本帖子已过去太久远了，不再提供回复功能。QLineEdit Class
widget is a one-line text editor.
Header: #include &QLineEdit&
Public Types
{ Normal, NoEcho, Password, PasswordEchoOnEdit }
Properties
: const bool
: Qt::Alignment
: Qt::CursorMoveStyle
: const QString
: EchoMode
: const bool
: const bool
: const QString
: const bool
58 properties inherited from
1 property inherited from
Public Functions
(QWidget * parent = 0)
(const QString & contents, QWidget * parent = 0)
Qt::Alignment () const
QCompleter * () const
QMenu * ()
void (bool mark, int steps = 1)
void (bool mark, int steps = 1)
Qt::CursorMoveStyle () const
int () const
int (const QPoint & pos)
void (bool mark)
void (bool mark)
QString () const
bool () const
EchoMode () const
void (bool mark)
void (int * left, int * top, int * right, int * bottom) const
bool () const
bool () const
bool () const
void (bool mark)
QString () const
void (const QString & newText)
bool () const
bool () const
bool () const
bool () const
int () const
QString () const
QString () const
int () const
void (Qt::Alignment flag)
void (QCompleter * c)
void (Qt::CursorMoveStyle style)
void (int)
void (bool b)
void (EchoMode)
void (bool)
void (const QString & inputMask)
void (int)
void (bool)
void (const QString &)
void (bool)
void (int start, int length)
void (int left, int top, int right, int bottom)
void (const QMargins & margins)
void (const QValidator * v)
QString () const
QMargins () const
const QValidator * () const
Reimplemented Public Functions
virtual bool (QEvent * e)
virtual QVariant (Qt::InputMethodQuery property) const
virtual QSize () const
virtual QSize () const
220 public functions inherited from
29 public functions inherited from
12 public functions inherited from
Public Slots
void () const
void (const QString &)
19 public slots inherited from
1 public slot inherited from
void (int old, int new)
void (const QString & text)
void (const QString & text)
1 signal inherited from
1 signal inherited from
Protected Functions
QRect () const
void (QStyleOptionFrame * option) const
Reimplemented Protected Functions
virtual void (QEvent * ev)
virtual void (QContextMenuEvent * event)
virtual void (QDragEnterEvent * e)
virtual void (QDragLeaveEvent * e)
virtual void (QDragMoveEvent * e)
virtual void (QDropEvent * e)
virtual void (QFocusEvent * e)
virtual void (QFocusEvent * e)
virtual void (QInputMethodEvent * e)
virtual void (QKeyEvent * event)
virtual void (QMouseEvent * e)
virtual void (QMouseEvent * e)
virtual void (QMouseEvent * e)
virtual void (QMouseEvent * e)
virtual void (QPaintEvent *)
37 protected functions inherited from
8 protected functions inherited from
1 protected function inherited from
Additional Inherited Members
4 static public members inherited from
7 static public members inherited from
1 protected slot inherited from
Detailed Description
widget is a one-line text editor.
A line edit allows the user to enter and edit a single line of plain text with a useful collection of editing functions, including undo and redo, cut and paste, and drag and drop.
By changing the () of a line edit, it can also be used as a "write-only" field, for inputs such as passwords.
The length of the text can be constrained to (). The text can be arbitrarily constrained using a () or an (), or both. When switching between a validator and an input mask on the same line edit, it is best to clear the validator or input mask to prevent undefined behavior.
A related class is
which allows multi-line, rich text editing.
You can change the text with () or (). The text is retrieved with (); the displayed text (which may be different, see ) is retrieved with (). Text can be selected with () or (), and the selection can be (), ()ied and ()d. The text can be aligned with ().
When the text changes the () when the text changes other than by calling () the () when the cursor is moved the () and when the Return or Enter key is pressed the () signal is emitted.
When editing is finished, either because the line edit lost focus or Return/Enter is pressed the () signal is emitted.
Note that if there is a validator set on the line edit, the ()/() signals will only be emitted if the validator returns .
By default, QLineEdits have a frame as specified by the Windows and M you can turn it off by calling (false).
The default key bindings are described below. The line edit also provides a context menu (usually invoked by a right mouse click) that presents some of these editing options.
KeypressAction
Left ArrowMoves the cursor one character to the left.
Shift+Left ArrowMoves and selects text one character to the left.
Right ArrowMoves the cursor one character to the right.
Shift+Right ArrowMoves and selects text one character to the right.
