QLabel Class ReferenceThe QLabel widget provides a text or image display. Далее... #include <QLabel>Inherits: QFrame. От него наследуются: Свойства
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Подробное описаниеThe QLabel widget provides a text or image display. QLabel is used for displaying text or an image. No user interaction functionality is provided. The visual appearance of the label can be configured in various ways, and it can be used for specifying a focus mnemonic key for another widget. A QLabel can contain any of the following content types:
Warning: When passing a QString to the constructor or calling setText(), make sure to sanitize your input, as QLabel tries to guess whether it displays the text as plain text or as rich text. You may want to call setTextFormat() explicitly, e.g. in case you expect the text to be in plain format but cannot control the text source (for instance when displaying data loaded from the Web). When the content is changed using any of these functions, any previous content is cleared. By default, labels display left-aligned, vertically-centered text and images, where any tabs in the text to be displayed are automatically expanded. However, the look of a QLabel can be adjusted and fine-tuned in several ways. The positioning of the content within the QLabel widget area can be tuned with setAlignment() and setIndent(). Text content can also wrap lines along word boundaries with setWordWrap(). For example, this code sets up a sunken panel with a two-line text in the bottom right corner (both lines being flush with the right side of the label): QLabel *label = new QLabel(this); label->setFrameStyle(QFrame::Panel | QFrame::Sunken); label->setText("first line\nsecond line"); label->setAlignment(Qt::AlignBottom | Qt::AlignRight); The properties and functions QLabel inherits from QFrame can also be used to specify the widget frame to be used for any given label. A QLabel is often used as a label for an interactive widget. For this use QLabel provides a useful mechanism for adding an mnemonic (see QKeySequence) that will set the keyboard focus to the other widget (called the QLabel's "buddy"). Например: QLineEdit* phoneEdit = new QLineEdit(this); QLabel* phoneLabel = new QLabel("&Phone:", this); phoneLabel->setBuddy(phoneEdit); In this example, keyboard focus is transferred to the label's buddy (the QLineEdit) when the user presses Alt+P. If the buddy was a button (inheriting from QAbstractButton), triggering the mnemonic would emulate a button click.
See also QLineEdit, QTextEdit, QPixmap, QMovie, and GUI Design Handbook: Label. Описание свойствalignment : Qt::AlignmentThis property holds the alignment of the label's contents. By default, the contents of the label are left-aligned and vertically-centered. Функции доступа:
Смотрите также text. hasSelectedText : const boolThis property holds whether there is any text selected. hasSelectedText() returns true if some or all of the text has been selected by the user; otherwise returns false. По умолчанию это свойство равно false. Note: The textInteractionFlags set on the label need to include either TextSelectableByMouse or TextSelectableByKeyboard. Это свойство было введено в Qt 4.7. Функции доступа:
See also selectedText(). indent : intThis property holds the label's text indent in pixels. If a label displays text, the indent applies to the left edge if alignment() is Qt::AlignLeft, to the right edge if alignment() is Qt::AlignRight, to the top edge if alignment() is Qt::AlignTop, and to to the bottom edge if alignment() is Qt::AlignBottom. If indent is negative, or if no indent has been set, the label computes the effective indent as follows: If frameWidth() is 0, the effective indent becomes 0. If frameWidth() is greater than 0, the effective indent becomes half the width of the "x" character of the widget's current font(). By default, the indent is -1, meaning that an effective indent is calculating in the manner described above. Функции доступа:
See also alignment, margin, frameWidth(), and font(). margin : intThis property holds the width of the margin. The margin is the distance between the innermost pixel of the frame and the outermost pixel of contents. The default margin is 0. Функции доступа:
See also indent. openExternalLinks : boolSpecifies whether QLabel should automatically open links using QDesktopServices::openUrl() instead of emitting the linkActivated() signal. Note: The textInteractionFlags set on the label need to include either LinksAccessibleByMouse or LinksAccessibleByKeyboard. Значение по умолчанию равно false. Это свойство было введено в Qt 4.2. Функции доступа:
Смотрите также textInteractionFlags(). pixmap : QPixmapThis property holds the label's pixmap. If no pixmap has been set this will return 0. Setting the pixmap clears any previous content. The buddy shortcut, if any, is disabled. Функции доступа:
scaledContents : boolThis property holds whether the label will scale its contents to fill all available space. When enabled and the label shows a pixmap, it will scale the pixmap to fill the available space. This property's default is false. Функции доступа:
selectedText : const QStringThis property holds the selected text. If there is no selected text this property's value is an empty string. По умолчанию это свойство содержит пустую строку. Note: The textInteractionFlags set on the label need to include either TextSelectableByMouse or TextSelectableByKeyboard. Это свойство было введено в Qt 4.7. Функции доступа:
See also hasSelectedText(). text : QStringThis property holds the label's text. If no text has been set this will return an empty string. Setting the text clears any previous content. The text will be interpreted either as plain text or as rich text, depending on the text format setting; see setTextFormat(). The default setting is Qt::AutoText; i.e. QLabel will try to auto-detect the format of the text set. If a buddy has been set, the buddy mnemonic key is updated from the new text. Note that QLabel is well-suited to display small rich text documents, such as small documents that get their document specific settings (font, text color, link color) from the label's palette and font properties. For large documents, use QTextEdit in read-only mode instead. QTextEdit can also provide a scroll bar when necessary. Note: This function enables mouse tracking if text contains rich text. Функции доступа:
See also setTextFormat(), setBuddy(), and alignment. textFormat : Qt::TextFormatThis property holds the label's text format. See the Qt::TextFormat enum for an explanation of the possible options. The default format is Qt::AutoText. Функции доступа:
Смотрите также text(). textInteractionFlags : Qt::TextInteractionFlagsSpecifies how the label should interact with user input if it displays text. If the flags contain Qt::LinksAccessibleByKeyboard the focus policy is also automatically set to Qt::StrongFocus. If Qt::TextSelectableByKeyboard is set then the focus policy is set to Qt::ClickFocus. The default value is Qt::LinksAccessibleByMouse. Это свойство было введено в Qt 4.2. Функции доступа:
wordWrap : boolThis property holds the label's word-wrapping policy. If this property is true then label text is wrapped where necessary at word-breaks; otherwise it is not wrapped at all. By default, word wrap is disabled. Функции доступа:
Смотрите также text. Описание функций-членовQLabel::QLabel ( QWidget * parent = 0, Qt::WindowFlags f = 0 )Создаёт пустую метку. The parent and widget flag f, arguments are passed to the QFrame constructor. Смотрите также setAlignment(), setFrameStyle() и setIndent(). QLabel::QLabel ( const QString & text, QWidget * parent = 0, Qt::WindowFlags f = 0 )Создаёт метку, которая отображает текст text. The parent and widget flag f, arguments are passed to the QFrame constructor. Смотрите также setText(), setAlignment(), setFrameStyle() и setIndent(). QLabel::~QLabel ()Destroys the label. QWidget * QLabel::buddy () constReturns this label's buddy, or 0 if no buddy is currently set. See also setBuddy(). void QLabel::changeEvent ( QEvent * ev ) [virtual protected]Переопределено от QWidget::changeEvent(). void QLabel::clear () [slot]Clears any label contents. void QLabel::contextMenuEvent ( QContextMenuEvent * ev ) [virtual protected]Переопределено из QWidget::contextMenuEvent(). bool QLabel::event ( QEvent * e ) [virtual protected]Переопределено от QObject::event(). void QLabel::focusInEvent ( QFocusEvent * ev ) [virtual protected]Переопределено из QWidget::focusInEvent(). bool QLabel::focusNextPrevChild ( bool next ) [virtual protected]Переопределено из QWidget::focusNextPrevChild(). void QLabel::focusOutEvent ( QFocusEvent * ev ) [virtual protected]Переопределено из QWidget::focusOutEvent(). int QLabel::heightForWidth ( int w ) const [virtual]Переопределено от QWidget::heightForWidth(). void QLabel::keyPressEvent ( QKeyEvent * ev ) [virtual protected]Переопределено от QWidget::keyPressEvent(). void QLabel::linkActivated ( const QString & link ) [signal]This signal is emitted when the user clicks a link. The URL referred to by the anchor is passed in link. Эта функция была введена в Qt 4.2. See also linkHovered(). void QLabel::linkHovered ( const QString & link ) [signal]This signal is emitted when the user hovers over a link. The URL referred to by the anchor is passed in link. Эта функция была введена в Qt 4.2. See also linkActivated(). QSize QLabel::minimumSizeHint () const [virtual]Переопределено от QWidget::minimumSizeHint(). void QLabel::mouseMoveEvent ( QMouseEvent * ev ) [virtual protected]Переопределено из QWidget::mouseMoveEvent(). void QLabel::mousePressEvent ( QMouseEvent * ev ) [virtual protected]Переопределено из QWidget::mousePressEvent(). void QLabel::mouseReleaseEvent ( QMouseEvent * ev ) [virtual protected]Переопределено из QWidget::mouseReleaseEvent(). QMovie * QLabel::movie () constReturns a pointer to the label's movie, or 0 if no movie has been set. See also setMovie(). void QLabel::paintEvent ( QPaintEvent * ) [virtual protected]Переопределено от QWidget::paintEvent(). const QPicture * QLabel::picture () constReturns the label's picture or 0 if the label doesn't have a picture. See also setPicture(). int QLabel::selectionStart () constselectionStart() returns the index of the first selected character in the label or -1 if no text is selected. Note: The textInteractionFlags set on the label need to include either TextSelectableByMouse or TextSelectableByKeyboard. Эта функция была введена в Qt 4.7. See also selectedText(). void QLabel::setBuddy ( QWidget * buddy )Sets this label's buddy to buddy. When the user presses the shortcut key indicated by this label, the keyboard focus is transferred to the label's buddy widget. The buddy mechanism is only available for QLabels that contain text in which one character is prefixed with an ampersand, '&'. This character is set as the shortcut key. See the QKeySequence::mnemonic() documentation for details (to display an actual ampersand, use '&&'). In a dialog, you might create two data entry widgets and a label for each, and set up the geometry layout so each label is just to the left of its data entry widget (its "buddy"), for example: QLineEdit *nameEd = new QLineEdit(this); QLabel *nameLb = new QLabel("&Name:", this); nameLb->setBuddy(nameEd); QLineEdit *phoneEd = new QLineEdit(this); QLabel *phoneLb = new QLabel("&Phone:", this); phoneLb->setBuddy(phoneEd); // (layout setup not shown) With the code above, the focus jumps to the Name field when the user presses Alt+N, and to the Phone field when the user presses Alt+P. To unset a previously set buddy, call this function with buddy set to 0. See also buddy(), setText(), QShortcut, and setAlignment(). void QLabel::setMovie ( QMovie * movie ) [slot]Sets the label contents to movie. Any previous content is cleared. The label does NOT take ownership of the movie. The buddy shortcut, if any, is disabled. See also movie() and setBuddy(). void QLabel::setNum ( int num ) [slot]Sets the label contents to plain text containing the textual representation of integer num. Any previous content is cleared. Does nothing if the integer's string representation is the same as the current contents of the label. The buddy shortcut, if any, is disabled. See also setText(), QString::setNum(), and setBuddy(). void QLabel::setNum ( double num ) [slot]Это перегруженная функция. Sets the label contents to plain text containing the textual representation of double num. Any previous content is cleared. Does nothing if the double's string representation is the same as the current contents of the label. The buddy shortcut, if any, is disabled. See also setText(), QString::setNum(), and setBuddy(). void QLabel::setPicture ( const QPicture & picture ) [slot]Sets the label contents to picture. Any previous content is cleared. The buddy shortcut, if any, is disabled. See also picture() and setBuddy(). void QLabel::setSelection ( int start, int length )Selects text from position start and for length characters. Note: The textInteractionFlags set on the label need to include either TextSelectableByMouse or TextSelectableByKeyboard. Эта функция была введена в Qt 4.7. See also selectedText(). QSize QLabel::sizeHint () const [virtual]Переопределено от QWidget::sizeHint(). |
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