内容

• 公共类型
• 特性
• 公共函数
• 重实现公共函数
• 公共槽
• 信号
• 保护函数
• 重实现保护函数
• 详细描述

Q3ComboBox Class

The Q3ComboBox 小部件是组合按钮和弹出列表。 更多...

头：	#include <Q3ComboBox>
Since:	Qt 4.1
继承：	QWidget

• 所有成员列表，包括继承成员
• 过时成员

公共类型

enum	Policy { NoInsertion, AtTop, AtCurrent, AtBottom, AfterCurrent, BeforeCurrent }

特性

autoCompletion : bool count : const int currentItem : int currentText : QString duplicatesEnabled : bool

editable : bool insertionPolicy : Policy maxCount : int sizeLimit : int

• 58 特性继承自 QWidget
• 1 特性继承自 QObject

公共函数

	Q3ComboBox (QWidget * parent = 0, const char * name = 0)
	Q3ComboBox (bool rw , QWidget * parent = 0, const char * name = 0)
	~Q3ComboBox ()
bool	autoCompletion () const
bool	autoResize () const
void	changeItem (const QString & t , int index )
void	changeItem (const QPixmap & im , int index )
void	changeItem (const QPixmap & im , const QString & t , int index )
int	count () const
int	currentItem () const
QString	currentText () const
bool	duplicatesEnabled () const
bool	editable () const
void	hide ()
void	insertItem (const QString & t , int index = -1)
void	insertItem (const QPixmap & pixmap , int index = -1)
void	insertItem (const QPixmap & pixmap , const QString & text , int index = -1)
void	insertStrList (const char ** strings , int numStrings = -1, int index = -1)
void	insertStrList (const Q3StrList & list , int index = -1)
void	insertStrList (const Q3StrList * list , int index = -1)
void	insertStringList (const QStringList & list , int index = -1)
Policy	insertionPolicy () const
QLineEdit *	lineEdit () const
Q3ListBox *	listBox () const
int	maxCount () const
const QPixmap *	pixmap (int index ) const
virtual void	popup ()
void	removeItem (int index )
virtual void	setAutoCompletion (bool)
virtual void	setAutoResize (bool enable )
virtual void	setCurrentItem (int index )
virtual void	setCurrentText (const QString &)
void	setDuplicatesEnabled (bool enable )
void	setEditable (bool)
void	setEnabled (bool enable )
void	setFont (const QFont & font )
virtual void	setInsertionPolicy (Policy policy )
virtual void	setLineEdit (QLineEdit * edit )
virtual void	setListBox (Q3ListBox * newListBox )
virtual void	setMaxCount (int)
void	setPalette (const QPalette & palette )
virtual void	setSizeLimit (int)
virtual void	setValidator (const QValidator * v )
int	sizeLimit () const
QString	text (int index ) const
const QValidator *	validator () const

重实现公共函数

virtual QSize

sizeHint () const

• 220 公共函数继承自 QWidget
• 29 公共函数继承自 QObject
• 12 公共函数继承自 QPaintDevice

公共槽

void	clear ()
void	clearEdit ()
void	clearValidator ()
virtual void	setEditText (const QString & newText )

• 19 公共槽继承自 QWidget
• 1 公共槽继承自 QObject

信号

void	activated (int index )
void	activated (const QString & string )
void	highlighted (int index )
void	highlighted (const QString & string )
void	textChanged (const QString & string )

• 1 信号继承自 QWidget
• 1 信号继承自 QObject

保护函数

void	updateMask ()

重实现保护函数

virtual void	focusInEvent (QFocusEvent * e )
virtual void	focusOutEvent (QFocusEvent * e )
virtual void	keyPressEvent (QKeyEvent * e )
virtual void	mouseDoubleClickEvent (QMouseEvent * e )
virtual void	mouseMoveEvent (QMouseEvent *)
virtual void	mousePressEvent (QMouseEvent * e )
virtual void	mouseReleaseEvent (QMouseEvent *)
virtual void	paintEvent (QPaintEvent *)
virtual void	resizeEvent (QResizeEvent * e )
virtual void	wheelEvent (QWheelEvent * e )

• 37 保护函数继承自 QWidget
• 8 保护函数继承自 QObject
• 1 保护函数继承自 QPaintDevice

额外继承成员

• 4 static public members inherited from QWidget
• 7 静态公共成员继承自 QObject
• 1 保护槽继承自 QWidget

详细描述

The Q3ComboBox 小部件是组合按钮和弹出列表。

A combobox is a selection widget which displays the current item and can pop up a list of items. A combobox may be editable in which case the user can enter arbitrary strings.

