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authorVenugopal Shivashankar <venugopal.shivashankar@digia.com>2012-12-14 14:19:43 +0100
committerThe Qt Project <gerrit-noreply@qt-project.org>2012-12-18 07:20:56 +0100
commit85338a9c638f080e54ae9047dd5a86de3509199d (patch)
treea0d618ee104247028243ff4496fe7baa0d128692 /src
parent4dc45567a0b910a7678097dfc749337d85efb341 (diff)
Doc: Moved content from qtdoc
- The qdoc pages were related to qtcore and they were referring to snippets inside the qtcore module boundary. - Fixed the exampledirs for QtCore to include the examples that are referred by the \snippet instances in the moved qdoc pages work. Change-Id: Ibb6dbb131920ea8692a203f6145863e5012e4602 Reviewed-by: Jerome Pasion <jerome.pasion@digia.com> (cherry picked from commit 69e602941112da325b1154e0dc52714bc27a2cc8) Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Diffstat (limited to 'src')
-rw-r--r--src/corelib/doc/qtcore.qdocconf4
-rw-r--r--src/corelib/doc/src/custom-types.qdoc165
-rw-r--r--src/corelib/doc/src/objectmodel/object.qdoc3
-rw-r--r--src/corelib/doc/src/timers.qdoc123
4 files changed, 293 insertions, 2 deletions
diff --git a/src/corelib/doc/qtcore.qdocconf b/src/corelib/doc/qtcore.qdocconf
index e0c74c9ae5..7e6d06eaa6 100644
--- a/src/corelib/doc/qtcore.qdocconf
+++ b/src/corelib/doc/qtcore.qdocconf
@@ -35,6 +35,8 @@ sourcedirs += ..
exampledirs += \
../ \
snippets \
- ../../../examples/threads
+ ../../../examples/threads/ \
+ ../../../examples/tools/ \
+ ../../../examples/widgets/widgets/analogclock
imagedirs += images
diff --git a/src/corelib/doc/src/custom-types.qdoc b/src/corelib/doc/src/custom-types.qdoc
new file mode 100644
index 0000000000..95987ec014
--- /dev/null
+++ b/src/corelib/doc/src/custom-types.qdoc
@@ -0,0 +1,165 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:FDL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia. For licensing terms and
+** conditions see http://qt.digia.com/licensing. For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Free Documentation License Usage
+** 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. Please review the following information to ensure
+** the GNU Free Documentation License version 1.3 requirements
+** will be met: http://www.gnu.org/copyleft/fdl.html.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+ \page custom-types.html
+ \title Creating Custom Qt Types
+ \brief How to create and register new types with Qt.
+
+ \ingroup best-practices
+
+ \tableofcontents
+
+ \section1 Overview
+
+ When creating user interfaces with Qt, particularly those with specialized controls and
+ features, developers sometimes need to create new data types that can be used alongside
+ or in place of Qt's existing set of value types.
+
+ Standard types such as QSize, QColor and QString can all be stored in QVariant objects,
+ used as the types of properties in QObject-based classes, and emitted in signal-slot
+ communication.
+
+ In this document, we take a custom type and describe how to integrate it into Qt's object
+ model so that it can be stored in the same way as standard Qt types. We then show how to
+ register the custom type to allow it to be used in signals and slots connections.
+
+ \section1 Creating a Custom Type
+
+ Before we begin, we need to ensure that the custom type we are creating meets all the
+ requirements imposed by QMetaType. In other words, it must provide:
+
+ \list
+ \li a public default constructor,
+ \li a public copy constructor, and
+ \li a public destructor.
+ \endlist
+
+ The following \c Message class definition includes these members:
+
+ \snippet customtype/message.h custom type definition
+
+ The class also provides a constructor for normal use and two public member functions
+ that are used to obtain the private data.
+
+ \section1 Declaring the Type with QMetaType
+
+ The \c Message class only needs a suitable implementation in order to be usable.
+ However, Qt's type system will not be able to understand how to store, retrieve
+ and serialize instances of this class without some assistance. For example, we
+ will be unable to store \c Message values in QVariant.
+
+ The class in Qt responsible for custom types is QMetaType. To make the type known
+ to this class, we invoke the Q_DECLARE_METATYPE() macro on the class in the header
+ file where it is defined:
+
+ \snippet customtype/message.h custom type meta-type declaration
+
+ This now makes it possible for \c Message values to be stored in QVariant objects
+ and retrieved later. See the \l{Custom Type Example} for code that demonstrates
+ this.
