diff options
Diffstat (limited to 'doc/src')
26 files changed, 1334 insertions, 56 deletions
diff --git a/doc/src/animation.qdoc b/doc/src/animation.qdoc index f8b6d4c..7a4e778 100644 --- a/doc/src/animation.qdoc +++ b/doc/src/animation.qdoc @@ -40,7 +40,7 @@ ****************************************************************************/ /*! - \page animation.html + \page animation-overview.html \title The Animation Framework \ingroup architecture \ingroup group_animation @@ -64,7 +64,10 @@ We will in this section take a high-level look at the animation framework's architecture and how it is used to animate Qt - properties. + properties. The following diagram shows the most important classes + in the animation framework. + + \image animations-architecture.png The animation framework foundation consists of the base class QAbstractAnimation, and its two subclasses QVariantAnimation and @@ -132,7 +135,7 @@ \endcode This code will move \c button from the top left corner of the - screen to the position (250, 250). + screen to the position (250, 250) in 10 seconds (10000 milliseconds). The example above will do a linear interpolation between the start and end value. It is also possible to set values @@ -162,7 +165,7 @@ that is not declared as a Qt property. The only requirement is that this value has a setter. You can then subclass the class containing the value and declare a property that uses this setter. - Note that all Qt properties requires a getter, so you will need to + Note that each Qt property requires a getter, so you will need to provide a getter yourself if this is not defined. \code @@ -184,9 +187,9 @@ \section1 Animations and the Graphics View Framework When you want to animate \l{QGraphicsItem}s, you also use - QPropertyAnimation. But, unfortunetly, QGraphicsItem does not - inherit QObject. A good solution is to subclass the graphics item - you wish to animate. This class will then also inherit QObject. + QPropertyAnimation. However, QGraphicsItem does not inherit QObject. + A good solution is to subclass the graphics item you wish to animate. + This class will then also inherit QObject. This way, QPropertyAnimation can be used for \l{QGraphicsItem}s. The example below shows how this is done. Another possibility is to inherit QGraphicsWidget, which already is a QObject. @@ -326,7 +329,7 @@ When using a \l{The State Machine Framework}{state machine}, we have a special state, QAnimationState, that will play one or more animations. - + The QState::addAnimatedTransition() convenience function lets you associate an animation to a state transition. The function will create the QAnimationState for you, and insert it into the state diff --git a/doc/src/diagrams/animations-architecture.svg b/doc/src/diagrams/animations-architecture.svg new file mode 100644 index 0000000..0246510 --- /dev/null +++ b/doc/src/diagrams/animations-architecture.svg @@ -0,0 +1,351 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!-- Created with Inkscape (http://www.inkscape.org/) --> +<svg + xmlns:dc="http://purl.org/dc/elements/1.1/" + xmlns:cc="http://creativecommons.org/ns#" + xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" + xmlns:svg="http://www.w3.org/2000/svg" + xmlns="http://www.w3.org/2000/svg" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd" + xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape" + width="950.00006" + height="365.28983" + id="svg2" + sodipodi:version="0.32" + inkscape:version="0.46" + sodipodi:docname="animations-architecture.svg" + 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implementation of a basic function Web browser. + \section1 \l{Qt Examples#State Machine}{State Machine} + + Qt provides a powerful hierchical finite state machine through the Qt State + Machine classes. + + These examples demonstrate the fundamental aspects of implementing + Statecharts with Qt. + \section1 \l{Qt Examples#Qt for Embedded Linux}{Qt for Embedded Linux} \l{Qt Examples#Qt for Embedded Linux}{\inlineimage qt-embedded-examples.png diff --git a/doc/src/examples.qdoc b/doc/src/examples.qdoc index 06d7727..6603390 100644 --- a/doc/src/examples.qdoc +++ b/doc/src/examples.qdoc @@ -311,7 +311,12 @@ \section1 State Machine \list + \o \l{statemachine/eventtransitions}{Event Transitions}\raisedaster + \o \l{statemachine/factorial}{Factorial States}\raisedaster + \o \l{statemachine/pingpong}{Ping Pong States}\raisedaster \o \l{statemachine/trafficlight}{Traffic Light}\raisedaster + \o \l{statemachine/twowaybutton}{Two-way Button}\raisedaster + \o \l{statemachine/tankgame}{Tank Game}\raisedaster \endlist \section1 Threads diff --git a/doc/src/examples/eventtransitions.qdoc b/doc/src/examples/eventtransitions.qdoc new file mode 100644 index 0000000..3b956bb --- /dev/null +++ b/doc/src/examples/eventtransitions.qdoc @@ -0,0 +1,86 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \example statemachine/eventtransitions + \title Event Transitions Example + + The Event Transitions example shows how to use event transitions, a + feature of \l{The State Machine Framework}. + + \snippet examples/statemachine/eventtransitions/main.cpp 0 + + The \c Window class's constructors begins by creating a button. + + \snippet examples/statemachine/eventtransitions/main.cpp 1 + + Two states, \c s1 and \c s2, are created; upon entry they will assign + "Outside" and "Inside" to the button's text, respectively. + + \snippet examples/statemachine/eventtransitions/main.cpp 2 + + When the button receives an event of type QEvent::Enter and the state + machine is in state \c s1, the machine will transition to state \c s2. + + \snippet examples/statemachine/eventtransitions/main.cpp 3 + + When the button receives an event of type QEvent::Leave and the state + machine is in state \c s2, the machine will transition back to state \c + s1. + + \snippet examples/statemachine/eventtransitions/main.cpp 4 + + Next, the state \c s3 is created. \c s3 will be entered when the button + receives an event of type QEvent::MouseButtonPress and the state machine + is in state \c s2. When the button receives an event of type + QEvent::MouseButtonRelease and the state machine is in state \c s3, the + machine will transition back to state \c s2. + + \snippet examples/statemachine/eventtransitions/main.cpp 5 + + Finally, the states are added to the machine as top-level states, the + initial state is set to be \c s1 ("Outside"), and the machine is started. + + \snippet examples/statemachine/eventtransitions/main.cpp 6 + + The main() function constructs a Window object and shows it. + +*/ diff --git a/doc/src/examples/factorial.qdoc b/doc/src/examples/factorial.qdoc new file mode 100644 index 0000000..2a72e0a --- /dev/null +++ b/doc/src/examples/factorial.qdoc @@ -0,0 +1,102 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \example statemachine/factorial + \title Factorial States Example + + The Factorial States example shows how to use \l{The State Machine + Framework} to calculate the factorial of an integer. + + The statechart for calculating the factorial looks as follows: + + \img factorial-example.png + \omit + \caption This is a caption + \endomit + + In other words, the state machine calculates the factorial of 6 and prints + the result. + + \snippet examples/statemachine/factorial/main.cpp 0 + + The Factorial class is used to hold the data of the computation, \c x and + \c fac. It also provides a signal that's emitted whenever the value of \c + x changes. + + \snippet examples/statemachine/factorial/main.cpp 1 + + The FactorialLoopTransition class implements the guard (\c x > 1) and + calculations (\c fac = \c x * \c fac; \c x = \c x - 1) of the factorial + loop. + + \snippet examples/statemachine/factorial/main.cpp 2 + + The FactorialDoneTransition class implements the guard (\c x <= 1) that + terminates the factorial computation. It also prints the final result to + standard output. + + \snippet examples/statemachine/factorial/main.cpp 3 + + The application's main() function first creates the application object, a + Factorial object and a state machine. + + \snippet examples/statemachine/factorial/main.cpp 4 + + The \c compute state is created, and the initial values of \c x and \c fac + are defined. A FactorialLoopTransition object is created and added to the + state. + + \snippet examples/statemachine/factorial/main.cpp 5 + + A final state, \c done, is created, and a FactorialDoneTransition object + is created with \c done as its target state. The transition is then added + to the \c compute state. + + \snippet examples/statemachine/factorial/main.cpp 6 + + The machine's initial state is set to be the \c compute state. We connect + the QStateMachine::finished() signal to the QCoreApplication::quit() slot, + so the application will quit when the state machine's work is + done. Finally, the state machine is started, and the application's event + loop is entered. + + */ diff --git a/doc/src/examples/pingpong.qdoc b/doc/src/examples/pingpong.qdoc new file mode 100644 index 0000000..040e429 --- /dev/null +++ b/doc/src/examples/pingpong.qdoc @@ -0,0 +1,107 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \example statemachine/pingpong + \title Ping Pong States Example + + The Ping Pong States example shows how to use parallel states together + with custom events and transitions in \l{The State Machine Framework}. + + This example implements a statechart where two states communicate by + posting events to the state machine. The state chart looks as follows: + + \img pingpong-example.png + \omit + \caption This is a caption + \endomit + + The \c pinger and \c ponger states are parallel states, i.e. they are + entered simultaneously and will take transitions independently of + eachother. + + The \c pinger state will post the first \c ping event upon entry; the \c + ponger state will respond by posting a \c pong event; this will cause the + \c pinger state to post a new \c ping event; and so on. + + \snippet examples/statemachine/pingpong/main.cpp 0 + + Two custom events are defined, \c PingEvent and \c PongEvent. + + \snippet examples/statemachine/pingpong/main.cpp 1 + + The \c Pinger class defines a state that posts a \c PingEvent to the state + machine when the state is entered. + + \snippet