HomeMoves the cursor to the beginning of the line.
EndMoves the cursor to the end of the line.
BackspaceDeletes the character to the left of the cursor.
Ctrl+BackspaceDeletes the word to the left of the cursor.
DeleteDeletes the character to the right of the cursor.
Ctrl+DeleteDeletes the word to the right of the cursor.
Ctrl+ASelect all.
Ctrl+CCopies the selected text to the clipboard.
Ctrl+InsertCopies the selected text to the clipboard.
Ctrl+KDeletes to the end of the line.
Ctrl+VPastes the clipboard text into line edit.
Shift+InsertPastes the clipboard text into line edit.
Ctrl+XDeletes the selected text and copies it to the clipboard.
Shift+DeleteDeletes the selected text and copies it to the clipboard.
Ctrl+ZUndoes the last operation.
Ctrl+YRedoes the last undone operation.
Any other key sequence that represents a valid character, will cause the character to be inserted into the line edit.
A line edit shown in the .
A line edit shown in the .
A line edit shown in the .
See also , , , , and .
Member Type Documentation
enum QLineEdit::EchoMode
This enum type describes how a line edit should display its contents.
ConstantValueDescription
QLineEdit::Normal0Display characters as they are entered. This is the default.
QLineEdit::NoEcho1Do not display anything. This may be appropriate for passwords where even the length of the password should be kept secret.
QLineEdit::Password2Display asterisks instead of the characters actually entered.
QLineEdit::PasswordEchoOnEdit3Display characters as they are entered while editing otherwise display asterisks.
See also () and ().
Property Documentation
acceptableInput : const bool
This property holds whether the input satisfies the inputMask and the validator.
By default, this property is true.
Access functions:
bool hasAcceptableInput() const
See also () and ().
alignment : Qt::Alignment
This property holds the alignment of the line edit.
Both horizontal and vertical alignment is allowed here,
will map to .
By default, this property contains a combination of
Access functions:
Qt::Alignment alignment() const
void setAlignment(Qt::Alignment flag)
See also .
cursorMoveStyle : Qt::CursorMoveStyle
This property holds the movement style of cursor in this line edit.
When this property is set to , the line edit will use visual movement style. Pressing the left arrow key will always cause the cursor to move left, regardless of the text's writing direction. The same behavior applies to right arrow key.
When the property is
(the default), within a LTR text block, increase cursor position when pressing left arrow key, decrease cursor position when pressing the right arrow key. If the text block is right to left, the opposite behavior applies.
This property was introduced in
Access functions:
Qt::CursorMoveStyle cursorMoveStyle() const
void setCursorMoveStyle(Qt::CursorMoveStyle style)
cursorPosition : int
This property holds the current cursor position for this line edit.
Setting the cursor position causes a repaint when appropriate.
By default, this property contains a value of 0.
Access functions:
int cursorPosition() const
void setCursorPosition(int)
displayText : const
This property holds the displayed text.
this returns the same as (); if
it returns a string of asterisks ().length() characters long, e.g. "******"; if
returns an empty string, "".
By default, this property contains an empty string.
Access functions:
QString displayText() const
See also (), (), and .
dragEnabled : bool
This property holds whether the lineedit starts a drag if the user presses and moves the mouse on some selected text.
Dragging is disabled by default.
Access functions:
bool dragEnabled() const
void setDragEnabled(bool b)
echoMode :
This property holds the line edit's echo mode.
The echo mode determines how the text entered in the line edit is displayed (or echoed) to the user.
The most common setting is , in which the text entered by the user is displayed verbatim, but
also supports modes that allow the entered text to be suppressed or obscured: these include ,
The widget's display and the ability to copy or drag the text is affected by this setting.
By default, this property is set to .
Access functions:
EchoMode echoMode() const
void setEchoMode(EchoMode)
frame : bool
This property holds whether the line edit draws itself with a frame.
If enabled (the default) the line edit draws itself inside a frame, otherwise the line edit draws itself without any frame.
Access functions:
bool hasFrame() const
void setFrame(bool)
hasSelectedText : const bool
This property holds whether there is any text selected.
hasSelectedText() returns true if some or all of the text has been
otherwise returns false.
By default, this property is false.
Access functions:
bool hasSelectedText() const
See also ().
inputMask :
This property holds the validation input mask.
If no mask is set, inputMask() returns an empty string.
Sets the 's validation mask. Validators can be used instead of, or in co see ().