Comboboxes provide a means of showing the user's current choice out of a list of options in a way that takes up the minimum amount of screen space.

Q3ComboBox supports three different display styles: Aqua/Motif 1.x, Motif 2.0 and Windows. In Motif 1.x, a combobox was called XmOptionMenu. In Motif 2.0, OSF introduced an improved combobox and named that XmComboBox. Q3ComboBox provides both.

Q3ComboBox provides two different constructors. The simplest constructor creates an "old-style" combobox in Motif (or Aqua) style:

Q3ComboBox *c = new Q3ComboBox(this, tr("read-only combobox"));
					

The other constructor creates a new-style combobox in Motif style, and can create both read-only and editable comboboxes:

Q3ComboBox *c1 = new Q3ComboBox(false, this, tr("read-only combobox"));
Q3ComboBox *c2 = new Q3ComboBox(true, this, tr("editable combobox"));
					

New-style comboboxes 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 with sizeLimit () 和 setMaxCount () respectively. Old-style comboboxes use a popup in Aqua and Motif style, and that popup will happily grow larger than the desktop if you put enough data into it.

The two constructors create identical-looking comboboxes in Windows style.

组合框可以包含像素图及字符串； insertItem () 和 changeItem () 函数适合被重载。对于可编辑组合框，函数 clearEdit () 的提供以清零显示字符串无需改变组合框内容。

A combobox emits two signals, activated () 和 highlighted (), when a new item has been activated (selected) or highlighted (made current). Both signals exist in two versions, one with a QString 自变量和一个带有 int argument. If the user highlights or activates a pixmap, only the int 信号被发射。每当可编辑组合框文本改变时 textChanged () 信号发射。

When the user enters a new string in an editable combobox, the widget may or may not insert it, and it can insert it in several locations. The default policy is is AtBottom 但可以改变这使用 setInsertionPolicy ().

可以将输入约束到可编辑组合框使用 QValidator ；见 setValidator ()。默认情况下，接受任何输入。

If the combobox 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 combobox is editable then it has a default focusPolicy () of StrongFocus , i.e. it will grab focus if clicked.

可以使用插入函数填充组合框， insertStringList () 和 insertItem () 例如。可以改变项采用 changeItem ()。可以移除项采用 removeItem () 和可以移除所有项采用 clear ()。返回当前项文本通过 currentText (), and the text of a numbered item is returned with text (). The current item can be set with setCurrentItem () 或 setCurrentText ()。返回组合框的项数通过 count ()；可以设置最大项数采用 setMaxCount ()。可以允许编辑使用 setEditable ()。对于可编辑组合框，可以设置自动补全使用 setAutoCompletion () 和设置用户是否可以重复添加采用 setDuplicatesEnabled ().

Depending on the style, Q3ComboBox will use a list box or a popup menu to display the list of items. See setListBox () 了解更多信息。

{GUI Design Handbook}{GUI Design Handbook: Combo Box, Drop-Down List Box}

另请参阅 QComboBox , QLineEdit ，和 QSpinBox .

成员类型文档编制

enum Q3ComboBox:: Policy

此枚举指定什么是 Q3ComboBox 应该做的，当用户键入新字符串时。

常量	值	描述
Q3ComboBox::NoInsertion	0	the string will not be inserted into the combobox.
Q3ComboBox::AtTop	1	insert the string as the first item in the combobox.
Q3ComboBox::AtCurrent	2	replace the previously selected item with the string the user has entered.
Q3ComboBox::AtBottom	3	insert the string as the last item in the combobox.
Q3ComboBox::AfterCurrent	4	insert the string after the previously selected item.
Q3ComboBox::BeforeCurrent	5	insert the string before the previously selected item.

activated () is always emitted when the string is entered.

If inserting the new string would cause the combobox 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.

特性文档编制

autoCompletion : bool

This property holds whether auto-completion is enabled.

This property can only be set for editable comboboxes, for non-editable comboboxes it has no effect. It is false by default.

