| 1 | /****************************************************************************
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| 2 | **
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| 3 | ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
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| 4 | ** All rights reserved.
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| 5 | ** Contact: Nokia Corporation (qt-info@nokia.com)
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| 6 | **
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| 7 | ** This file is part of the documentation of the Qt Toolkit.
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| 8 | **
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| 9 | ** $QT_BEGIN_LICENSE:FDL$
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| 10 | ** Commercial Usage
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| 11 | ** Licensees holding valid Qt Commercial licenses may use this file in
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| 12 | ** accordance with the Qt Commercial License Agreement provided with the
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| 13 | ** Software or, alternatively, in accordance with the terms contained in a
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| 14 | ** written agreement between you and Nokia.
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| 15 | **
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| 16 | ** GNU Free Documentation License
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| 17 | ** Alternatively, this file may be used under the terms of the GNU Free
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| 18 | ** Documentation License version 1.3 as published by the Free Software
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| 19 | ** Foundation and appearing in the file included in the packaging of this
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| 20 | ** file.
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| 21 | **
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| 22 | ** If you have questions regarding the use of this file, please contact
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| 23 | ** Nokia at qt-info@nokia.com.
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| 24 | ** $QT_END_LICENSE$
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| 25 | **
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| 26 | ****************************************************************************/
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| 27 |
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| 28 | /*!
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| 29 | \example widgets/digitalclock
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| 30 | \title Digital Clock Example
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| 31 |
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| 32 | The Digital Clock example shows how to use QLCDNumber to display a
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| 33 | number with LCD-like digits.
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| 34 |
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| 35 | \image digitalclock-example.png Screenshot of the Digital Clock example
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| 36 |
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| 37 | This example also demonstrates how QTimer can be used to update a widget
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| 38 | at regular intervals.
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| 39 |
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| 40 | \section1 DigitalClock Class Definition
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| 41 |
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| 42 | The \c DigitalClock class provides a clock widget showing the time with
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| 43 | hours and minutes separated by a blinking colon. We subclass QLCDNumber
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| 44 | and implement a private slot called \c showTime() to update the clock
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| 45 | display:
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| 46 |
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| 47 | \snippet examples/widgets/digitalclock/digitalclock.h 0
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| 48 |
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| 49 | \section1 DigitalClock Class Implementation
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| 50 |
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| 51 | \snippet examples/widgets/digitalclock/digitalclock.cpp 0
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| 52 |
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| 53 | In the constructor, we first change the look of the LCD numbers. The
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| 54 | QLCDNumber::Filled style produces raised segments filled with the
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| 55 | foreground color (typically black). We also set up a one-second timer
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| 56 | to keep track of the current time, and we connect
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| 57 | its \l{QTimer::timeout()}{timeout()} signal to the private \c showTime() slot
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| 58 | so that the display is updated every second. Then, we
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| 59 | call the \c showTime() slot; without this call, there would be a one-second
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| 60 | delay at startup before the time is shown.
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| 61 |
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| 62 | \snippet examples/widgets/digitalclock/digitalclock.cpp 1
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| 63 | \snippet examples/widgets/digitalclock/digitalclock.cpp 2
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| 64 |
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| 65 | The \c showTime() slot is called whenever the clock display needs
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| 66 | to be updated.
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| 67 |
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| 68 | The current time is converted into a string with the format "hh:mm".
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| 69 | When QTime::second() is a even number, the colon in the string is
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| 70 | replaced with a space. This makes the colon appear and vanish every
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| 71 | other second.
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| 72 |
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| 73 | Finally, we call QLCDNumber::display() to update the widget.
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| 74 | */
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