+
+ The Q_DECLARE_METATYPE() macro also makes it possible for these values to be used as
+ arguments to signals, but \e{only in direct signal-slot connections}.
+ To make the custom type generally usable with the signals and slots mechanism, we
+ need to perform some extra work.
+
+ \section1 Creating and Destroying Custom Objects
+
+ Although the declaration in the previous section makes the type available for use
+ in direct signal-slot connections, it cannot be used for queued signal-slot
+ connections, such as those that are made between objects in different threads.
+ This is because the meta-object system does not know how to handle creation and
+ destruction of objects of the custom type at run-time.
+
+ To enable creation of objects at run-time, call the qRegisterMetaType() template
+ function to register it with the meta-object system. This also makes the type
+ available for queued signal-slot communication as long as you call it before you
+ make the first connection that uses the type.
+
+ The \l{Queued Custom Type Example} declares a \c Block class which is registered
+ in the \c{main.cpp} file:
+
+ \snippet queuedcustomtype/main.cpp main start
+ \dots
+ \snippet queuedcustomtype/main.cpp register meta-type for queued communications
+ \dots
+ \snippet queuedcustomtype/main.cpp main finish
+
+ This type is later used in a signal-slot connection in the \c{window.cpp} file:
+
+ \snippet queuedcustomtype/window.cpp Window constructor start
+ \dots
+ \snippet queuedcustomtype/window.cpp connecting signal with custom type
+ \dots
+ \snippet queuedcustomtype/window.cpp Window constructor finish
+
+ If a type is used in a queued connection without being registered, a warning will be
+ printed at the console; for example:
+
+ \code
+ QObject::connect: Cannot queue arguments of type 'Block'
+ (Make sure 'Block' is registered using qRegisterMetaType().)
+ \endcode
+
+ \section1 Making the Type Printable
+
+ It is often quite useful to make a custom type printable for debugging purposes,
+ as in the following code:
+
+ \snippet customtype/main.cpp printing a custom type
+
+ This is achieved by creating a streaming operator for the type, which is often
+ defined in the header file for that type:
+
+ \snippet customtype/message.h custom type streaming operator
+
+ The implementation for the \c Message type in the \l{Custom Type Example}
+ goes to some effort to make the printable representation as readable as
+ possible:
+
+ \snippet customtype/message.cpp custom type streaming operator
+
+ The output sent to the debug stream can, of course, be made as simple or as
+ complicated as you like. Note that the value returned by this function is
+ the QDebug object itself, though this is often obtained by calling the
+ maybeSpace() member function of QDebug that pads out the stream with space
+ characters to make it more readable.
+
+ \section1 Further Reading
+
+ The Q_DECLARE_METATYPE() macro and qRegisterMetaType() function documentation
+ contain more detailed information about their uses and limitations.
+
+ The \l{Custom Type Example}{Custom Type},
+ \l{Custom Type Sending Example}{Custom Type Sending}
+ and \l{Queued Custom Type Example}{Queued Custom Type} examples show how to
+ implement a custom type with the features outlined in this document.
+
+ The \l{Debugging Techniques} document provides an overview of the debugging
+ mechanisms discussed above.
+*/
diff --git a/src/corelib/doc/src/objectmodel/object.qdoc b/src/corelib/doc/src/objectmodel/object.qdoc
index 47f56372de..edf5673da0 100644
--- a/src/corelib/doc/src/objectmodel/object.qdoc
+++ b/src/corelib/doc/src/objectmodel/object.qdoc
@@ -47,7 +47,7 @@
properties}
\li powerful \l{The Event System}{events and event filters}
\li contextual \l{i18n}{string translation for internationalization}
- \li sophisticated interval driven \l timers that make it possible
+ \li sophisticated interval driven \l {Timers}{timers} that make it possible
to elegantly integrate many tasks in an event-driven GUI
\li hierarchical and queryable \l{Object Trees & Ownership}{object
trees} that organize object ownership in a natural way
@@ -56,6 +56,7 @@
pointers which become dangling pointers when their objects are destroyed
\li a \l{metaobjects.html#qobjectcast}{dynamic cast} that works across
library boundaries.
+ \li support for \l{Creating Custom Qt Types}{custom type} creation.