examples/statemachine/pingpong/main.cpp 2 + + The \c PingTransition class defines a transition that is triggered by + events of type \c PingEvent, and that posts a \c PongEvent (with a delay + of 500 milliseconds) to the state machine when the transition is + triggered. + + \snippet examples/statemachine/pingpong/main.cpp 3 + + The \c PongTransition class defines a transition that is triggered by + events of type \c PongEvent, and that posts a \c PingEvent (with a delay + of 500 milliseconds) to the state machine when the transition is + triggered. + + \snippet examples/statemachine/pingpong/main.cpp 4 + + The main() function begins by creating a state machine and a parallel + state group. + + \snippet examples/statemachine/pingpong/main.cpp 5 + + Next, the \c pinger and \c ponger states are created, with the parallel + state group as their parent state. Note that the transitions are \e + targetless. When such a transition is triggered, the source state won't be + exited and re-entered; only the transition's onTransition() function will + be called, and the state machine's configuration will remain the same, + which is precisely what we want in this case. + + \snippet examples/statemachine/pingpong/main.cpp 6 + + Finally, the group is added to the state machine, the machine is started, + and the application event loop is entered. + + */ diff --git a/doc/src/examples/tankgame.qdoc b/doc/src/examples/tankgame.qdoc new file mode 100644 index 0000000..ab3e0f4 --- /dev/null +++ b/doc/src/examples/tankgame.qdoc @@ -0,0 +1,117 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \example statemachine/tankgame + \title Tank Game Example + + The Tank Game example is part of the in \l{The State Machine Framework}. It shows how to use + parallel states to implement artificial intelligence controllers that run in parallel, and error + states to handle run-time errors in parts of the state graph created by external plugins. + + \image tankgame-example.png + + In this example we write a simple game. The application runs a state machine with two main + states: A "stopped" state and a "running" state. The user can load plugins from the disk by + selecting the "Add tank" menu item. + + When the "Add tank" menu item is selected, the "plugins" subdirectory in the example's + directory is searched for compatible plugins. If any are found, they will be listed in a + dialog box created using QInputDialog::getItem(). + + \snippet examples/statemachine/tankgame/mainwindow.cpp 1 + + If the user selects a plugin, the application will construct a TankItem object, which inherits + from QGraphicsItem and QObject, and which implements an agreed-upon interface using the + meta-object mechanism. + + \snippet examples/statemachine/tankgame/tankitem.h 0 + + The tank item will be passed to the plugin's create() function. This will in turn return a + QState object which is expected to implement an artificial intelligence which controls the + tank and attempts to destroy other tanks it detects. + + \snippet examples/statemachine/tankgame/mainwindow.cpp 2 + + Each returned QState object becomes a descendant of a \c region in the "running" state, which is + defined as a parallel state. This means that entering the "running" state will cause each of the + plugged-in QState objects to be entered simultaneously, allowing the tanks to run independently + of each other. + + \snippet examples/statemachine/tankgame/mainwindow.cpp 0 + + The maximum number of tanks on the map is four, and when this number is reached, the + "Add tank" menu item should be disabled. This is implemented by giving the "stopped" state two + children which define whether the map is full or not. + + \snippet examples/statemachine/tankgame/mainwindow.cpp 5 + + To make sure that we go into the correct child state when returning from the "running" state + (if the "Stop game" menu item is selected while the game is running) we also give the "stopped" + state a history state which we make the initial state of "stopped" state. + + \snippet examples/statemachine/tankgame/mainwindow.cpp 3 + + Since part of the state graph is defined by external plugins, we have no way of controlling + whether they contain errors. By default, run-time errors are handled in the state machine by + entering a top level state which prints out an error message and never exits. If we were to + use this default behavior, a run-time error in any of the plugins would cause the "running" + state to exit, and thus all the other tanks to stop running as well. A better solution would + be if the broken plugin was disabled and the rest of the tanks allowed to continue as before. + + This is done by setting the error state of the plugin's top-most state to a special error state + defined specifically for the plugin in question. + + \snippet examples/statemachine/tankgame/mainwindow.cpp 4 + + If a run-time error occurs in \c pluginState or any of its descendants, the state machine will + search the hierarchy of ancestors until it finds a state whose error state is different from + \c null. (Note that if we are worried that a plugin could inadvertedly be overriding