QComboBox(3qt)QComboBox(3qt)NAMEQComboBox - Combined button and popup list
#include <qcombobox.h>
Inherits QWidget.
Public Members
QComboBox ( QWidget * parent=0, const char * name=0 )
QComboBox ( bool rw, QWidget * parent=0, const char *
name=0 )
~QComboBox ()
int count () const
void insertStringList ( const QStringList &, int index=-1
)
void insertStrList ( const QStrList &, int index=-1 )
void insertStrList ( const QStrList *, int index=-1 )
void insertStrList ( const char **, int numStrings=-1, int
index=-1 )
void insertItem ( const QString & text, int index=-1 )
void insertItem ( const QPixmap & pixmap, int index=-1 )
void insertItem ( const QPixmap & pixmap, const QString &
text, int index=-1 )
void removeItem ( int index )
void clear ()
QString currentText () const
QString text ( int index ) const
const QPixmap* pixmap ( int index ) const
void changeItem ( const QString & text, int index )
void changeItem ( const QPixmap & pixmap, int index )
void changeItem ( const QPixmap & pixmap, const QString &
text, int index )
int currentItem () const
virtual void setCurrentItem ( int index )
bool autoResize () const (obsolete)
virtual void setAutoResize ( bool ) (obsolete)
virtual void setBackgroundColor ( const QColor & )
virtual void setPalette ( const QPalette & )
virtual void setFont ( const QFont & )
virtual void setSizeLimit ( int )
int sizeLimit () const
virtual void setMaxCount ( int )
int maxCount () const
enum Policy { NoInsertion, AtTop, AtCurrent, AtBottom,
AfterCurrent, BeforeCurrent }
virtual void setInsertionPolicy ( Policy policy )
Policy insertionPolicy () const
virtual void setValidator ( const QValidator * )
const QValidator* validator () const
virtual void setListBox ( QListBox * )
QListBox* listBox () const
QLineEdit* lineEdit () const
virtual void setAutoCompletion ( bool )
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bool autoCompletion () const
void setDuplicatesEnabled ( bool enable )
bool duplicatesEnabled () const
bool editable () const
void setEditable ( bool )
Public Slots
void clearValidator ()
void clearEdit ()
virtual void setEditText ( const QString & )
Signals
void activated ( int index )
void highlighted ( int index )
void activated ( const QString & )
void highlighted ( const QString & )
void textChanged ( const QString & )
Protected Members
void popup ()
Properties
l l l l l
- - - - -
l l l l l.
Type Name READ WRITE Options
bool editable editable setEditable
int count count
QString currentText currentText
int currentItem currentItem setCurrentItem
bool autoResize autoResize setAutoResize
int sizeLimit sizeLimit setSizeLimit
int maxCount maxCount setMaxCount
Policy insertionPolicy insertionPolicy setInsertionPolicy
bool autoCompletion autoCompletion setAutoCompletion
bool duplicatesEnabled duplicatesEnabled setDuplicatesEnabled
DESCRIPTION
The QComboBox widget is a combined button and popup list.
A combo box may be defined as a selection widget which
displays the current selection, and which can pop up a
list of possible selections. Some combo boxes also allow
the user to select arbitrary strings, using a line editor.
Since combo boxes occupy little screen space and always
display the current selection, they are very well suited
to displaying and selecting modes (such as font family and
size): The user can always see what mode he/she is in, and
the majority of the screen space is available for real
work.
QComboBox supports three different appearances: Motif 1.x,
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Motif 2.0 and Windows 95. In Motif 1.x, a combo box was
called XmOptionMenu. In Motif 2.0, OSF introduced an
improved combo box and named that XmComboBox. QComboBox
provides both.
QComboBox provides two different constructors. The
simplest one creates an old-style combo box in Motif
style:
QComboBox * c = new QComboBox( this, "read-only combo" );
The other one creates a new-style combo box in Motif
style, and can create both read-only and read-write combo
boxes:
QComboBox * c1 = new QComboBox( FALSE, this, "read-only combo" );
QComboBox * c2 = new QComboBox( TRUE, this, "read-write combo" );
New-style combo boxes use a list box in both Motif and
Windows styles, and both the content size and the on-
screen size of the list box can be limited. Old-style
combo boxes use a popup in Motif style, and that popup
will happily grow larger than the desktop if you put
enough data in it.
The two constructors create identical-looking combos in
Windows style.
Combo boxes can contain pixmaps as well as texts; the
insert() and changeItem() functions are suitably
overloaded. For read-write combo boxes, the function
clearEdit() is provided, to clear the displayed string
without changing the combo box' contents.
A combo box emits two signals, activated() and
highlighted(), when a new item has been activated
(selected) or highlighted (set to current). Both signals
exist in two versions, one with a char* argument and one
with an int argument. If the user highlights or activates
a pixmap, only the int signals are emitted.
