/**************************************************************************** ** ** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies). ** Contact: http://www.qt-project.org/ ** ** This file is part of the documentation of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:FDL$ ** GNU Free Documentation License ** Alternatively, this file may be used under the terms of the GNU Free ** Documentation License version 1.3 as published by the Free Software ** Foundation and appearing in the file included in the packaging of ** this file. ** ** Other Usage ** Alternatively, this file may be used in accordance with the terms ** and conditions contained in a signed written agreement between you ** and Nokia. ** ** ** ** ** ** $QT_END_LICENSE$ ** ****************************************************************************/ /*! \example widgets/digitalclock \title Digital Clock Example The Digital Clock example shows how to use QLCDNumber to display a number with LCD-like digits. \image digitalclock-example.png Screenshot of the Digital Clock example This example also demonstrates how QTimer can be used to update a widget at regular intervals. \section1 DigitalClock Class Definition The \c DigitalClock class provides a clock widget showing the time with hours and minutes separated by a blinking colon. We subclass QLCDNumber and implement a private slot called \c showTime() to update the clock display: \snippet examples/widgets/digitalclock/digitalclock.h 0 \section1 DigitalClock Class Implementation \snippet examples/widgets/digitalclock/digitalclock.cpp 0 In the constructor, we first change the look of the LCD numbers. The QLCDNumber::Filled style produces raised segments filled with the foreground color (typically black). We also set up a one-second timer to keep track of the current time, and we connect its \l{QTimer::timeout()}{timeout()} signal to the private \c showTime() slot so that the display is updated every second. Then, we call the \c showTime() slot; without this call, there would be a one-second delay at startup before the time is shown. \snippet examples/widgets/digitalclock/digitalclock.cpp 1 \snippet examples/widgets/digitalclock/digitalclock.cpp 2 The \c showTime() slot is called whenever the clock display needs to be updated. The current time is converted into a string with the format "hh:mm". When QTime::second() is a even number, the colon in the string is replaced with a space. This makes the colon appear and vanish every other second. Finally, we call QLCDNumber::display() to update the widget. */