QListBox

NAME

SYNOPSIS

Inherits QScrollView.

Public Members

Public Slots

Signals

Properties

Protected Members

DESCRIPTION

This is typically a single-column list in which either no item or one item is selected, but it can also be used in many other ways.

QListBox will add scroll bars as necessary, but it isn't intended for really big lists. If you want more than a few thousand items, it's probably better to use a different widget mainly because the scroll bars won't provide very good navigation, but also because QListBox may become slow with huge lists. (See QListView and QTable for possible alternatives.)

There are a variety of selection modes described in the QListBox::SelectionMode documentation. The default is Single selection mode, but you can change it using setSelectionMode(). (setMultiSelection() is still provided for compatibility with Qt 1.x. We recommend using setSelectionMode() in all code.)

Because QListBox offers multiple selection it must display keyboard focus and selection state separately. Therefore there are functions both to set the selection state of an item, i.e. setSelected(), and to set which item displays keyboard focus, i.e. setCurrentItem().

The list box normally arranges its items in a single column and adds a vertical scroll bar if required. It is possible to have a different fixed number of columns (setColumnMode()), or as many columns as will fit in the list box's assigned screen space (setColumnMode(FitToWidth)), or to have a fixed number of rows (setRowMode()) or as many rows as will fit in the list box's assigned screen space (setRowMode(FitToHeight)). In all these cases QListBox will add scroll bars, as appropriate, in at least one direction.

If multiple rows are used, each row can be as high as necessary (the normal setting), or you can request that all items will have the same height by calling setVariableHeight(FALSE). The same applies to a column's width, see setVariableWidth().

The QListBox's items are QListBoxItem objects. QListBox provides methods to insert new items as strings, as pixmaps, and as QListBoxItem * (insertItem() with various arguments), and to replace an existing item with a new string, pixmap or QListBoxItem (changeItem() with various arguments). You can also remove items singly with removeItem() or clear() the entire list box. Note that if you create a QListBoxItem yourself and insert it, QListBox takes ownership of the item.

You can also create a QListBoxItem, such as QListBoxText or QListBoxPixmap, with the list box as first parameter. The item will then append itself. When you delete an item it is automatically removed from the list box.

The list of items can be arbitrarily large; QListBox will add scroll bars if necessary. QListBox can display a single-column (the common case) or multiple-columns, and offers both single and multiple selection. QListBox does not support multiple-column items (but QListView and QTable do), or tree hierarchies (but QListView does).

The list box items can be accessed both as QListBoxItem objects (recommended) and using integer indexes (the original QListBox implementation used an array of strings internally, and the API still supports this mode of operation). Everything can be done using the new objects, and most things can be done using indexes.

Each item in a QListBox contains a QListBoxItem. One of the items can be the current item. The currentChanged() signal and the highlighted() signal are emitted when a new item becomes current, e.g. because the user clicks on it or QListBox::setCurrentItem() is called. The selected() signal is emitted when the user double-clicks on an item or presses Enter on the current item.

If the user does not select anything, no signals are emitted and currentItem() returns -1.

A list box has WheelFocus as a default focusPolicy(), i.e. it can get keyboard focus by tabbing, clicking and through the use of the mouse wheel.

New items can be inserted using insertItem(), insertStrList() or insertStringList(). inSort() is obsolete because this method is quite inefficient. It's preferable to insert the items normally and call sort() afterwards, or to insert a sorted QStringList().

By default, vertical and horizontal scroll bars are added and removed as necessary. setHScrollBarMode() and setVScrollBarMode() can be used to change this policy.

If you need to insert types other than strings and pixmaps, you must define new classes which inherit QListBoxItem.

Warning: The list box assumes ownership of all list box items and will delete them when it does not need them any more.

See also QListView, QComboBox, QButtonGroup, GUI Design Handbook: List Box (two sections), and Advanced Widgets.  

Member Type Documentation

QListBox::LayoutMode

QListBox::FixedNumber - There is a fixed number of rows (or columns).

QListBox::FitToWidth - There are as many columns as will fit on-screen.