When the user enters a new string in a read-write combo,
the widget may or may not insert it, and it can insert it
in several locations. The default policy is is AtBottom,
you can change it using setInsertionPolicy().
It is possible to constrain the input to an editable combo
box using QValidator; see setValidator(). By default, all
input is accepted.
If the combo box is not editable then it has a default
focusPolicy() of TabFocus, i.e. it will not grab focus if
clicked. This differs from both Windows and Motif. If the
combo box is editable then it has a default focusPolicy()Trolltech AS 13 June 2001 3
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of StrongFocus, i.e. it will grab focus if clicked.
[Image Omitted]
(Motif 1, read-only)
[Image Omitted]
(Motif 2, read-write)
[Image Omitted]
(Motif 2, read-only)
[Image Omitted]
(Windows style)
See also QLineEdit, QListBox, QSpinBox, QRadioButton,
QButtonGroup, GUI Design Handbook: Combo Box, and GUI
Design Handbook: Drop-Down List Box.
Examples: qmag/qmag.cpp
Member Type Documentation
QComboBox::Policy
This enum type specifies what QComboBox should do with a
new string entered by the user. The following policies are
defined:
NoInsertion means not to insert the string in the combo.
AtTop means to insert the string at the top of the combo
box.
AtCurrent means to replace the previously selected item
with the typed string.
AtBottom means to insert the string at the bottom of the
combo box.
AfterCurrent means to to insert the string just after the
previously selected item.
BeforeCurrent means to to insert the string just before
the previously selected item.
activated() is always emitted, of course.
If inserting the new string would cause the combo box to
breach its content size limit, the item at the other end
of the list is deleted. The definition of "other end" is
implementation-dependent.
MEMBER FUNCTION DOCUMENTATIONTrolltech AS 13 June 2001 4
QComboBox(3qt)QComboBox(3qt)QComboBox::QComboBox ( QWidget * parent=0, const char * name=0 )
Constructs a combo box widget with a parent and a name.
This constructor creates a popup menu if the program uses
Motif look and feel; this is compatible with Motif 1.x.
QComboBox::QComboBox ( bool rw, QWidget * parent=0, const char *
name=0 )
Constructs a combo box with a maximum size and either
Motif 2.0 or Windows look and feel.
The input field can be edited if rw is TRUE, otherwise the
user may only choose one of the items in the combo box.
QComboBox::~QComboBox ()
Destructs the combo box.
void QComboBox::activated ( const QString & string ) [signal]
This signal is emitted when a new item has been activated
(selected). string is the activated string.
You can also use activated(int) signal, but be aware that
its argument is meaningful only for selected strings, not
for typed strings.
void QComboBox::activated ( int index ) [signal]
This signal is emitted when a new item has been activated
(selected). The index is the position of the item in the
popup list.
bool QComboBox::autoCompletion () const
Returns TRUE if this combo box is in auto-completion mode.
See also setAutoCompletion().
bool QComboBox::autoResize () const
This function is obsolete. It is provided to keep old
source working, and will probably be removed in a future
version of Qt. We strongly advise against using it in new
code.
Returns TRUE if auto-resizing is enabled, or FALSE if
auto-resizing is disabled.
Auto-resizing is disabled by default.
See also setAutoResize().
void QComboBox::changeItem ( const QPixmap & im, const QString &
t, int index )
Replaces the item at position index with a pixmap plus
text.
See also insertItem().
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QComboBox(3qt)QComboBox(3qt)void QComboBox::changeItem ( const QPixmap & im, int index )
Replaces the item at position index with a pixmap, unless
the combo box is writable.
See also insertItem().
void QComboBox::changeItem ( const QString & t, int index )
Replaces the item at position index with a text.
void QComboBox::clear ()
Removes all combo box items.
void QComboBox::clearEdit () [slot]
Clears the line edit without changing the combo's
contents. Does nothing if the combo isn't editable.
This is particularly handy when using a combo box as a
line edit with history. For example you can connect the
combo's activated() signal to clearEdit() in order to
present the user with a new, empty line as soon as return
is pressed.
See also setEditText().
void QComboBox::clearValidator () [slot]
This slot is equivalent to setValidator( 0 ).
int QComboBox::count () const
Returns the number of items in the combo box.
int QComboBox::currentItem () const
Returns the index of the current combo box item.
See also setCurrentItem().
QString QComboBox::currentText () const
Returns the text item being edited, or the current text
item if the combo box is not editable.
See also text().
bool QComboBox::duplicatesEnabled () const
Returns TRUE if the same text can be inserted multiple
times into the list of the combobox, else FALSE.
See also setDuplicatesEnabled();.
bool QComboBox::editable () const
Returns whether the combobox is editable or not.
