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QLineEdit Class Reference

The QLineEdit widget is a one-line text editor. More...

#include <qlineedit.h>

Inherits QFrame.

List of all member functions.

Public Members

Public Slots

Signals

Properties

Protected Members


Detailed Description

The QLineEdit 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 echoMode() of a line edit, it can also be used as a "write-only" field, for inputs such as passwords.

The length of the field can be constrained to a maxLength(), or the value can be arbitrarily constrained by setting a validator().

A closely related class is QTextEdit which allows multi-line, rich-text editing.

The default QLineEdit object has its own frame as specified by the Windows/Motif style guides; you can turn off the frame by calling setFrame( FALSE ).

The default key bindings are described in keyPressEvent(). A right-mouse-button menu presents a number of the editing commands to the user.

See also QTextEdit, QLabel, QComboBox, GUI Design Handbook: Field, Entry, and GUI Design Handbook: Field, Required..


Member Type Documentation

QLineEdit::EchoMode

This enum type describes how QLineEdit displays its contents. The defined values are:

See also echoMode and echoMode.


Member Function Documentation

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

Constructs a line edit with no text.

The maximum text length is set to 32767 characters.

The parent and name arguments are sent to the QWidget constructor.

See also text and maxLength.

QLineEdit::QLineEdit ( const QString & contents, QWidget * parent, const char * name = 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 name arguments are sent to the QWidget constructor.

See also text and maxLength.

QLineEdit::~QLineEdit ()

Destroys the line edit.

int QLineEdit::alignment () const

Returns the alignment of the line edit. See the "alignment" property for details.

void QLineEdit::backspace ()

Deletes the character to the left of the text cursor and moves the cursor one position to the left. If a text has been marked by the user (e.g., by clicking and dragging), the cursor will be put at the beginning of the marked text and the marked text will be removed.

See also del().

void QLineEdit::clear () [virtual slot]

Syntactic sugar for setText( "" ), provided to match no-argument signals.

void QLineEdit::clearValidator () [virtual slot]

This slot is equivalent to setValidator( 0 ).

void QLineEdit::copy () const [virtual slot]

Copies the marked text to the clipboard, if there is any and if echoMode() is Normal.

See also cut() and paste().

QPopupMenu * QLineEdit::createPopupMenu () [virtual protected]

This function is called to create the popup menu which is shown when the user clicks on the lineedit with the right mouse button. If you want to create a custom popup menu, reimplement this function and return the created popup menu. The ownership is transferred to the caller.

void QLineEdit::cursorBackward ( bool mark, int steps = 1 )

Moves the cursor back one or more characters.

See also cursorForward().

void QLineEdit::cursorForward ( bool mark, int steps = 1 )

Moves the cursor forward one or more characters.

See also cursorBackward().

void QLineEdit::cursorLeft ( bool mark, int steps = 1 )

This function is obsolete. It is provided to keep old source working. We strongly advise against using it in new code.

For compatibilty with older applications only. Use cursorBackward instead.

See also cursorBackward().

int QLineEdit::cursorPosition () const

Returns the current cursor position for this line edit. See the "cursorPosition" property for details.

void QLineEdit::cursorRight ( bool mark, int steps = 1 )

This function is obsolete. It is provided to keep old source working. We strongly advise against using it in new code.

Use cursorForward instead.

See also cursorForward().

void QLineEdit::cursorWordBackward ( bool mark )

Moves the cursor one word backward. If mark is TRUE, the text is marked.

See also cursorWordForward().

void QLineEdit::cursorWordForward ( bool mark )

Moves the cursor one word forward. If mark is TRUE, the text is marked.

See also cursorWordBackward().

void QLineEdit::cut () [virtual slot]

Copies the marked text to the clipboard and deletes it, if there is any.

If the current validator disallows deleting the marked text, cut() will copy it but not delete it.

See also copy() and paste().

void QLineEdit::del ()

Deletes the character on the right side of the text cursor. If a text has been marked by the user (e.g., by clicking and dragging), the cursor will be put at the beginning of the marked text and the marked text will be removed.

See also backspace().

void QLineEdit::deselect () [virtual slot]

Deselects all text (i.e., removes marking) and leaves the cursor at the current position.

See also setSelection() and selectAll().