\endlist
Many of these Qt features are implemented with standard C++
diff --git a/src/corelib/doc/src/timers.qdoc b/src/corelib/doc/src/timers.qdoc
new file mode 100644
index 0000000000..eddb600559
--- /dev/null
+++ b/src/corelib/doc/src/timers.qdoc
@@ -0,0 +1,123 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:FDL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia. For licensing terms and
+** conditions see http://qt.digia.com/licensing. For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Free Documentation License Usage
+** 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. Please review the following information to ensure
+** the GNU Free Documentation License version 1.3 requirements
+** will be met: http://www.gnu.org/copyleft/fdl.html.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+ \page timers.html
+ \title Timers
+ \brief How to use Qt timers in your application.
+
+ \ingroup best-practices
+
+ QObject, the base class of all Qt objects, provides the basic
+ timer support in Qt. With QObject::startTimer(), you start a
+ timer with an interval in milliseconds as argument. The function
+ returns a unique integer timer ID. The timer will now fire at
+ regular intervals until you explicitly call QObject::killTimer()
+ with the timer ID.
+
+ For this mechanism to work, the application must run in an event
+ loop. You start an event loop with QApplication::exec(). When a
+ timer fires, the application sends a QTimerEvent, and the flow of
+ control leaves the event loop until the timer event is processed.
+ This implies that a timer cannot fire while your application is
+ busy doing something else. In other words: the accuracy of timers
+ depends on the granularity of your application.
+
+ In multithreaded applications, you can use the timer mechanism in
+ any thread that has an event loop. To start an event loop from a
+ non-GUI thread, use QThread::exec(). Qt uses the object's
+ \l{QObject::thread()}{thread affinity} to determine which thread
+ will deliver the QTimerEvent. Because of this, you must start and
+ stop all timers in the object's thread; it is not possible to
+ start timers for objects in another thread.
+
+ The upper limit for the interval value is determined by the number
+ of milliseconds that can be specified in a signed integer
+ (in practice, this is a period of just over 24 days). The accuracy
+ depends on the underlying operating system. Windows 2000 has 15
+ millisecond accuracy; other systems that we have tested can handle
+ 1 millisecond intervals.
+
+ The main API for the timer functionality is QTimer. That class
+ provides regular timers that emit a signal when the timer fires, and
+ inherits QObject so that it fits well into the ownership structure
+ of most GUI programs. The normal way of using it is like this:
+
+ \snippet timers/timers.cpp 0
+ \snippet timers/timers.cpp 1
+ \snippet timers/timers.cpp 2
+
+ The QTimer object is made into a child of this widget so that,
+ when this widget is deleted, the timer is deleted too.
+ Next, its \l{QTimer::}{timeout()} signal is connected to the slot
+ that will do the work, it is started with a value of 1000
+ milliseconds, indicating that it will time out every second.
+
+ QTimer also provides a static function for single-shot timers.
+ For example:
+
+ \snippet timers/timers.cpp 3
+
+ 200 milliseconds (0.2 seconds) after this line of code is
+ executed, the \c updateCaption() slot will be called.
+
+ For QTimer to work, you must have an event loop in your
+ application; that is, you must call QCoreApplication::exec()
+ somewhere. Timer events will be delivered only while the event
+ loop is running.
+
+ In multithreaded applications, you can use QTimer in any thread
+ that has an event loop. To start an event loop from a non-GUI
+ thread, use QThread::exec(). Qt uses the timer's
+ \l{QObject::thread()}{thread affinity} to determine which thread
+ will emit the \l{QTimer::}{timeout()} signal. Because of this, you
+ must start and stop the timer in its thread; it is not possible to
+ start a timer from another thread.
+
+ The \l{widgets/analogclock}{Analog Clock} example shows how to use
+ QTimer to redraw a widget at regular intervals. From \c{AnalogClock}'s
+ implementation:
+
+ \snippet analogclock.cpp 0
+ \snippet analogclock.cpp 2
+ \snippet analogclock.cpp 3
+ \snippet analogclock.cpp 4
+ \snippet analogclock.cpp 5
+ \snippet analogclock.cpp 6
+ \dots
+ \snippet analogclock.cpp 7
+
+ Every second, QTimer will call the QWidget::update() slot to
+ refresh the clock's display.
+
+ If you already have a QObject subclass and want an easy
+ optimization, you can use QBasicTimer instead of QTimer. With
+ QBasicTimer, you must reimplement
+ \l{QObject::timerEvent()}{timerEvent()} in your QObject subclass
+ and handle the timeout there. The \l{widgets/wiggly}{Wiggly}
+ example shows how to use QBasicTimer.
+*/