See also setEditable().
bool QComboBox::eventFilter ( QObject * object, QEvent * event )
[virtual]
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Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QObject.
void QComboBox::focusInEvent ( QFocusEvent * e ) [virtual
protected]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
void QComboBox::highlighted ( const QString & string ) [signal]
This signal is emitted when a new item has been
highlighted. string is the highlighted string.
You can also use highlighted(int) signal.
void QComboBox::highlighted ( int index ) [signal]
This signal is emitted when a new item has been set to
current. The index is the position of the item in the
popup list.
void QComboBox::insertItem ( const QPixmap & pixmap, const
QString & text, int index=-1 )
Inserts a pixmap item with additional text text at
position index. The item will be appended if index is
negative.
void QComboBox::insertItem ( const QPixmap & pixmap, int index=-1
)
Inserts a pixmap item at position index. The item will be
appended if index is negative.
void QComboBox::insertItem ( const QString & t, int index=-1 )
Inserts a text item at position index. The item will be
appended if index is negative.
void QComboBox::insertStrList ( const QStrList * list, int
index=-1 )
Inserts the list of strings at the index index in the
combo box.
This is only for compatibility, as it does not support
Unicode strings. See insertStringList().
Examples: qmag/qmag.cpp
void QComboBox::insertStrList ( const char ** strings, int
numStrings=-1, int index=-1 )
Inserts the array of ASCII strings at the index index in
the combo box.
The numStrings argument is the number of strings. If
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numStrings is -1 (default), the strs array must be
terminated with 0.
Example:
static const char* items[] = { "red", "green", "blue", 0 };
combo->insertStrList( items );
void QComboBox::insertStrList ( const QStrList & list, int
index=-1 )
This is an overloaded member function, provided for
convenience. It differs from the above function only in
what argument(s) it accepts.
void QComboBox::insertStringList ( const QStringList & list, int
index=-1 )
Inserts the list of strings at the index index in the
combo box.
QComboBox::Policy QComboBox::insertionPolicy() const
Returns the current insertion policy of the combo box.
See also setInsertionPolicy().
void QComboBox::keyPressEvent ( QKeyEvent * e ) [virtual
protected]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
QLineEdit* QComboBox::lineEdit () const
Returns the line editor, or 0 if there is no line editor
currently.
Only editable listboxes have a line editor.
QListBox * QComboBox::listBox () const
Returns the current list box, or 0 if there is no list box
currently. (QComboBox can use QPopupMenu instead of
QListBox.) Provided to match setListBox().
See also setListBox().
int QComboBox::maxCount () const
Returns the current maximum size of the combo box. By
default, there is no limit, so this function returns
INT_MAX.
See also setMaxCount() and count().
void QComboBox::mouseDoubleClickEvent ( QMouseEvent * e )
[virtual protected]
Reimplemented for internal reasons; the API is not
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affected.
Reimplemented from QWidget.
void QComboBox::mouseMoveEvent ( QMouseEvent * ) [virtual
protected]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
void QComboBox::mousePressEvent ( QMouseEvent * e ) [virtual
protected]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
void QComboBox::mouseReleaseEvent ( QMouseEvent * ) [virtual
protected]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
void QComboBox::paintEvent ( QPaintEvent * ) [virtual protected]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
const QPixmap * QComboBox::pixmap ( int index ) const
Returns the pixmap item at a given index, or 0 if the item
is not a pixmap.
void QComboBox::popup () [protected]
Popups the combo box popup list.
If the list is empty, no selections appear.
void QComboBox::removeItem ( int index )
Removes the item at position index.
void QComboBox::resizeEvent ( QResizeEvent * e ) [virtual
protected]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
void QComboBox::setAutoCompletion ( bool enable ) [virtual]
Sets this combo box to offer auto-completion while the
user is editing if enable is TRUE, or not to offer auto-
completion of enable is FALSE (the default).
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The combo box uses the list of items as candidates for
completion.
Note: This will only work on editable combo boxes, so make
the combo box editable before you call this function or it
will not work.
See also autoCompletion() and setEditText().
void QComboBox::setAutoResize ( bool enable ) [virtual]
This function is obsolete. It is provided to keep old
source working, and will probably be removed in a future
version of Qt. We strongly advise against using it in new
code.
Enables auto-resizing if enable is TRUE, or disables it if
enable is FALSE.
When auto-resizing is enabled, the combo box button will
resize itself whenever the current combo box item change.
See also autoResize() and adjustSize().
void QComboBox::setBackgroundColor ( const QColor & color )
[virtual]
Reimplements QWidget::setBackgroundColor().
Sets the background color for both the combo box button
and the combo box popup list.
void QComboBox::setCurrentItem ( int index ) [virtual]
Sets the current combo box item. This is the item to be
displayed on the combo box button.
See also currentItem().