QListBox::FitToHeight - There are as many rows as will fit on-screen.

QListBox::Variable - There are as many rows as are required by the column mode. (Or as many columns as required by the row mode.)

Example: When you call setRowMode( FitToHeight ), columnMode() automatically becomes Variable to accommodate the row mode you've set.  

QListBox::SelectionMode

QListBox::Single - When the user selects an item, any already-selected item becomes unselected and the user cannot unselect the selected item. This means that the user can never clear the selection, even though the selection may be cleared by the application programmer using QListBox::clearSelection().

QListBox::Multi - When the user selects an item the selection status of that item is toggled and the other items are left alone. Also, multiple items can be selected by dragging the mouse while the left mouse button is kept pressed.

QListBox::Extended - When the user selects an item the selection is cleared and the new item selected. However, if the user presses the Ctrl key when clicking on an item, the clicked item gets toggled and all other items are left untouched. And if the user presses the Shift key while clicking on an item, all items between the current item and the clicked item get selected or unselected, depending on the state of the clicked item. Also, multiple items can be selected by dragging the mouse while the left mouse button is kept pressed.

QListBox::NoSelection - Items cannot be selected.

In other words, Single is a real single-selection list box, Multi is a real multi-selection list box, Extended is a list box in which users can select multiple items but usually want to select either just one or a range of contiguous items, and NoSelection is for a list box where the user can look but not touch.  

MEMBER FUNCTION DOCUMENTATION

QListBox::QListBox ( QWidget * parent = 0, const char * name = 0, WFlags f = 0 )

Performance is boosted by modifying the widget flags f so that only part of the QListBoxItem children is redrawn. This may be unsuitable for custom QListBoxItem classes, in which case WStaticContents and WNoAutoErase should be cleared immediately after construction.

See also QWidget::clearWFlags() and Qt::WidgetFlags.  

QListBox::~QListBox ()

bool QListBox::autoBottomScrollBar () const

Returns TRUE if hScrollBarMode() is Auto; otherwise returns FALSE.  

bool QListBox::autoScrollBar () const

Returns TRUE if vScrollBarMode() is Auto; otherwise returns FALSE.  

bool QListBox::bottomScrollBar () const

Returns FALSE if vScrollBarMode() is AlwaysOff; otherwise returns TRUE.  

int QListBox::cellHeight ( int i ) const

Returns the item height of item i.

See also itemHeight().  

int QListBox::cellHeight () const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Returns the item height of the first item, item 0.

See also itemHeight().  

int QListBox::cellWidth () const

Returns the maximum item width.

See also maxItemWidth().  

void QListBox::centerCurrentItem ()

This function does exactly the same as ensureCurrentVisible()

See also QListBox::ensureCurrentVisible().  

void QListBox::changeItem ( const QListBoxItem * lbi, int index )

The item that has been changed will become selected.

See also insertItem() and removeItem().  

void QListBox::changeItem ( const QString & text, int index )

Replaces the item at position index with a new list box text item with text text.

The operation is ignored if index is out of range.

See also insertItem() and removeItem().  

void QListBox::changeItem ( const QPixmap & pixmap, int index )

Replaces the item at position index with a new list box pixmap item with pixmap pixmap.

The operation is ignored if index is out of range.

See also insertItem() and removeItem().  

void QListBox::changeItem ( const QPixmap & pixmap, const QString & text, int index )

Replaces the item at position index with a new list box pixmap item with pixmap pixmap and text text.

The operation is ignored if index is out of range.

See also insertItem() and removeItem().  

void QListBox::clear () [slot]

See also removeItem().  

void QListBox::clearSelection () [virtual slot]

Note that a Single selection list box will automatically select an item if it has keyboard focus.

Example: listbox/listbox.cpp.  

void QListBox::clicked ( QListBoxItem * item ) [signal]

Note that you must not delete any QListBoxItem objects in slots connected to this signal.  

void QListBox::clicked ( QListBoxItem * item, const QPoint & pnt ) [signal]

This signal is emitted when the user clicks any mouse button. If item is not 0, the cursor is on item. If item is 0, the mouse cursor isn't on any item.

pnt is the position of the mouse cursor in the global coordinate system (QMouseEvent::globalPos()). (If the click's press and release differs by a pixel or two, pnt is the position at release time.)

