the item role to be used to query the contents of items for matching.
 boolean setCurrentRow(int row)
          Sets the current row to the row specified.
 void setModel(QAbstractItemModel c)
          Sets the model which provides completions to model.
 void setModelSorting(QCompleter.ModelSorting sorting)
          This property holds the way the model is sorted.
 void setPopup(QAbstractItemView popup)
          Sets the popup used to display completions to popup.
 void setWidget(QWidget widget)
          Sets the widget for which completion are provided for to widget.
 void setWrapAround(boolean wrap)
          This property holds the completions wrap around when navigating through items.
 java.util.List splitPath(java.lang.String path)
          Splits the given path into strings that are used to match at each level in the model().
 QWidget widget()
          Returns the widget for which the completer object is providing completions.
 boolean wrapAround()
          This property holds the completions wrap around when navigating through items.
 
Methods inherited from class com.trolltech.qt.core.QObject
childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
clone, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Field Detail

activatedIndex

public final QSignalEmitter.Signal1 activatedIndex

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.core.QModelIndex(named: text)>:

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.


activated

public final QSignalEmitter.Signal1 activated

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <java.lang.String(named: text)>:

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.


highlightedIndex

public final QSignalEmitter.Signal1 highlightedIndex

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.core.QModelIndex(named: text)>:

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.


highlighted

public final QSignalEmitter.Signal1 highlighted

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <java.lang.String(named: text)>:

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.

Constructor Detail

QCompleter

public QCompleter(QAbstractItemModel model)
Constructs a completer object with the given parent that provides completions from the specified model.


QCompleter

public QCompleter(QAbstractItemModel model,
                  QObject parent)
Constructs a completer object with the given parent that provides completions from the specified model.


QCompleter

public QCompleter()
Constructs a completer object with the given parent.


QCompleter

public QCompleter(QObject parent)
Constructs a completer object with the given parent.


QCompleter

public QCompleter(java.util.List completions)
Constructs a QCompleter object with the given parent that uses the specified list as a source of possible completions.


QCompleter

public QCompleter(java.util.List completions,
                  QObject parent)
Constructs a QCompleter object with the given parent that uses the specified list as a source of possible completions.

Method Detail

caseSensitivity

public final Qt.CaseSensitivity caseSensitivity()
This property holds the case sensitivity of the matching. The default is Qt::CaseSensitive .

See also:
completionColumn, completionRole, and modelSorting.


complete

public final void complete()
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.


complete

public final void complete(QRect rect)
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.


completionColumn

public final int completionColumn()
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.

See also:
completionRole, and caseSensitivity.


completionCount

public final int completionCount()
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.


completionMode

public final QCompleter.CompletionMode completionMode()
This property holds how the completions are provided to the user. The default value is QCompleter::PopupCompletion .


completionModel

public final QAbstractItemModel completionModel()
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().


completionPrefix

public final java.lang.String completionPrefix()
This property holds the completion prefix used to provide completions. The completionModel() is updated to reflect the list of possible matches for prefix.


completionRole

public final int completionRole()
This property holds the item role to be used to query the contents of items for matching. The default role is Qt::EditRole .

See also:
completionColumn, and caseSensitivity.


currentCompletion

public final java.lang.String currentCompletion()
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().


currentIndex

public final com.trolltech.qt.core.QModelIndex currentIndex()
Returns the model index of the current completion in the completionModel().

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


currentRow

public final int currentRow()
Returns the current row.

See also:
setCurrentRow().


model

public final QAbstractItemModel model()
Returns the model that provides completion strings.

See also:
setModel(), and completionModel().


modelSorting

public final QCompleter.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.

See also:
setCaseSensitivity(), and QCompleter::ModelSorting .


popup

public final QAbstractItemView popup()
Returns the popup used to display completions.

See also:
setPopup().


setCaseSensitivity

public final void setCaseSensitivity(Qt.CaseSensitivity caseSensitivity)
This property holds the case sensitivity of the matching. The default is Qt::CaseSensitive .

See also:
completionColumn, completionRole, and modelSorting.


setCompletionColumn

public final void setCompletionColumn(int column)
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.

See also:
completionRole, and caseSensitivity.


setCompletionMode

public final void setCompletionMode(QCompleter.CompletionMode mode)
This property holds how the completions are provided to the user. The default value is QCompleter::PopupCompletion .


setCompletionPrefix

public final void setCompletionPrefix(java.lang.String prefix)
This property holds the completion prefix used to provide completions. The completionModel() is updated to reflect the list of possible matches for prefix.


setCompletionRole

public final void setCompletionRole(int role)
This property holds the item role to be used to query the contents of items for matching. The default role is Qt::EditRole .

See also:
completionColumn, and caseSensitivity.


setCurrentRow

public final boolean 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().


setModel

public final void setModel(QAbstractItemModel c)
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.


setModelSorting

public final void setModelSorting(QCompleter.ModelSorting sorting)
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.

See also:
setCaseSensitivity(), and QCompleter::ModelSorting .


setPopup

public final void 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().


setWidget

public final void 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().


setWrapAround

public final void setWrapAround(boolean wrap)
This property holds the completions wrap around when navigating through items. The default is true.


widget

public final QWidget widget()
Returns the widget for which the completer object is providing completions.

See also:
setWidget().


wrapAround

public final boolean wrapAround()
This property holds the completions wrap around when navigating through items. The default is true.


pathFromIndex

public java.lang.String pathFromIndex(com.trolltech.qt.core.QModelIndex index)
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().


splitPath

public java.util.List splitPath(java.lang.String path)
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.