QLineEdit Class

Member Function Documentation

QLineEdit::QLineEdit(const QString &contents, QWidget *parent = nullptr)

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 QWidget constructor.

See also text() and setMaxLength().

QLineEdit::QLineEdit(QWidget *parent = nullptr)

Constructs a line edit with no text.

The maximum text length is set to 32767 characters.

The parent argument is sent to the QWidget constructor.

See also setText() and setMaxLength().

[slot] void QLineEdit::clear()

Clears the contents of the line edit.

See also setText() and insert().

[slot] void QLineEdit::copy() const

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

See also cut() and paste().

[signal] void QLineEdit::cursorPositionChanged(int oldPos, int newPos)

This signal is emitted whenever the cursor moves. The previous position is given by oldPos, and the new position by newPos.

See also setCursorPosition() and cursorPosition().

[slot] void QLineEdit::cut()

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

If the current validator disallows deleting the selected text, cut() will copy without deleting.

See also copy(), paste(), and setValidator().

[signal] void QLineEdit::editingFinished()

This signal is emitted when the Return or Enter key is pressed, or if the line edit loses focus and its contents have changed since the last time this signal was emitted.

Note that if there is a validator() or inputMask() set on the line edit and enter/return is pressed, the editingFinished() signal will only be emitted if the input follows the inputMask() and the validator() returns QValidator::Acceptable.

[signal, since 5.12] void QLineEdit::inputRejected()

This signal is emitted when the user presses a key that is not considered to be acceptable input. For example, if a key press results in a validator's validate() call to return Invalid. Another case is when trying to enter in more characters beyond the maximum length of the line edit.

Note: This signal will still be emitted in a case where part of the text is accepted but not all of it is. For example, if there is a maximum length set and the clipboard text is longer than the maximum length when it is pasted.

This function was introduced in Qt 5.12.

[slot] void QLineEdit::paste()

Inserts the clipboard's text at the cursor position, deleting any selected text, providing the line edit is not read-only.

If the end result would be invalid to the current validator, nothing happens.

See also copy() and cut().

[slot] void QLineEdit::redo()

Redoes the last operation if redo is available.

[signal] void QLineEdit::returnPressed()

This signal is emitted when the Return or Enter key is pressed. Note that if there is a validator() or inputMask() set on the line edit, the returnPressed() signal will only be emitted if the input follows the inputMask() and the validator() returns QValidator::Acceptable.

[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 setSelection() and deselect().

[signal] void QLineEdit::selectionChanged()

This signal is emitted whenever the selection changes.

See also hasSelectedText() and selectedText().

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

This signal is emitted whenever the text changes. The text argument is the new text.

Unlike textEdited(), this signal is also emitted when the text is changed programmatically, for example, by calling setText().

Note: Notifier signal for property text.

[signal] void QLineEdit::textEdited(const QString &text)

This signal is emitted whenever the text is edited. The text argument is the new text.

Unlike textChanged(), this signal is not emitted when the text is changed programmatically, for example, by calling setText().

[slot] void QLineEdit::undo()

Undoes the last operation if undo is available. Deselects any current selection, and updates the selection start to the current cursor position.

[virtual] QLineEdit::~QLineEdit()

Destroys the line edit.

[since 5.2] void QLineEdit::addAction(QAction *action, QLineEdit::ActionPosition position)

Adds the action to the list of actions at the position.

This function was introduced in Qt 5.2.

[since 5.2] QAction *QLineEdit::addAction(const QIcon &icon, QLineEdit::ActionPosition position)

This is an overloaded function.

Creates a new action with the given icon at the position.

This function was introduced in Qt 5.2.

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 del().

[override virtual protected] void QLineEdit::changeEvent(QEvent *ev)

Reimplements: QWidget::changeEvent(QEvent *event).

QCompleter *QLineEdit::completer() const

Returns the current QCompleter that provides completions.

See also setCompleter().

[override virtual protected] void QLineEdit::contextMenuEvent(QContextMenuEvent *event)

Reimplements: QWidget::contextMenuEvent(QContextMenuEvent *event).

Shows the standard context menu created with createStandardContextMenu().

If you do not want the line edit to have a context menu, you can set its contextMenuPolicy to Qt::NoContextMenu. If you want to customize the context menu, reimplement this function. If you want to extend the standard context menu, reimplement this function, call createStandardContextMenu() and extend the menu returned.

 void LineEdit::contextMenuEvent(QContextMenuEvent *event)
 {
     QMenu *menu = createStandardContextMenu();
     menu->addAction(tr("My Menu Item"));
     //...
     menu->exec(event->globalPos());
     delete menu;
 }

The event parameter is used to obtain the position where the mouse cursor was when the event was generated.

See also setContextMenuPolicy().

QMenu *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 contextMenuEvent() 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 added to the selection; if mark is false the selection is cleared.

See also cursorForward().

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

Moves the cursor forward steps characters. If mark is true each character moved over is added to the selection; if mark is false the selection is cleared.

See also cursorBackward().

int QLineEdit::cursorPositionAt(const QPoint &pos)

Returns the cursor position under the point pos.

[protected] QRect QLineEdit::cursorRect() const

Returns a rectangle that includes the lineedit cursor.

void QLineEdit::cursorWordBackward(bool mark)

Moves the cursor one word backward. If mark is true, the word is also selected.

See also cursorWordForward().

void QLineEdit::cursorWordForward(bool mark)

Moves the cursor one word forward. If mark is true, the word is also selected.

See also cursorWordBackward().

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 backspace().

void QLineEdit::deselect()

Deselects any selected text.

See also setSelection() and selectAll().