QString QLineEdit::displayText () const

Returns the text that is displayed. See the "displayText" property for details.

EchoMode QLineEdit::echoMode () const

Returns the echo mode of the line edit. See the "echoMode" property for details.

bool QLineEdit::edited () const

Returns the edited flag of the line edit. See the "edited" property for details.

void QLineEdit::end ( bool mark )

Moves the text cursor to the end of the line. If mark is TRUE, text is marked towards the last position; if not, any marked text is unmarked if the cursor is moved.

See also home().

bool QLineEdit::frame () const

Returns TRUE if the line edit draws itself with a frame; otherwise returns FALSE. See the "frame" property for details.

bool QLineEdit::getSelection ( int * start, int * end )

This function sets start to the position in the text where the selection starts and end to the selection end and returns TRUE, if there is a selection. Else it returns FALSE:

bool QLineEdit::hasMarkedText () const

Returns TRUE if part of the text has been selected by the user (e.g., by clicking and dragging); otherwise returns FALSE. See the "hasMarkedText" property for details.

void QLineEdit::home ( bool mark )

Moves the text cursor to the beginning of the line. If mark is TRUE, text is marked towards the first position; if not, any marked text is unmarked if the cursor is moved.

See also end().

void QLineEdit::insert ( const QString & newText ) [virtual slot]

Removes any selected text, inserts newText, and validates the result. If it is valid, it sets it as the new contents of the line edit.

bool QLineEdit::isReadOnly () const

Returns TRUE if the line edit is read only; otherwise returns FALSE. See the "readOnly" property for details.

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

Converts a key press into a line edit action.

If Return or Enter is pressed and the current text is valid (or can be made valid by the validator), the signal returnPressed is emitted.

The default key bindings are:

In addition, the following key bindings are used on Windows:

All other keys with valid ASCII codes insert themselves into the line.

Reimplemented from QWidget.

QString QLineEdit::markedText () const

Returns the text selected by the user (e.g., by clicking and dragging), or QString::null if no text is selected. See the "markedText" property for details.

int QLineEdit::maxLength () const

Returns the maximum permitted length of the text in the editor. See the "maxLength" property for details.

QSize QLineEdit::minimumSizeHint () const [virtual]

Returns a minimum size for the line edit.

The width returned is enough for one character at least.

Reimplemented from QWidget.

void QLineEdit::paste () [virtual slot]

Inserts the clipboard's text at the cursor position, deleting any previous marked text.

If the end result is not acceptable for the current validator, nothing happens.

See also copy() and cut().

void QLineEdit::redo () [virtual slot]

Redoes the last operation

void QLineEdit::repaintArea ( int from, int to ) [protected]

This function is obsolete. It is provided to keep old source working. We strongly advise against using it in new code.

Repaints all characters from from to to. If cursorPos is between from and to, ensures that cursorPos is visible.

void QLineEdit::returnPressed () [signal]

This signal is emitted when the Return or Enter key is pressed.

Example: popup/popup.cpp.

void QLineEdit::selectAll () [virtual slot]

Selects all text (i.e., marks 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 erased.

See also setSelection() and deselect().

void QLineEdit::setCursorPosition ( int ) [virtual slot]

Sets the current cursor position for this line edit. See the "cursorPosition" property for details.

void QLineEdit::setEchoMode ( EchoMode ) [virtual slot]

Sets the echo mode of the line edit. See the "echoMode" property for details.

void QLineEdit::setEdited ( bool )

Sets the edited flag of the line edit. See the "edited" property for details.

void QLineEdit::setFrame ( bool ) [virtual slot]

Sets whether the line edit draws itself with a frame. See the "frame" property for details.

void QLineEdit::setMaxLength ( int ) [virtual slot]

Sets the maximum permitted length of the text in the editor. See the "maxLength" property for details.

void QLineEdit::setReadOnly ( bool ) [virtual slot]

Sets whether the line edit is read only. See the "readOnly" property for details.

void QLineEdit::setSelection ( int start, int length ) [virtual slot]

Sets the marked area of this line edit to start at start and be length characters long.

See also deselect() and selectAll().

void QLineEdit::setText ( const QString & ) [virtual slot]

Sets the text in the line. See the "text" property for details.

void QLineEdit::setValidator ( const QValidator * v ) [virtual slot]

Sets this line edit to accept input only as accepted by v, allowing arbitrary constraints on the text which the user can edit.