our + error state, we could search the descendants of \c pluginState and verify that their error + states are set to \c null before accepting the plugin.) + + The specialized \c errorState sets the "enabled" property of the tank item in question to false, + causing it to be painted with a red cross over it to indicate that it is no longer running. + Since the error state is a child of the same region in the parallel "running" state as + \c pluginState, it will not exit the "running" state, and the other tanks will continue running + without disruption. + +*/ diff --git a/doc/src/examples/trafficlight.qdoc b/doc/src/examples/trafficlight.qdoc index 16ee8ad..ae62127 100644 --- a/doc/src/examples/trafficlight.qdoc +++ b/doc/src/examples/trafficlight.qdoc @@ -1,11 +1,41 @@ /**************************************************************************** ** -** Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies). +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). ** Contact: Qt Software Information (qt-info@nokia.com) ** -** This file is part of the $MODULE$ of the Qt Toolkit. +** This file is part of the documentation of the Qt Toolkit. ** -** $TROLLTECH_DUAL_LICENSE$ +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ ** ****************************************************************************/ @@ -26,30 +56,41 @@ \snippet examples/statemachine/trafficlight/main.cpp 0 The LightWidget class represents a single light of the traffic light. It - provides a setOn() function to turn the light on or off. It paints itself - in the color that's passed to the constructor. + provides an \c on property and two slots, turnOn() and turnOff(), to turn + the light on and off, respectively. The widget paints itself in the color + that's passed to the constructor. - \snippet examples/statemachine/trafficlight/main.cpp 2 + \snippet examples/statemachine/trafficlight/main.cpp 1 The TrafficLightWidget class represents the visual part of the traffic - light; it's a widget that contains three lights, and provides accessor - functions for these. + light; it's a widget that contains three lights arranged vertically, and + provides accessor functions for these. - \snippet examples/statemachine/trafficlight/main.cpp 1 + \snippet examples/statemachine/trafficlight/main.cpp 2 - The LightState class represents a state that turns a light on when the - state is entered, and off when the state is exited. The class is a timer, - and as we shall see the timeout is used to transition from one LightState - to another. + The createLightState() function creates a state that turns a light on when + the state is entered, and off when the state is exited. The state uses a + timer, and as we shall see the timeout is used to transition from one + LightState to another. Here is the statechart for the light state: + + \img trafficlight-example1.png + \omit + \caption This is a caption + \endomit \snippet examples/statemachine/trafficlight/main.cpp 3 - The TrafficLight class combines the TrafficLightWidget with control flow - based on the LightState class. The state graph has four states: - red-to-yellow, yellow-to-green, green-to-yellow and yellow-to-red. The - initial state is red-to-yellow; when the state's timer times out, the - state machine transitions to yellow-to-green. The same process repeats - through the other states. + The TrafficLight class combines the TrafficLightWidget with a state + machine. The state graph has four states: red-to-yellow, yellow-to-green, + green-to-yellow and yellow-to-red. The initial state is red-to-yellow; + when the state's timer times out, the state machine transitions to + yellow-to-green. The same process repeats through the other states. + This is what the statechart looks like: + + \img trafficlight-example2.png + \omit + \caption This is a caption + \endomit \snippet examples/statemachine/trafficlight/main.cpp 4 diff --git a/doc/src/examples/twowaybutton.qdoc b/doc/src/examples/twowaybutton.qdoc new file mode 100644 index 0000000..87de2e8 --- /dev/null +++ b/doc/src/examples/twowaybutton.qdoc @@ -0,0 +1,82 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \example statemachine/twowaybutton + \title Two-way Button Example + + The Two-way button example shows how to use \l{The State Machine + Framework} to implement a simple state machine that toggles the current + state when a button is clicked. + + \snippet examples/statemachine/twowaybutton/main.cpp 0 + + The application's main() function begins by constructing the application + object, a button and a state machine. + + \snippet examples/statemachine/twowaybutton/main.cpp 1 + + The state machine has two states; \c on and \c off. When either state is + entered, the text of the button will be set accordingly. + + \snippet examples/statemachine/twowaybutton/main.cpp 2 + + When the state machine is in the \c off state and the button is clicked, + it will transition to the \c on state; when the state machine is in the \c + on state and the button is clicked, it will transition to the \c off + state. + + \snippet examples/statemachine/twowaybutton/main.cpp 3 + + The states are added