Unset the mask and return to normal
operation by passing an empty string ("") or just calling setInputMask() with no arguments.
The table below shows the characters that can be used in an input mask. A space character, the default character for a blank, is needed for cases where a character is permitted but not required.
CharacterMeaning
AASCII alphabetic character required. A-Z, a-z.
aASCII alphabetic character permitted but not required.
NASCII alphanumeric character required. A-Z, a-z, 0-9.
nASCII alphanumeric character permitted but not required.
XAny character required.
xAny character permitted but not required.
9ASCII digit required. 0-9.
0ASCII digit permitted but not required.
DASCII digit required. 1-9.
dASCII digit permitted but not required (1-9).
#ASCII digit or plus/minus sign permitted but not required.
HHexadecimal character required. A-F, a-f, 0-9.
hHexadecimal character permitted but not required.
BBinary character required. 0-1.
bBinary character permitted but not required.
&All following alphabetic characters are uppercased.
&All following alphabetic characters are lowercased.
!Switch off case conversion.
\Use \ to escape the special characters listed above to use them as separators.
The mask consists of a string of mask characters and separators, optionally followed by a semicolon and the character used for blanks. The blank characters are always removed from the text after editing.
000.000.000.000;_IP blanks are _.
HH:HH:HH:HH:HH:HH;_MAC address
ISO D blanks are space
&AAAAA-AAAAA-AAAAA-AAAAA-AAAAA;#L blanks are - and all (alphabetic) characters are converted to uppercase.
To get range control (e.g., for an IP address) use masks together with .
Access functions:
QString inputMask() const
void setInputMask(const QString & inputMask)
See also .
maxLength : int
This property holds the maximum permitted length of the text.
If the text is too long, it is truncated at the limit.
If truncation occurs any selected text will be unselected, the cursor position is set to 0 and the first part of the string is shown.
If the line edit has an input mask, the mask defines the maximum string length.
By default, this property contains a value of 32767.
Access functions:
int maxLength() const
void setMaxLength(int)
See also .
modified : bool
This property holds whether the line edit's contents has been modified by the user.
The modified fl it has a default value of false and is changed to true whenever the user changes the line edit's contents.
This is useful for things that need to provide a default value but do not start out knowing what the default should be (perhaps it depends on other fields on the form). Start the line edit without the best default, and when the default is known, if modified() returns false (the user hasn't entered any text), insert the default value.
Calling () resets the modified flag to false.
Access functions:
bool isModified() const
void setModified(bool)
placeholderText :
This property holds the line edit's placeholder text.
Setting this property makes the line edit display a grayed-out placeholder text as long as the () is empty and the widget doesn't have focus.
By default, this property contains an empty string.
This property was introduced in
Access functions:
QString placeholderText() const
void setPlaceholderText(const QString &)
See also ().
readOnly : bool
This property holds whether the line edit is read only.
In read-only mode, the user can still copy the text to the clipboard, or drag and drop the text (if () is ), but cannot edit it.
does not show a cursor in read-only mode.
By default, this property is false.
Access functions:
bool isReadOnly() const
void setReadOnly(bool)
See also ().
redoAvailable : const bool
This property holds whether redo is available.
Redo becomes available once the user has performed one or more undo operations on text in the line edit.
By default, this property is false.
Access functions:
bool isRedoAvailable() const
selectedText : const
This property holds the selected text.
If there is no selected text this property's value is an empty string.
By default, this property contains an empty string.
Access functions:
QString selectedText() const
See also ().
This property holds the line edit's text.
Setting this property clears the selection, clears the undo/redo history, moves the cursor to the end of the line and resets the
property to false. The text is not validated when inserted with setText().
The text is truncated to () length.
By default, this property contains an empty string.
Access functions:
QString text() const
void setText(const QString &)
Notifier signal:
void textChanged(const QString & text)
See also () and ().
undoAvailable : const bool
This property holds whether undo is available.
Undo becomes available once the user has modified the text in the line edit.
By default, this property is false.
Access functions:
bool isUndoAvailable() const
Member Function Documentation
QLineEdit::QLineEdit( * parent = 0)
Constructs a line edit with no text.
The maximum text length is set to 32767 characters.
The parent argument is sent to the
constructor.
See also () and ().
QLineEdit::QLineEdit(const
& contents,
* parent = 0)
Constructs a line edit containing the text contents.
The cursor position is set to the end of the line and the maximum text length to 32767 characters.