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 maxLength()).

See also validator() and QValidator.

Examples: lineedits/lineedits.cpp and wizard/wizard.cpp.

QSize QLineEdit::sizeHint () const [virtual]

Returns a recommended size for the widget.

The width returned is enough for a few characters, typically 15 to 20 pixels.

Example: addressbook/centralwidget.cpp.

Reimplemented from QFrame.

QString QLineEdit::text () const

Returns the text in the line. See the "text" property for details.

void QLineEdit::textChanged ( const QString & ) [signal]

This signal is emitted every time the text changes. The argument is the new text.

Examples: wizard/wizard.cpp and xform/xform.cpp.

void QLineEdit::undo () [virtual slot]

Undoes the last operation

bool QLineEdit::validateAndSet ( const QString & newText, int newPos, int newMarkAnchor, int newMarkDrag )

Validates and perhaps sets this line edit to contain newText with the cursor at position newPos, with marked text from newMarkAnchor to newMarkDrag. Returns TRUE if it changes the line edit and FALSE if it doesn't.

Linebreaks in newText are converted to spaces, and it is truncated to maxLength() before testing its validity.

Repaints and emits textChanged() if appropriate.

const QValidator * QLineEdit::validator () const

Returns a pointer to the current input validator, or 0 if no validator has been set.

See also setValidator().

Example: wizard/wizard.cpp.


Property Documentation

Alignment alignment

This property holds the alignment of the line edit.

Possible Values are Qt::AlignAuto, Qt::AlignLeft, Qt::AlignRight and Qt::AlignHCenter.

Attempting to set the alignment to an illegal flag combination does nothing.

Set this property's value with setAlignment() and get this property's value with alignment().

See also Qt::AlignmentFlags.

int cursorPosition

This property holds the current cursor position for this line edit.

Setting the cursor position causes a repaint when appropriate.

Set this property's value with setCursorPosition() and get this property's value with cursorPosition().

QString displayText

This property holds the text that is displayed.

This is normally the same as text(), but can be a string like "*****" if EchoMode is Password or "" if it is NoEcho.

Get this property's value with displayText().

See also echoMode, text and EchoMode.

EchoMode echoMode

This property holds the echo mode of the line edit.

The initial setting is Normal, but QLineEdit also supports NoEcho and Password.

The widget's display and the ability to copy or drag the text is affected by this setting.

Set this property's value with setEchoMode() and get this property's value with echoMode().

See also EchoMode and displayText.

bool edited

This property holds the edited flag of the line edit.

The edited flag is never read by QLineEdit; it has a default value of FALSE and is changed to TRUE whenever the user changes the line edits contents.

This is useful for things that need to provide a default value but cannot find the default at once. Just open the line edit without the best default; when the default is known, check the edited() return value and set the line edit's contents if the user has not started editing the line edit.

Calling setText() resets the edited flag to FALSE.

Set this property's value with setEdited() and get this property's value with edited().

bool frame

This property holds whether the line edit draws itself with a frame.

If enabled (the default) the line edit draws itself inside a two-pixel frame, otherwise the line edit draws itself without any frame.

Set this property's value with setFrame() and get this property's value with frame().

bool hasMarkedText

This property holds whether part of the text has been selected by the user (e.g., by clicking and dragging).

Get this property's value with hasMarkedText().

See also selectedText.

QString markedText

This property holds the text selected by the user (e.g., by clicking and dragging), or QString::null if no text is selected.

Get this property's value with markedText().

See also hasSelectedText.

int maxLength

This property holds the maximum permitted length of the text in the editor.

If the text is too long, it is chopped off at the limit. Any marked text will be unmarked. The cursor position is set to 0 and the first part of the string is shown.

Set this property's value with setMaxLength() and get this property's value with maxLength().

bool readOnly

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, but cannot edit it.

QLineEdit does not show a cursor in read-only mode.

Set this property's value with setReadOnly() and get this property's value with isReadOnly().

See also enabled.

QString text

This property holds the text in the line.

Setting this property clears the selection and moves the cursor to the end of the line.

The text is truncated to maxLength() length.

Set this property's value with setText() and get this property's value with text().


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