[override virtual protected] void QLineEdit::dragEnterEvent(QDragEnterEvent *e)

Reimplements: QWidget::dragEnterEvent(QDragEnterEvent *event).

[override virtual protected] void QLineEdit::dragLeaveEvent(QDragLeaveEvent *e)

Reimplements: QWidget::dragLeaveEvent(QDragLeaveEvent *event).

[override virtual protected] void QLineEdit::dragMoveEvent(QDragMoveEvent *e)

Reimplements: QWidget::dragMoveEvent(QDragMoveEvent *event).

[override virtual protected] void QLineEdit::dropEvent(QDropEvent *e)

Reimplements: QWidget::dropEvent(QDropEvent *event).

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 towards the last position; otherwise, any selected text is unselected if the cursor is moved.

See also home().

[override virtual] bool QLineEdit::event(QEvent *e)

Reimplements: QWidget::event(QEvent *event).

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

Reimplements: QWidget::focusInEvent(QFocusEvent *event).

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

Reimplements: QWidget::focusOutEvent(QFocusEvent *event).

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 towards the first position; otherwise, any selected text is unselected if the cursor is moved.

See also end().

[virtual protected] void QLineEdit::initStyleOption(QStyleOptionFrame *option) const

Initialize option with the values from this QLineEdit. This method is useful for subclasses when they need a QStyleOptionFrame, but don't want to fill in all the information themselves.

See also QStyleOption::initFrom().

[override virtual protected] void QLineEdit::inputMethodEvent(QInputMethodEvent *e)

Reimplements: QWidget::inputMethodEvent(QInputMethodEvent *event).

[override virtual] QVariant QLineEdit::inputMethodQuery(Qt::InputMethodQuery property) const

Reimplements: QWidget::inputMethodQuery(Qt::InputMethodQuery query) const.

void QLineEdit::insert(const QString &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 setText() and clear().

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

Reimplements: QWidget::keyPressEvent(QKeyEvent *event).

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 made valid by the validator), the signal returnPressed() is emitted.

The default key bindings are listed in the class's detailed description.

[override virtual protected] void QLineEdit::keyReleaseEvent(QKeyEvent *)

Reimplements: QWidget::keyReleaseEvent(QKeyEvent *event).

[override virtual] QSize QLineEdit::minimumSizeHint() const

Reimplements an access function for property: QWidget::minimumSizeHint.

Returns a minimum size for the line edit.

The width returned is usually enough for at least one character.

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

Reimplements: QWidget::mouseDoubleClickEvent(QMouseEvent *event).

[override virtual protected] void QLineEdit::mouseMoveEvent(QMouseEvent *e)

Reimplements: QWidget::mouseMoveEvent(QMouseEvent *event).

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

Reimplements: QWidget::mousePressEvent(QMouseEvent *event).

[override virtual protected] void QLineEdit::mouseReleaseEvent(QMouseEvent *e)

Reimplements: QWidget::mouseReleaseEvent(QMouseEvent *event).

[override virtual protected] void QLineEdit::paintEvent(QPaintEvent *)

Reimplements: QWidget::paintEvent(QPaintEvent *event).

[since 5.10] int QLineEdit::selectionEnd() const

Returns the index of the character directly after the selection in the line edit or -1 if no text is selected.

This function was introduced in Qt 5.10.

See also selectedText(), selectionStart(), and selectionLength().

[since 5.10] int QLineEdit::selectionLength() const

Returns the length of the selection.

This function was introduced in Qt 5.10.

See also selectedText(), selectionStart(), and selectionEnd().

int QLineEdit::selectionStart() const

Returns the index of the first selected character in the line edit or -1 if no text is selected.

See also selectedText(), selectionEnd(), and selectionLength().

void QLineEdit::setCompleter(QCompleter *c)

Sets this line edit to provide auto completions from the completer, c. The completion mode is set using QCompleter::setCompletionMode().

To use a QCompleter with a QValidator or QLineEdit::inputMask, you need to ensure that the model provided to QCompleter contains valid entries. You can use the QSortFilterProxyModel to ensure that the QCompleter's model contains only valid entries.

If c == 0, setCompleter() removes the current completer, effectively disabling auto completion.

See also completer() and QCompleter.

void QLineEdit::setSelection(int start, int length)

Selects text from position start and for length characters. Negative lengths are allowed.

See also deselect(), selectAll(), and selectedText().

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 textMargins().

See also textMargins().

void QLineEdit::setTextMargins(const QMargins &margins)

Sets the margins around the text inside the frame.

See also textMargins().

void QLineEdit::setValidator(const QValidator *v)

Sets the validator for values of line edit to v.

The line edit's returnPressed() and editingFinished() signals will only be emitted if v validates the line edit's content as Acceptable. The user may change the content to any Intermediate value during editing, but will be prevented from editing the text to a value that v validates as Invalid.

This allows you to constrain the text that shall finally be entered when editing is done, while leaving users with enough freedom to edit the text from one valid state to another.

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(), hasAcceptableInput(), QIntValidator, QDoubleValidator, and QRegularExpressionValidator.

[override virtual] QSize QLineEdit::sizeHint() const

Reimplements an access function for property: QWidget::sizeHint.

Returns a recommended size for the widget.

The width returned, in pixels, is usually enough for about 15 to 20 characters.

QMargins QLineEdit::textMargins() const

Returns the widget's text margins.

See also setTextMargins().

[override virtual] void QLineEdit::timerEvent(QTimerEvent *e)

Reimplements: QObject::timerEvent(QTimerEvent *event).

const QValidator *QLineEdit::validator() const

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

See also setValidator().