访问函数：

bool	autoCompletion () const
virtual void	setAutoCompletion (bool)

count : const int

此特性保持组合框中的项数。

访问函数：

int	count () const

currentItem : int

此特性保持组合框当前项的索引。

注意， activated () 和 highlighted () signals are only emitted when the user changes the current item, not when it is changed programmatically.

访问函数：

int	currentItem () const
virtual void	setCurrentItem (int index )

currentText : QString

This property holds the text of the combobox's current item.

访问函数：

QString	currentText () const
virtual void	setCurrentText (const QString &)

duplicatesEnabled : bool

This property holds whether duplicates are allowed.

If the combobox is editable and the user enters some text in the combobox's lineedit and presses Enter (and the insertionPolicy () is not NoInsertion ), then what happens is this:

• If the text is not already in the list, the text is inserted.
• If the text is in the list and this property is true (the default), the text is inserted.
• If the text is in the list and this property is false, the text is not inserted; instead the item which has matching text becomes the current item.

This property only affects user-interaction. You can use insertItem () to insert duplicates if you wish regardless of this setting.

访问函数：

bool	duplicatesEnabled () const
void	setDuplicatesEnabled (bool enable )

editable : bool

This property holds whether the combobox is editable.

This property's default is false. Note that the combobox will be cleared if this property is set to true for a 1.x Motif style combobox. To avoid this, use setEditable() before inserting any items. Also note that the 1.x version of Motif didn't have any editable comboboxes, so the combobox will change its appearance to a 2.0 style Motif combobox is it is set to be editable.

访问函数：

bool	editable () const
void	setEditable (bool)

insertionPolicy : Policy

This property holds the position of the items inserted by the user.

The default insertion policy is AtBottom 。见 Policy .

访问函数：

Policy	insertionPolicy () const
virtual void	setInsertionPolicy (Policy policy )

maxCount : int

This property holds the maximum number of items allowed in the combobox.

访问函数：

int	maxCount () const
virtual void	setMaxCount (int)

sizeLimit : int

This property holds the maximum on-screen size of the combobox.

This property is ignored for both Motif 1.x style and non-editable comboboxes in Mac style. The default limit is ten lines. If the number of items in the combobox is or grows larger than lines, a scroll bar is added.

访问函数：

int	sizeLimit () const
virtual void	setSizeLimit (int)

成员函数文档编制

Q3ComboBox:: Q3ComboBox ( QWidget * parent = 0, const char * name = 0)

Constructs a combobox widget with parent parent called name .

This constructor creates a popup list if the program uses Motif (or Aqua) look and feel; this is compatible with Motif 1.x and Aqua.

Note: If you use this constructor to create your Q3ComboBox , then the pixmap () function will always return 0. To workaround this, use the other constructor.

Q3ComboBox:: Q3ComboBox ( bool rw , QWidget * parent = 0, const char * name = 0)

Constructs a combobox 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 combobox.

The parent and name arguments are passed on to the QWidget 构造函数。

Q3ComboBox:: ~Q3ComboBox ()

销毁组合框。

[signal] void Q3ComboBox:: activated ( int index )

This signal is emitted when a new item has been activated (selected). The index is the position of the item in the combobox.

This signal is not emitted if the item is changed programmatically, e.g. using setCurrentItem ().

注意： 信号 activated 在此类中是重载。要使用函数指针句法连接到此信号，必须在静态铸造中指定信号类型，如此范例所示：

connect(3ComboBox, static_cast<void(Q3ComboBox::*)(int)>(&Q3ComboBox::activated),
    [=](int index){ /* ... */ });
					

[signal] void Q3ComboBox:: activated (const QString & string )

这是重载函数。

This signal is emitted when a new item has been activated (selected). string is the selected string.

You can also use the activated(int) signal, but be aware that its argument is meaningful only for selected strings, not for user entered strings.

注意： 信号 activated 在此类中是重载。要使用函数指针句法连接到此信号，必须在静态铸造中指定信号类型，如此范例所示：

connect(3ComboBox, static_cast<void(Q3ComboBox::*)(const QString &)>(&Q3ComboBox::activated),
    [=](const QString &string){ /* ... */ });
					

bool Q3ComboBox:: autoResize () const

Returns true if auto-resize is enabled; otherwise returns false.