to the state machine; they become top-level (sibling) + states. + + \snippet examples/statemachine/twowaybutton/main.cpp 4 + + The initial state is \c off; this is the state the state machine will + immediately transition to once the state machine is started. + + \snippet examples/statemachine/twowaybutton/main.cpp 5 + + Finally, the button is resized and made visible, and the application event + loop is entered. + +*/ diff --git a/doc/src/groups.qdoc b/doc/src/groups.qdoc index 0411c3a..3c4da53 100644 --- a/doc/src/groups.qdoc +++ b/doc/src/groups.qdoc @@ -69,14 +69,14 @@ */ /*! - \group animations + \group animation \ingroup groups \title Animation Framework \brief Classes for animations, states and transitions. These classes provide a framework for creating both simple and complex - animations. The Animation Framework also provides states and animated + animations. \l{The Animation Framework} also provides states and animated transitions, making it easy to create animated stateful forms. */ diff --git a/doc/src/images/animations-architecture.png b/doc/src/images/animations-architecture.png Binary files differnew file mode 100644 index 0000000..9b581af --- /dev/null +++ b/doc/src/images/animations-architecture.png diff --git a/doc/src/images/factorial-example.png b/doc/src/images/factorial-example.png Binary files differnew file mode 100644 index 0000000..8fb1cc6 --- /dev/null +++ b/doc/src/images/factorial-example.png diff --git a/doc/src/images/pingpong-example.png b/doc/src/images/pingpong-example.png Binary files differnew file mode 100644 index 0000000..af707e4 --- /dev/null +++ b/doc/src/images/pingpong-example.png diff --git a/doc/src/images/statemachine-button-history.png b/doc/src/images/statemachine-button-history.png Binary files differindex cd66478..7f51cae 100644 --- a/doc/src/images/statemachine-button-history.png +++ b/doc/src/images/statemachine-button-history.png diff --git a/doc/src/images/statemachine-button-nested.png b/doc/src/images/statemachine-button-nested.png Binary files differindex 60360d1..762ac14 100644 --- a/doc/src/images/statemachine-button-nested.png +++ b/doc/src/images/statemachine-button-nested.png diff --git a/doc/src/images/statemachine-button.png b/doc/src/images/statemachine-button.png Binary files differindex 75d9e53..10102bd 100644 --- a/doc/src/images/statemachine-button.png +++ b/doc/src/images/statemachine-button.png diff --git a/doc/src/images/statemachine-customevents.png b/doc/src/images/statemachine-customevents.png Binary files differnew file mode 100644 index 0000000..62a4222 --- /dev/null +++ b/doc/src/images/statemachine-customevents.png diff --git a/doc/src/images/statemachine-customevents2.png b/doc/src/images/statemachine-customevents2.png Binary files differnew file mode 100644 index 0000000..57b37ef --- /dev/null +++ b/doc/src/images/statemachine-customevents2.png diff --git a/doc/src/images/statemachine-finished.png b/doc/src/images/statemachine-finished.png Binary files differindex 802621e..0ac081d 100644 --- a/doc/src/images/statemachine-finished.png +++ b/doc/src/images/statemachine-finished.png diff --git a/doc/src/images/statemachine-nonparallel.png b/doc/src/images/statemachine-nonparallel.png Binary files differindex 1fe60d8..f9850a7 100644 --- a/doc/src/images/statemachine-nonparallel.png +++ b/doc/src/images/statemachine-nonparallel.png diff --git a/doc/src/images/statemachine-parallel.png b/doc/src/images/statemachine-parallel.png Binary files differindex 1868792..a65c297 100644 --- a/doc/src/images/statemachine-parallel.png +++ b/doc/src/images/statemachine-parallel.png diff --git a/doc/src/images/tankgame-example.png b/doc/src/images/tankgame-example.png Binary files differnew file mode 100644 index 0000000..9e17e30 --- /dev/null +++ b/doc/src/images/tankgame-example.png diff --git a/doc/src/images/trafficlight-example1.png b/doc/src/images/trafficlight-example1.png Binary files differnew file mode 100644 index 0000000..ec8c7ff --- /dev/null +++ b/doc/src/images/trafficlight-example1.png diff --git a/doc/src/images/trafficlight-example2.png b/doc/src/images/trafficlight-example2.png Binary files differnew file mode 100644 index 0000000..a12e4db --- /dev/null +++ b/doc/src/images/trafficlight-example2.png diff --git a/doc/src/statemachine.qdoc b/doc/src/statemachine.qdoc index 60ae815..5a89f4d 100644 --- a/doc/src/statemachine.qdoc +++ b/doc/src/statemachine.qdoc @@ -1,11 +1,41 @@ /**************************************************************************** ** -** Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies). +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). ** Contact: Qt Software Information (qt-info@nokia.com) ** -** This file is part of the $MODULE$ of the Qt Toolkit. +** This file is part of the documentation of the Qt Toolkit. ** -** $TROLLTECH_DUAL_LICENSE$ +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ ** ****************************************************************************/ @@ -13,6 +43,7 @@ \page statemachine-api.html \title The State Machine Framework \brief An overview of the State Machine framework for constructing and