doc/src/examples/digitalclock.qdoc
author Eckhart Koeppen <eckhart.koppen@nokia.com>
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/****************************************************************************
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**
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** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
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** All rights reserved.
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** Contact: Nokia Corporation (qt-info@nokia.com)
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**
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** This file is part of the documentation of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:LGPL$
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** No Commercial Usage
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** This file contains pre-release code and may not be distributed.
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** You may use this file in accordance with the terms and conditions
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** contained in the Technology Preview License Agreement accompanying
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** this package.
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**
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** GNU Lesser General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** General Public License version 2.1 as published by the Free Software
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** Foundation and appearing in the file LICENSE.LGPL included in the
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** packaging of this file.  Please review the following information to
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** ensure the GNU Lesser General Public License version 2.1 requirements
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** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
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**
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** In addition, as a special exception, Nokia gives you certain additional
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** rights.  These rights are described in the Nokia Qt LGPL Exception
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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**
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** If you have questions regarding the use of this file, please contact
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** Nokia at qt-info@nokia.com.
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**
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**
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**
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**
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**
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**
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**
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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/*!
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    \example widgets/digitalclock
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    \title Digital Clock Example
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    The Digital Clock example shows how to use QLCDNumber to display a 
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    number with LCD-like digits.
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    \image digitalclock-example.png Screenshot of the Digital Clock example
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    This example also demonstrates how QTimer can be used to update a widget
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    at regular intervals.
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    \section1 DigitalClock Class Definition
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    The \c DigitalClock class provides a clock widget showing the time with
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    hours and minutes separated by a blinking colon. We subclass QLCDNumber
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    and implement a private slot called \c showTime() to update the clock
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    display:
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    \snippet examples/widgets/digitalclock/digitalclock.h 0
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    \section1 DigitalClock Class Implementation
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    \snippet examples/widgets/digitalclock/digitalclock.cpp 0
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    In the constructor, we first change the look of the LCD numbers. The
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    QLCDNumber::Filled style produces raised segments filled with the
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    foreground color (typically black). We also set up a one-second timer
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    to keep track of the current time, and we connect
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    its \l{QTimer::timeout()}{timeout()} signal to the private \c showTime() slot
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    so that the display is updated every second. Then, we
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    call the \c showTime() slot; without this call, there would be a one-second
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    delay at startup before the time is shown.
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    \snippet examples/widgets/digitalclock/digitalclock.cpp 1
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    \snippet examples/widgets/digitalclock/digitalclock.cpp 2
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    The \c showTime() slot is called whenever the clock display needs
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    to be updated.
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    The current time is converted into a string with the format "hh:mm".
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    When QTime::second() is a even number, the colon in the string is
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    replaced with a space. This makes the colon appear and vanish every
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    other second.
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    Finally, we call QLCDNumber::display() to update the widget.
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*/