另请参阅 setAutoResize () 和 autoResize .

void Q3ComboBox:: changeItem (const QString & t , int index )

Replaces the item at position index with the text t .

void Q3ComboBox:: changeItem (const QPixmap & im , int index )

这是重载函数。

Replaces the item at position index with the pixmap im , unless the combobox is editable.

另请参阅 insertItem ().

void Q3ComboBox:: changeItem (const QPixmap & im , const QString & t , int index )

这是重载函数。

Replaces the item at position index with the pixmap im 和文本 t .

另请参阅 insertItem ().

[slot] void Q3ComboBox:: clear ()

Removes all combobox items.

[slot] void Q3ComboBox:: clearEdit ()

Clears the line edit without changing the combobox's contents. Does nothing if the combobox isn't editable.

This is particularly useful when using a combobox as a line edit with history. For example you can connect the combobox's activated () signal to clearEdit() in order to present the user with a new, empty line as soon as Enter is pressed.

另请参阅 setEditText ().

[slot] void Q3ComboBox:: clearValidator ()

This slot is equivalent to setValidator ( 0 ).

[virtual protected] void Q3ComboBox:: focusInEvent ( QFocusEvent * e )

重实现自 QWidget::focusInEvent ().

[virtual protected] void Q3ComboBox:: focusOutEvent ( QFocusEvent * e )

重实现自 QWidget::focusOutEvent ().

void Q3ComboBox:: hide ()

Hides the combobox.

另请参阅 QWidget::hide ().

[signal] void Q3ComboBox:: highlighted ( int index )

This signal is emitted when a new item has been set to be the current item. The index is the position of the item in the combobox.

This signal is not emitted if the item is changed programmatically, e.g. using setCurrentItem ().

注意： 信号 highlighted 在此类中是重载。要使用函数指针句法连接到此信号，必须在静态铸造中指定信号类型，如此范例所示：

connect(3ComboBox, static_cast<void(Q3ComboBox::*)(int)>(&Q3ComboBox::highlighted),
    [=](int index){ /* ... */ });
					

[signal] void Q3ComboBox:: highlighted (const QString & string )

这是重载函数。

This signal is emitted when a new item has been set to be the current item. string is the item's text.

You can also use the highlighted(int) signal.

注意： 信号 highlighted 在此类中是重载。要使用函数指针句法连接到此信号，必须在静态铸造中指定信号类型，如此范例所示：

connect(3ComboBox, static_cast<void(Q3ComboBox::*)(const QString &)>(&Q3ComboBox::highlighted),
    [=](const QString &string){ /* ... */ });
					

void Q3ComboBox:: insertItem (const QString & t , int index = -1)

Inserts a text item with text t , at position index . The item will be appended if index 为负。

void Q3ComboBox:: insertItem (const QPixmap & pixmap , int index = -1)

这是重载函数。

插入 pixmap item at position index . The item will be appended if index 为负。

void Q3ComboBox:: insertItem (const QPixmap & pixmap , const QString & text , int index = -1)

这是重载函数。

插入 pixmap item with additional text text 在位置 index . The item will be appended if index 为负。

void Q3ComboBox:: insertStrList (const char ** strings , int numStrings = -1, int index = -1)

Inserts the array of char * strings 在位置 index 在组合框。

The numStrings argument is the number of strings. If numStrings is -1 (default), the strings array must be terminated with 0.

范例：

static const char* items[] = { "red", "green", "blue", 0 };
combo->insertStrList( items );
					

另请参阅 insertStringList ().

void Q3ComboBox:: insertStrList (const Q3StrList & list , int index = -1)

这是重载函数。

插入 list of strings at position index 在组合框。

This is only for compatibility since it does not support Unicode strings. See insertStringList ().

void Q3ComboBox:: insertStrList (const Q3StrList * list , int index = -1)

这是重载函数。

插入 list of strings at position index 在组合框。

This is only for compatibility since it does not support Unicode strings. See insertStringList ().

void Q3ComboBox:: insertStringList (const QStringList & list , int index = -1)

插入 list of strings at position index 在组合框。

[virtual protected] void Q3ComboBox:: keyPressEvent ( QKeyEvent * e )

重实现自 QWidget::keyPressEvent ().

QLineEdit * Q3ComboBox:: lineEdit () const

Returns the line edit, or 0 if there is no line edit.