Note that you must not delete any QListBoxItem objects in slots connected to this signal.  

LayoutMode QListBox::columnMode () const

void QListBox::contextMenuRequested ( QListBoxItem * item, const QPoint & pos ) [signal]

pos is the position for the context menu in the global coordinate system.  

uint QListBox::count () const

void QListBox::currentChanged ( QListBoxItem * item ) [signal]

See also currentItem and currentItem.  

int QListBox::currentItem () const

QString QListBox::currentText () const

void QListBox::doLayout () const [protected]

void QListBox::doubleClicked ( QListBoxItem * item ) [signal]

void QListBox::ensureCurrentVisible () [virtual slot]

QListBoxItem * QListBox::findItem ( const QString & text, ComparisonFlags compare = BeginsWith ) const

See also Qt::StringComparisonMode.  

int QListBox::findItem ( int yPos ) const [protected]

Returns the index of the item a point (0, yPos).

See also index() and itemAt().  

QListBoxItem * QListBox::firstItem () const

void QListBox::highlighted ( int index ) [signal]

See also currentChanged(), selected(), currentItem, and selectionChanged().  

void QListBox::highlighted ( const QString & ) [signal]

This signal is emitted when the user makes a new item the current item and the item is (or has) a string. The argument is the text of the new current item.

See also currentChanged(), selected(), currentItem, and selectionChanged().  

void QListBox::highlighted ( QListBoxItem * ) [signal]

This signal is emitted when the user makes a new item the current item. The argument is a pointer to the new current item.

See also currentChanged(), selected(), currentItem, and selectionChanged().  

int QListBox::inSort ( const QListBoxItem * lbi )

Using this method is quite inefficient. We suggest to use insertItem() for inserting and sort() afterwards.

Inserts lbi at its sorted position in the list box and returns the position.

All items must be inserted with inSort() to maintain the sorting order. inSort() treats any pixmap (or user-defined type) as lexicographically less than any string.

See also insertItem() and sort().  

int QListBox::inSort ( const QString & text )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Using this method is quite inefficient. We suggest to use insertItem() for inserting and sort() afterwards.

Inserts a new item of text at its sorted position in the list box and returns the position.

All items must be inserted with inSort() to maintain the sorting order. inSort() treats any pixmap (or user-defined type) as lexicographically less than any string.

See also insertItem() and sort().  

int QListBox::index ( const QListBoxItem * lbi ) const

See also item().  

void QListBox::insertItem ( const QListBoxItem * lbi, int index = -1 )

If index is negative or larger than the number of items in the list box, lbi is inserted at the end of the list.

See also insertStrList().

Examples:  

void QListBox::insertItem ( const QListBoxItem * lbi, const QListBoxItem * after )

Inserts the item lbi into the list after the item after, or at the beginning if after is 0.

See also insertStrList().  

void QListBox::insertItem ( const QString & text, int index = -1 )

Inserts a new list box text item with the text text into the list at position index.

If index is negative, text is inserted at the end of the list.

See also insertStrList().  

void QListBox::insertItem ( const QPixmap & pixmap, int index = -1 )

Inserts a new list box pixmap item with the pixmap pixmap into the list at position index.

If index is negative, pixmap is inserted at the end of the list.

See also insertStrList().  

void QListBox::insertItem ( const QPixmap & pixmap, const QString & text, int index = -1 )

Inserts a new list box pixmap item with the pixmap pixmap and the text text into the list at position index.

If index is negative, pixmap is inserted at the end of the list.

See also insertStrList().  

void QListBox::insertStrList ( const QStrList * list, int index = -1 )

If index is negative, list is inserted at the end of the list. If index is too large, the operation is ignored.