The parent and argument is sent to the
constructor.
See also () and ().
QLineEdit::~QLineEdit()
Destroys the line edit.
void QLineEdit::backspace()
If no text is selected, deletes the character to the left of the text cursor and moves the cursor one position to the left. If any text is selected, the cursor is moved to the beginning of the selected text and the selected text is deleted.
See also ().
[virtual protected] void QLineEdit::changeEvent( * ev)
Reimplemented from ().
[slot] void QLineEdit::clear()
Clears the contents of the line edit.
See also () and ().
* QLineEdit::completer() const
Returns the current
that provides completions.
This function was introduced in
See also ().
[virtual protected] void QLineEdit::contextMenuEvent( * event)
Reimplemented from ().
Shows the standard context menu created with ().
If you do not want the line edit to have a context menu, you can set its
to . If you want to customize the context menu, reimplement this function. If you want to extend the standard context menu, reimplement this function, call () and extend the menu returned.
void LineEdit::contextMenuEvent( *event)
*menu = createStandardContextMenu();
menu-&addAction(tr("My Menu Item"));
menu-&exec(event-&globalPos());
The event parameter is used to obtain the position where the mouse cursor was when the event was generated.
See also ().
[slot] void QLineEdit::copy() const
Copies the selected text to the clipboard, if there is any, and if () is .
See also () and ().
* QLineEdit::createStandardContextMenu()
This function creates the standard context menu which is shown when the user clicks on the line edit with the right mouse button. It is called from the default () handler. The popup menu's ownership is transferred to the caller.
void QLineEdit::cursorBackward(bool mark, int steps = 1)
Moves the cursor back steps characters. If mark is true each character moved over is ad if mark is false the selection is cleared.
See also ().
void QLineEdit::cursorForward(bool mark, int steps = 1)
Moves the cursor forward steps characters. If mark is true each character moved over is ad if mark is false the selection is cleared.
See also ().
int QLineEdit::cursorPositionAt(const
Returns the cursor position under the point pos.
[signal] void QLineEdit::cursorPositionChanged(int old, int new)
This signal is emitted whenever the cursor moves. The previous position is given by old, and the new position by new.
See also () and ().
[protected]
QLineEdit::cursorRect() const
Returns a rectangle that includes the lineedit cursor.
This function was introduced in
void QLineEdit::cursorWordBackward(bool mark)
Moves the cursor one word backward. If mark is true, the word is also selected.
See also ().
void QLineEdit::cursorWordForward(bool mark)
Moves the cursor one word forward. If mark is true, the word is also selected.
See also ().
[slot] void QLineEdit::cut()
Copies the selected text to the clipboard and deletes it, if there is any, and if () is .
If the current validator disallows deleting the selected text, cut() will copy without deleting.
See also (), (), and ().
void QLineEdit::del()
If no text is selected, deletes the character to the right of the text cursor. If any text is selected, the cursor is moved to the beginning of the selected text and the selected text is deleted.
See also ().
void QLineEdit::deselect()
Deselects any selected text.
See also () and ().
[virtual protected] void QLineEdit::dragEnterEvent( * e)
Reimplemented from ().
[virtual protected] void QLineEdit::dragLeaveEvent( * e)
Reimplemented from ().
[virtual protected] void QLineEdit::dragMoveEvent( * e)
Reimplemented from ().
[virtual protected] void QLineEdit::dropEvent( * e)
Reimplemented from ().
[signal] void QLineEdit::editingFinished()
This signal is emitted when the Return or Enter key is pressed or the line edit loses focus. Note that if there is a () or () set on the line edit and enter/return is pressed, the editingFinished() signal will only be emitted if the input follows the () and the () returns .
void QLineEdit::end(bool mark)
Moves the text cursor to the end of the line unless it is already there. If mark is true, text is selected towar otherwise, any selected text is unselected if the cursor is moved.
See also ().
[virtual] bool QLineEdit::event( * e)
Reimplemented from ().
[virtual protected] void QLineEdit::focusInEvent( * e)
Reimplemented from ().
[virtual protected] void QLineEdit::focusOutEvent( * e)
Reimplemented from ().
void QLineEdit::getTextMargins(int * left, int * top, int * right, int * bottom) const
Returns the widget's text margins for left, top, right, and bottom.
This function was introduced in
See also ().
void QLineEdit::home(bool mark)
Moves the text cursor to the beginning of the line unless it is already there. If mark is true, text is selected toward otherwise, any selected text is unselected if the cursor is moved.