executing state graphs. + \ingroup architecture \tableofcontents @@ -33,10 +64,10 @@ The State Machine framework provides an API and execution model that can be used to effectively embed the elements and semantics of statecharts in Qt - applications. The framework integrates tightly with Qt's existing event - system and meta-object system; for example, transitions between states can - be triggered by signals, and states can be configured to set properties and - invoke methods on QObjects. + applications. The framework integrates tightly with Qt's meta-object system; + for example, transitions between states can be triggered by signals, and + states can be configured to set properties and invoke methods on QObjects. + Qt's event system is used to drive the state machines. \section1 A Simple State Machine @@ -52,34 +83,49 @@ \endomit The following snippet shows the code needed to create such a state machine. + First, we create the state machine and states: \code QStateMachine machine; QState *s1 = new QState(); QState *s2 = new QState(); QState *s3 = new QState(); + \endcode + + Then, we create the transitions by using the QState::addTransition() + function: + \code s1->addTransition(button, SIGNAL(clicked()), s2); s2->addTransition(button, SIGNAL(clicked()), s3); s3->addTransition(button, SIGNAL(clicked()), s1); + \endcode + + Next, we add the states to the machine and set the machine's initial state: + \code machine.addState(s1); machine.addState(s2); machine.addState(s3); machine.setInitialState(s1); + \endcode + + Finally, we start the state machine: + \code machine.start(); \endcode - Once the state machine has been set up, you need to start it by calling - QStateMachine::start(). The state machine executes asynchronously, i.e. it - becomes part of your application's event loop. + The state machine executes asynchronously, i.e. it becomes part of your + application's event loop. + + \section1 Doing Useful Work on State Entry and Exit - The above state machine is perfectly fine, but it doesn't \e do anything; it - merely transitions from one state to another. The QState::assignProperty() - function can be used to have a state set a property of a QObject when the - state is entered. In the following snippet, the value that should be - assigned to a QLabel's text property is specified for each state: + The above state machine merely transitions from one state to another, it + doesn't perform any operations. The QState::assignProperty() function can be + used to have a state set a property of a QObject when the state is + entered. In the following snippet, the value that should be assigned to a + QLabel's text property is specified for each state: \code s1->assignProperty(label, "text", "In state s1"); @@ -90,20 +136,32 @@ When any of the states is entered, the label's text will be changed accordingly. - The QActionState::entered() signal is emitted when the state is entered. In the + The QState::entered() signal is emitted when the state is entered, and the + QState::exited() signal is emitted when the state is exited. In the following snippet, the button's showMaximized() slot will be called when - state \c s3 is entered: + state \c s3 is entered, and the button's showMinimized() slot will be called + when \c s3 is exited: \code QObject::connect(s3, SIGNAL(entered()), button, SLOT(showMaximized())); + QObject::connect(s3, SIGNAL(exited()), button, SLOT(showMinimized())); \endcode - \section1 Sharing Transitions By Grouping States + Custom states can reimplement QAbstractState::onEntry() and + QAbstractState::onExit(). + + \section1 State Machines That Finish The state machine defined in the previous section never finishes. In order for a state machine to be able to finish, it needs to have a top-level \e - final state. When the state machine enters a top-level final state, the - machine will emit the finished() signal and halt. + final state (QFinalState object). When the state machine enters a top-level + final state, the machine will emit the QStateMachine::finished() signal and + halt. + + All you need to do to introduce a final state in the graph is create a + QFinalState object and use it as the target of one or more transitions. + + \section1 Sharing Transitions By Grouping States Assume we wanted the user to be able to quit the application at any time by clicking a Quit button. In order to achieve this, we need to create a final @@ -165,6 +223,9 @@ s12>addTransition(quitButton, SIGNAL(clicked()), s12); \endcode + A transition can have any state as its target, i.e. the target state does + not have to be on the same level in the state hierarchy as the source state. + \section1 Using History States to Save and Restore the Current State Imagine that we wanted to add an "interrupt" mechanism to the example @@ -251,19 +312,334 @@ QState *s12 = new QState(s1); \endcode + When a parallel state group is entered, all its child states will be + simultaneously entered. Transitions within the individual child states + operate normally. However, any of the child states may take a transition + outside the parent state. When this happens, the parent