Warning: This function uses const char * rather than QString, so we recommend against using it. It is provided so that legacy code will continue to work, and so that programs that certainly will not need to handle code outside a single 8-bit locale can use it. See insertStringList() which uses real QStrings.

Warning: This function is never significantly faster than a loop around insertItem().

See also insertItem() and insertStringList().  

void QListBox::insertStrList ( const QStrList & list, int index = -1 )

Inserts the string list list into the list at position index.

If index is negative, list is inserted at the end of the list. If index is too large, the operation is ignored.

Warning: This function uses const char * rather than QString, so we recommend against using it. It is provided so that legacy code will continue to work, and so that programs that certainly will not need to handle code outside a single 8-bit locale can use it. See insertStringList() which uses real QStrings.

Warning: This function is never significantly faster than a loop around insertItem().

See also insertItem() and insertStringList().  

void QListBox::insertStrList ( const char ** strings, int numStrings = -1, int index = -1 )

Inserts the numStrings strings of the array strings into the list at position index.

If index is negative, insertStrList() inserts strings at the end of the list. If index is too large, the operation is ignored.

Warning: This function uses const char * rather than QString, so we recommend against using it. It is provided so that legacy code will continue to work, and so that programs that certainly will not need to handle code outside a single 8-bit locale can use it. See insertStringList() which uses real QStrings.

Warning: This function is never significantly faster than a loop around insertItem().

See also insertItem() and insertStringList().  

void QListBox::insertStringList ( const QStringList & list, int index = -1 )

If index is negative, list is inserted at the end of the list. If index is too large, the operation is ignored.

Warning: This function is never significantly faster than a loop around insertItem().

See also insertItem() and insertStrList().  

void QListBox::invertSelection () [virtual slot]

bool QListBox::isMultiSelection () const

bool QListBox::isRubberSelecting () const [protected]

bool QListBox::isSelected ( int i ) const

bool QListBox::isSelected ( const QListBoxItem * i ) const

Returns TRUE if item i is selected; otherwise returns FALSE.  

QListBoxItem * QListBox::item ( int index ) const

See also index().

Example: listboxcombo/listboxcombo.cpp.  

QListBoxItem * QListBox::itemAt ( const QPoint & p ) const

Use contentsToViewport() to convert between widget coordinates and viewport coordinates.  

int QListBox::itemHeight ( int index = 0 ) const

If index is too large, this function returns 0.  

QRect QListBox::itemRect ( QListBoxItem * item ) const

bool QListBox::itemVisible ( int index )

bool QListBox::itemVisible ( const QListBoxItem * item )

Returns TRUE if item is at least partly visible; otherwise returns FALSE.  

bool QListBox::itemYPos ( int index, int * yPos ) const [protected]

Returns the vertical pixel-coordinate in *yPos, of the list box item at position index in the list. Returns FALSE if the item is outside the visible area.  

long QListBox::maxItemWidth () const

void QListBox::mouseButtonClicked ( int button, QListBoxItem * item, const QPoint & pos ) [signal]

pos is the position of the mouse cursor in the global coordinate system (QMouseEvent::globalPos()). (If the click's press and release differs by a pixel or two, pos is the position at release time.)

Note that you must not delete any QListBoxItem objects in slots connected to this signal.  

void QListBox::mouseButtonPressed ( int button, QListBoxItem * item, const QPoint & pos ) [signal]

pos is the position of the mouse cursor in the global coordinate system (QMouseEvent::globalPos()).

Note that you must not delete any QListBoxItem objects in slots connected to this signal.  

int QListBox::numCols () const

Returns the number of columns.

See also numColumns.  

int QListBox::numColumns () const

int QListBox::numItemsVisible () const

int QListBox::numRows () const

void QListBox::onItem ( QListBoxItem * i ) [signal]

void QListBox::onViewport () [signal]

void QListBox::paintCell ( QPainter * p, int row, int col ) [virtual protected]

Repaints the cell at row, col using painter p.  

const QPixmap * QListBox::pixmap ( int index ) const

See also text().  

void QListBox::pressed ( QListBoxItem * item ) [signal]

Note that you must not delete any QListBoxItem objects in slots connected to this signal.  

void QListBox::pressed ( QListBoxItem * item, const QPoint & pnt ) [signal]

This signal is emitted when the user presses any mouse button. If item is not 0, the cursor is on item. If item is 0, the mouse cursor isn't on any item.

pnt is the position of the mouse cursor in the global coordinate system (QMouseEvent::globalPos()).