See also ().
[protected] void QLineEdit::initStyleOption( * option) const
Initialize option with the values from this . This method is useful for subclasses when they need a
or , but don't want to fill in all the information themselves. This function will check the version of the
and fill in the additional values for a .
See also ().
[virtual protected] void QLineEdit::inputMethodEvent( * e)
Reimplemented from ().
QLineEdit::inputMethodQuery(Qt::InputMethodQuery property) const
Reimplemented from ().
void QLineEdit::insert(const
& newText)
Deletes any selected text, inserts newText, and validates the result. If it is valid, it sets it as the new contents of the line edit.
See also () and ().
[virtual protected] void QLineEdit::keyPressEvent( * event)
Reimplemented from ().
Converts the given key press event into a line edit action.
If Return or Enter is pressed and the current text is valid (or can be
by the validator), the signal () is emitted.
The default key bindings are listed in the class's detailed description.
QLineEdit::minimumSizeHint() const
Reimplemented from ().
Returns a minimum size for the line edit.
The width returned is enough for at least one character.
[virtual protected] void QLineEdit::mouseDoubleClickEvent( * e)
Reimplemented from ().
[virtual protected] void QLineEdit::mouseMoveEvent( * e)
Reimplemented from ().
[virtual protected] void QLineEdit::mousePressEvent( * e)
Reimplemented from ().
[virtual protected] void QLineEdit::mouseReleaseEvent( * e)
Reimplemented from ().
[virtual protected] void QLineEdit::paintEvent( *)
Reimplemented from ().
[slot] void QLineEdit::paste()
Inserts the clipboard's text at the cursor position, deleting any selected text, providing the line edit is not .
If the end result would not be acceptable to the current , nothing happens.
See also () and ().
[slot] void QLineEdit::redo()
Redoes the last operation if redo is .
[signal] void QLineEdit::returnPressed()
This signal is emitted when the Return or Enter key is pressed. Note that if there is a () or () set on the line edit, the returnPressed() signal will only be emitted if the input follows the () and the () returns .
[slot] void QLineEdit::selectAll()
Selects all the text (i.e. highlights it) and moves the cursor to the end. This is useful when a default value has been inserted because if the user types before clicking on the widget, the selected text will be deleted.
See also () and ().
[signal] void QLineEdit::selectionChanged()
This signal is emitted whenever the selection changes.
See also () and ().
int QLineEdit::selectionStart() const
selectionStart() returns the index of the first selected character in the line edit or -1 if no text is selected.
See also ().
void QLineEdit::setCompleter( * c)
Sets this line edit to provide auto completions from the completer, c. The completion mode is set using ().
or , you need to ensure that the model provided to
contains valid entries. You can use the
to ensure that the 's model contains only valid entries.
If c == 0, setCompleter() removes the current completer, effectively disabling auto completion.
This function was introduced in
See also () and .
void QLineEdit::setSelection(int start, int length)
Selects text from position start and for length characters. Negative lengths are allowed.
See also (), (), and ().
void QLineEdit::setTextMargins(int left, int top, int right, int bottom)
Sets the margins around the text inside the frame to have the sizes left, top, right, and bottom.
See also ().
This function was introduced in
See also ().
void QLineEdit::setTextMargins(const
& margins)
Sets the margins around the text inside the frame.
See also ().
This function was introduced in
void QLineEdit::setValidator(const
Sets this line edit to only accept input that the validator, v, will accept. This allows you to place any arbitrary constraints on the text which may be entered.
If v == 0, setValidator() removes the current input validator. The initial setting is to have no input validator (i.e. any input is accepted up to ()).
See also (), , , and .
QLineEdit::sizeHint() const
Reimplemented from ().
Returns a recommended size for the widget.
The width returned, in pixels, is usually enough for about 15 to 20 characters.
[signal] void QLineEdit::textEdited(const
This signal is emitted whenever the text is edited. The text argument is the new text.
Unlike (), this signal is not emitted when the text is changed programmatically, for example, by calling ().
QLineEdit::textMargins() const
Returns the widget's text margins.
This function was introduced in
See also ().
[slot] void QLineEdit::undo()
Undoes the last operation if undo is . Deselects any current selection, and updates the selection start to the current cursor position.
* QLineEdit::validator() const
Returns a pointer to the current input validator, or 0 if no validator has been set.
See also ().
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