state and all of its + child states are exited. + \section1 Detecting that a Composite State has Finished - A child state can be final; when a final child state is entered, the parent - state emits the QState::finished() signal. + A child state can be final (a QFinalState object); when a final child state + is entered, the parent state emits the QState::finished() signal. The + following diagram shows a composite state \c s1 which does some processing + before entering a final state: \img statemachine-finished.png \omit \caption This is a caption \endomit - This is useful when you want to hide the internal details of a state; - i.e. the only thing the outside world should be able to do is enter the - state, and get a notification when the state has finished (i.e. when a final - child state has been entered). + When \c s1 's final state is entered, \c s1 will automatically emit + finished(). We use a signal transition to cause this event to trigger a + state change: + + \code + s1->addTransition(s1, SIGNAL(finished()), s2); + \endcode + + Using final states in composite states is useful when you want to hide the + internal details of a composite state; i.e. the only thing the outside world + should be able to do is enter the state, and get a notification when the + state has completed its work. This is a very powerful abstraction and + encapsulation mechanism when building complex (deeply nested) state + machines. (In the above example, you could of course create a transition + directly from \c s1 's \c done state rather than relying on \c s1 's + finished() signal, but with the consequence that implementation details of + \c s1 are exposed and depended on). + + For parallel state groups, the QState::finished() signal is emitted when \e + all the child states have entered final states. + + \section1 Events, Transitions and Guards + + A QStateMachine runs its own event loop. For signal transitions + (QSignalTransition objects), QStateMachine automatically posts a + QSignalEvent to itself when it intercepts the corresponding signal; + similarly, for QObject event transitions (QEventTransition objects) a + QWrappedEvent is posted. + + You can post your own events to the state machine using + QStateMachine::postEvent(). + + When posting a custom event to the state machine, you typically also have + one or more custom transitions that can be triggered from events of that + type. To create such a transition, you subclass QAbstractTransition and + reimplement QAbstractTransition::eventTest(), where you check if an event + matches your event type (and optionally other criteria, e.g. attributes of + the event object). + + Here we define our own custom event type, \c StringEvent, for posting + strings to the state machine: + + \code + struct StringEvent : public QEvent + { + StringEvent(const QString &val) + : QEvent(QEvent::Type(QEvent::User+1)), + value(val) {} + + QString value; + }; + \endcode + + Next, we define a transition that only triggers when the event's string + matches a particular string (a \e guarded transition): + + \code + class StringTransition : public QAbstractTransition + { + public: + StringTransition(const QString &value) + : m_value(value) {} + + protected: + virtual bool eventTest(QEvent *e) const + { + if (e->type() != QEvent::Type(QEvent::User+1)) // StringEvent + return false; + StringEvent *se = static_cast<StringEvent*>(e); + return (m_value == se->value); + } + + virtual void onTransition(QEvent *) {} + + private: + QString m_value; + }; + \endcode + + In the eventTest() reimplementation, we first check if the event type is the + desired one; if so, we cast the event to a StringEvent and perform the + string comparison. + + The following is a statechart that uses the custom event and transition: + + \img statemachine-customevents.png + \omit + \caption This is a caption + \endomit + + Here's what the implementation of the statechart looks like: + + \code + QStateMachine machine; + QState *s1 = new QState(); + QState *s2 = new QState(); + QFinalState *done = new QFinalState(); + + StringTransition *t1 = new StringTransition("Hello"); + t1->setTargetState(s2); + s1->addTransition(t1); + StringTransition *t2 = new StringTransition("world"); + t2->setTargetState(done); + s2->addTransition(t2); + + machine.addState(s1); + machine.addState(s2); + machine.addState(done); + machine.setInitialState(s1); + \endcode + + Once the machine is started, we can post events to it. + + \code + machine.postEvent(new StringEvent("Hello")); + machine.postEvent(new StringEvent("world")); + \endcode + + An event that is not handled by any relevant transition will be silently + consumed by the state machine. It can be useful to group states and provide + a default handling of such events; for example, as illustrated in the + following statechart: + + \img statemachine-customevents2.png + \omit + \caption This is a caption + \endomit - */ + For deeply nested statecharts, you can add such "fallback" transitions at + the level of granularity that's most appropriate. + + \section1 Using Restore Policy To Automatically Restore Properties + + In some