Examples: qmag/qmag.cpp
void QComboBox::setDuplicatesEnabled ( bool enable )
If the combobox is editable and the user enters some text
in the lineedit of the combobox and presses return (and
the insertionPolicy() is different from NoInsertion), the
entered text is inserted into the list of this combobox.
Now, if you set enable to TRUE here, this new text is
always inserted, else it's only inserted if it doesn't
already exist in the list. If you set enable to FALSE and
the text exists already in the list, the item which
contains the same text like which should be inserted, this
item gets the new current item.
This setting only applies when the user want's to insert a
text with pressing the return key. It does not affect
methods like insertItem() and similar.
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QComboBox(3qt)QComboBox(3qt)void QComboBox::setEditText ( const QString & newText ) [virtual
slot]
Sets the text in the embedded line edit to newText without
changing the combo's contents. Does nothing if the combo
isn't editable.
This is useful e.g. for providing a good starting point
for the user's editing and entering the change in the
combo only when the user presses enter.
See also clearEdit() and insertItem().
void QComboBox::setEditable ( bool y )
Make the input field editable, if y is TRUE. Otherwise the
user may only choose one of the items in the combo box.
See also editable().
void QComboBox::setEnabled ( bool enable ) [virtual]
Reimplemented for internal reasons; the API is not
affected.
void QComboBox::setFont ( const QFont & font ) [virtual]
Reimplements QWidget::setFont().
Sets the font for both the combo box button and the combo
box popup list.
void QComboBox::setInsertionPolicy ( Policy policy )
Sets the insertion policy of the combo box to policy.
The insertion policy governs where items typed in by the
user are inserted in the list. The possible values are
NoInsertion: Strings typed by the user aren't inserted
anywhere
AtTop: Strings typed by the user are inserted above the
top item in the list
AtCurrent: Strings typed by the user replace the last
selected item
AtBottom: Strings typed by the user are inserted at the
bottom of the list.
The default insertion policy is AtBottom.
See also insertionPolicy().
void QComboBox::setListBox ( QListBox * newListBox ) [virtual]
Sets the combo box to use newListBox instead of the
current list box or popup. As a side effect, clears the
combo box of its current contents.
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Warning: QComboBox assumes that newListBox->text(n)
returns non-null for 0 <= n < newListbox->count(). This
assumption is necessary because of the line edit in
QComboBox.
void QComboBox::setMaxCount ( int count ) [virtual]
Sets the maximum number of items the combo box can hold to
count.
If count is smaller than the current number of items, the
list is truncated at the end. There is no limit by
default.
See also maxCount() and count().
void QComboBox::setPalette ( const QPalette & palette ) [virtual]
Reimplements QWidget::setPalette().
Sets the palette for both the combo box button and the
combo box popup list.
void QComboBox::setSizeLimit ( int lines ) [virtual]
Sets the maximum on-screen size of the combo box to lines.
This is disregarded in Motif 1.x style. The default limit
is ten lines.
If the number of items in the combo box is/grows larger
than lines, a list box is added.
See also sizeLimit(), count() and setMaxCount().
void QComboBox::setValidator ( const QValidator * v ) [virtual]
Sets this combo box to be editable only as allowed by v.
This function does nothing if the combo is not editable.
See also validator(), clearValidator() and QValidator.
QSize QComboBox::sizeHint () const [virtual]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
int QComboBox::sizeLimit () const
Returns the current maximum on-screen size of the combo
box. The default is ten lines.
See also setSizeLimit(), count() and maxCount().
QSizePolicy QComboBox::sizePolicy () const [virtual]
Reimplemented for internal reasons; the API is not
affected.
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QComboBox(3qt)QComboBox(3qt)void QComboBox::styleChange ( QStyle & s ) [virtual protected]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
QString QComboBox::text ( int index ) const
Returns the text item at a given index, or null string if
the item is not a string.
See also currentText().
void QComboBox::textChanged ( const QString & string ) [signal]
This signal is useful for editable comboboxes. It is
emitted whenever the contents of the text entry field
changes.
void QComboBox::updateMask () [virtual protected]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
const QValidator * QComboBox::validator () const
Returns the validator which constrains editing for this
combo box if there is any, or else 0.
See also setValidator(), clearValidator() and QValidator.
SEE ALSO
http://doc.trolltech.com/qcombobox.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2001 Trolltech AS,
http://www.trolltech.com. See the license file included
in the distribution for a complete license statement.
AUTHOR
Generated automatically from the source code.
BUGS
If you find a bug in Qt, please report it as described in
http://doc.trolltech.com/bughowto.html. Good bug reports
make our job much simpler. Thank you.
In case of content or formattting problems with this
manual page, please report them to qt-bugs@trolltech.com.
Please include the name of the manual page (qcombobox.3qt)
and the Qt version (2.3.1).
Trolltech AS 13 June 2001 13