Note that you must not delete any QListBoxItem objects in slots connected to this signal.

See also mouseButtonPressed(), rightButtonPressed(), and clicked().  

void QListBox::removeItem ( int index )

See also insertItem() and clear().  

void QListBox::returnPressed ( QListBoxItem * ) [signal]

void QListBox::rightButtonClicked ( QListBoxItem *, const QPoint & ) [signal]

void QListBox::rightButtonPressed ( QListBoxItem *, const QPoint & ) [signal]

LayoutMode QListBox::rowMode () const

bool QListBox::scrollBar () const

Returns FALSE if vScrollBarMode() is AlwaysOff; otherwise returns TRUE.  

void QListBox::selectAll ( bool select ) [virtual slot]

In Single and NoSelection modes, this function only changes the selection status of currentItem().  

void QListBox::selected ( int index ) [signal]

See also currentChanged(), highlighted(), and selectionChanged().  

void QListBox::selected ( const QString & ) [signal]

This signal is emitted when the user double-clicks on an item or presses Enter on the current item, and the item is (or has) a string. The argument is the text of the selected item.

See also currentChanged(), highlighted(), and selectionChanged().  

void QListBox::selected ( QListBoxItem * ) [signal]

This signal is emitted when the user double-clicks on an item or presses Enter on the current item. The argument is a pointer to the new selected item.

See also currentChanged(), highlighted(), and selectionChanged().  

QListBoxItem * QListBox::selectedItem () const

If no items are selected or the list box is in another selection mode this function returns 0.

See also setSelected() and multiSelection.  

void QListBox::selectionChanged () [signal]

See also selected() and currentItem.  

void QListBox::selectionChanged ( QListBoxItem * item ) [signal]

This signal is emitted when the selection in a Single selection list box changes. item is the newly selected list box item.

See also selected() and currentItem.  

SelectionMode QListBox::selectionMode () const

void QListBox::setAutoBottomScrollBar ( bool enable )

If enable is TRUE sets setHScrollBarMode() to AlwaysOn; otherwise sets setHScrollBarMode() to AlwaysOff.  

void QListBox::setAutoScrollBar ( bool enable )

If enable is TRUE sets setVScrollBarMode() to AlwaysOn; otherwise sets setVScrollBarMode() to AlwaysOff.  

void QListBox::setBottomItem ( int index ) [virtual]

See also topItem.  

void QListBox::setBottomScrollBar ( bool enable )

If enable is TRUE sets setHScrollBarMode() to AlwaysOn; otherwise sets setHScrollBarMode() to AlwaysOff.  

void QListBox::setColumnMode ( LayoutMode ) [virtual]

void QListBox::setColumnMode ( int ) [virtual]

void QListBox::setCurrentItem ( int index ) [virtual]

void QListBox::setCurrentItem ( QListBoxItem * i ) [virtual]

Sets the current item to the QListBoxItem i.  

void QListBox::setMultiSelection ( bool multi )

void QListBox::setRowMode ( LayoutMode ) [virtual]

void QListBox::setRowMode ( int ) [virtual]

void QListBox::setScrollBar ( bool enable )

If enable is TRUE sets setVScrollBarMode() to AlwaysOn; otherwise sets setVScrollBarMode() to AlwaysOff.  

void QListBox::setSelected ( QListBoxItem * item, bool select ) [virtual]

If the list box is a Single selection list box and select is TRUE, setSelected() calls setCurrentItem().

If the list box is a Single selection list box, select is FALSE, setSelected() calls clearSelection().