Only editable listboxes have a line editor.

另请参阅 setLineEdit ().

Q3ListBox * Q3ComboBox:: listBox () const

Returns the current list box, or 0 if there is no list box. ( Q3ComboBox can use QPopupMenu 而不是 QListBox .) Provided to match setListBox ().

另请参阅 setListBox ().

[virtual protected] void Q3ComboBox:: mouseDoubleClickEvent ( QMouseEvent * e )

重实现自 QWidget::mouseDoubleClickEvent ().

[virtual protected] void Q3ComboBox:: mouseMoveEvent ( QMouseEvent *)

重实现自 QWidget::mouseMoveEvent ().

[virtual protected] void Q3ComboBox:: mousePressEvent ( QMouseEvent * e )

重实现自 QWidget::mousePressEvent ().

[virtual protected] void Q3ComboBox:: mouseReleaseEvent ( QMouseEvent *)

重实现自 QWidget::mouseReleaseEvent ().

[virtual protected] void Q3ComboBox:: paintEvent ( QPaintEvent *)

重实现自 QWidget::paintEvent ().

const QPixmap * Q3ComboBox:: pixmap ( int index ) const

Returns the pixmap item at position index , or 0 if the item is not a pixmap.

[虚拟] void Q3ComboBox:: popup ()

Pops up the combobox popup list.

If the list is empty, no items appear.

void Q3ComboBox:: removeItem ( int index )

Removes the item at position index .

[virtual protected] void Q3ComboBox:: resizeEvent ( QResizeEvent * e )

重实现自 QWidget::resizeEvent ().

[虚拟] void Q3ComboBox:: setAutoResize ( bool enable )

若 enable is true, enable auto-resize; disable it otherwise.

另请参阅 autoResize .

[virtual slot] void Q3ComboBox:: setEditText (const QString & newText )

Sets the text in the line edit to newText without changing the combobox's contents. Does nothing if the combobox 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 combobox only when the user presses Enter.

另请参阅 clearEdit () 和 insertItem ().

void Q3ComboBox:: setEnabled ( bool enable )

Enables the combobox if enable 为 true；否则禁用它。

另请参阅 QWidget::enabled .

void Q3ComboBox:: setFont (const QFont & font )

Sets the font for both the combobox button and the combobox popup list to font .

[虚拟] void Q3ComboBox:: setLineEdit ( QLineEdit * edit )

Sets the line edit to use edit instead of the current line edit.

另请参阅 lineEdit ().

[虚拟] void Q3ComboBox:: setListBox ( Q3ListBox * newListBox )

Sets the combobox to use newListBox instead of the current list box or popup. As a side effect, it clears the combobox of its current contents.

警告： Q3ComboBox assumes that newListBox->text(n) returns non-null for 0 <= n < newListbox-> count (). This assumption is necessary because of the line edit in Q3ComboBox .

另请参阅 listBox ().

void Q3ComboBox:: setPalette (const QPalette & palette )

Sets the palette for both the combobox button and the combobox popup list to palette .

[虚拟] void Q3ComboBox:: setValidator (const QValidator * v )

Applies the validator v to the combobox so that only text which is valid according to v is accepted.

This function does nothing if the combobox is not editable.

另请参阅 validator (), clearValidator ()，和 QValidator .

[虚拟] QSize Q3ComboBox:: sizeHint () const

重实现自 QWidget::sizeHint ().

This implementation caches the size hint to avoid resizing when the contents change dynamically. To invalidate the cached value call setFont ().

QString Q3ComboBox:: text ( int index ) const

Returns the text item at position index ，或 QString::null if the item is not a string.

另请参阅 currentText ().

[signal] void Q3ComboBox:: textChanged (const QString & string )

This signal is used for editable comboboxes. It is emitted whenever the contents of the text entry field changes. string contains the new text.

[protected] void Q3ComboBox:: updateMask ()

Updates the widget mask.

另请参阅 QWidget::setMask ().

const QValidator * Q3ComboBox:: validator () const

Returns the validator which constrains editing for this combobox if there is one; otherwise returns 0.

另请参阅 setValidator (), clearValidator ()，和 QValidator .

[virtual protected] void Q3ComboBox:: wheelEvent ( QWheelEvent * e )

重实现自 QWidget::wheelEvent ().