See also multiSelection, currentItem, clearSelection(), and currentItem.  

void QListBox::setSelected ( int index, bool select )

If select is TRUE the item at position index is selected; otherwise the item is deselected.  

void QListBox::setSelectionMode ( SelectionMode ) [virtual]

void QListBox::setTopItem ( int index ) [virtual]

void QListBox::setVariableHeight ( bool ) [virtual]

void QListBox::setVariableWidth ( bool ) [virtual]

void QListBox::sort ( bool ascending = TRUE )

To compare the items, the text (QListBoxItem::text()) of the items is used.

Example: listbox/listbox.cpp.  

void QListBox::takeItem ( const QListBoxItem * item )

See also QListBox::insertItem().  

QString QListBox::text ( int index ) const

See also pixmap().  

void QListBox::toggleCurrentItem () [protected]

See also multiSelection.  

int QListBox::topItem () const

int QListBox::totalHeight () const [protected]

Returns contentsHeight().  

int QListBox::totalWidth () const [protected]

Returns contentsWidth().  

void QListBox::triggerUpdate ( bool doLayout )

void QListBox::updateItem ( int index ) [protected]

void QListBox::updateItem ( QListBoxItem * i ) [protected]

Repaints the QListBoxItem i.  

bool QListBox::variableHeight () const

bool QListBox::variableWidth () const

Property Documentation

LayoutMode columnMode

setColumnMode() sets the layout mode and adjusts the number of displayed columns. The row layout mode automatically becomes Variable, unless the column mode is Variable.

See also rowMode, rowMode, and numColumns.

Set this property's value with setColumnMode() and get this property's value with columnMode().  

uint count

Get this property's value with count().  

int currentItem

When setting this property, the highlighting is moved to the item and the list box scrolled as necessary.

If no item is current, currentItem() returns -1.

Set this property's value with setCurrentItem() and get this property's value with currentItem().  

QString currentText

This is equivalent to text(currentItem()).

Get this property's value with currentText().  

bool multiSelection

This property holds whether or not the list box is in Multi selection mode.

Consider using the QListBox::selectionMode property instead of this property.

When setting this property, Multi selection mode is used if set to TRUE and to Single selection mode if set to FALSE.

When getting this property, TRUE is returned if the list box is in Multi selection mode or Extended selection mode, and FALSE if it is in Single selection mode or NoSelection mode.

See also selectionMode.

Set this property's value with setMultiSelection() and get this property's value with isMultiSelection().  

int numColumns

This is normally 1, but can be different if QListBox::columnMode or QListBox::rowMode has been set.

See also columnMode, rowMode, and numRows.

Get this property's value with numColumns().  

int numItemsVisible

Both partially and entirely visible items are counted.

Get this property's value with numItemsVisible().  

int numRows

This is equal to the number of items in the default single-column layout, but can be different.

See also columnMode, rowMode, and numColumns.

Get this property's value with numRows().  

LayoutMode rowMode

This property is normally Variable.

setRowMode() sets the layout mode and adjusts the number of displayed rows. The column layout mode automatically becomes Variable, unless the row mode is Variable.

See also columnMode.

Set this property's value with setRowMode() and get this property's value with rowMode().  

SelectionMode selectionMode

Sets the list box's selection mode, which may be one of Single (the default), Extended, Multi or NoSelection.

See also SelectionMode.

Set this property's value with setSelectionMode() and get this property's value with selectionMode().  

int topItem

When getting this property and the listbox has multiple columns, an arbitrary item is selected and returned.

When setting this property, the list box is scrolled so the item at position index in the list is displayed in the top row of the list box.

Set this property's value with setTopItem() and get this property's value with topItem().  

bool variableHeight

When the list box has variable-height rows (the default), each row is as high as the highest item in that row. When it has same-sized rows, all rows are as high as the highest item in the list box.

See also variableWidth.

Set this property's value with setVariableHeight() and get this property's value with variableHeight().  

bool variableWidth

When the list box has variable-width columns, each column is as wide as the widest item in that column. When it has same-sized columns (the default), all columns are as wide as the widest item in the list box.

See also variableHeight.

Set this property's value with setVariableWidth() and get this property's value with variableWidth().

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