state machines it can be useful to focus the attention on assigning properties in states, + not on restoring them when the state is no longer active. If you know that a property should + always be restored to its initial value when the machine enters a state that does not explicitly + give the property a value, you can set the global restore policy to + QStateMachine::RestoreProperties. + + \code + QStateMachine machine; + machine.setGlobalRestorePolicy(QStateMachine::RestoreProperties); + \endcode + + When this restore policy is set, the machine will automatically restore all properties. If it + enters a state where a given property is not set, it will first search the hierarchy of ancestors + to see if the property is defined there. If it is, the property will be restored to the value + defined by the closest ancestor. If not, it will be restored to its initial value (i.e. the + value of the property before any property assignments in states were executed.) + + Take the following code: + \code + QStateMachine machine; + machine.setGlobalRestorePolicy(QStateMachine::RestoreProperties); + + QState *s1 = new QState(); + s1->assignProperty(object, "fooBar", 1.0); + machine.addState(s1); + machine.setInitialState(s1); + + QState *s2 = new QState(); + machine.addState(s2); + \endcode + + Lets say the property \c fooBar is 0.0 when the machine starts. When the machine is in state + \c s1, the property will be 1.0, since the state explicitly assigns this value to it. When the + machine is in state \c s2, no value is explicitly defined for the property, so it will implicitly + be restored to 0.0. + + If we are using nested states, the parent defines a value for the property which is inherited by + all descendants that do not explicitly assign a value to the property. + \code + QStateMachine machine; + machine.setGlobalRestorePolicy(QStateMachine::RestoreProperties); + + QState *s1 = new QState(); + s1->assignProperty(object, "fooBar", 1.0); + machine.addState(s1); + machine.setInitialState(s1); + + QState *s2 = new QState(s1); + s2->assignProperty(object, "fooBar", 2.0); + s1->setInitialState(s2); + + QState *s3 = new QState(s1); + \endcode + + Here \c s1 has two children: \c s2 and \c s3. When \c s2 is entered, the property \c fooBar + will have the value 2.0, since this is explicitly defined for the state. When the machine is in + state \c s3, no value is defined for the state, but \c s1 defines the property to be 1.0, so this + is the value that will be assigned to \c fooBar. + + \section1 Animating Property Assignments + + The State Machine API connects with the Animation API in Qt to allow automatically animating + properties as they are assigned in states. + + Say we have the following code: + \code + QState *s1 = new QState(); + QState *s2 = new QState(); + + s1->assignProperty(button, "geometry", QRectF(0, 0, 50, 50)); + s2->assignProperty(button, "geometry", QRectF(0, 0, 100, 100)); + + s1->addTransition(button, SIGNAL(clicked()), s2); + \endcode + + Here we define two states of a user interface. In \c s1 the \c button is small, and in \c s2 + it is bigger. If we click the button to transition from \c s1 to \c s2, the geometry of the button + will be set immediately when a given state has been entered. If we want the transition to be + smooth, however, all we need to do is make a QPropertyAnimation and add this to the transition + object. + + \code + QState *s1 = new QState(); + QState *s2 = new QState(); + + s1->assignProperty(button, "geometry", QRectF(0, 0, 50, 50)); + s2->assignProperty(button, "geometry", QRectF(0, 0, 100, 100)); + + QSignalTransition *transition = s1->addTransition(button, SIGNAL(clicked()), s2); + transition->addAnimation(new QPropertyAnimation(button, "geometry")); + \endcode + + Adding an animation for the property in question means that the property assignment will no + longer take immediate effect when the state has been entered. Instead, the animation will start + playing when the state has been entered and smoothly animate the property assignment. Since we + do not set the start value or end value of the animation, these will be set implicitly. The + start value of the animation will be the property's current value when the animation starts, and + the end value will be set based on the property assignments defined for the state. + + If the global restore policy of the state machine is set to QStateMachine::RestoreProperties, + it is possible to also add animations for the property restorations. + + \section1 Detecting That All Properties Have Been Set In A State + + When animations are used to assign properties, a state no longer defines the exact values that a + property will have when the machine is in the given state. While the animation is running, the + property can potentially have any value, depending on the animation. + + In some cases, it can be useful to be able to detect when the property has actually been assigned + the value defined by a state. For this, we can use the state's polished() signal. + \code + QState *s1 = new QState(); + s1->assignProperty(button, "geometry", QRectF(0, 0, 50, 50)); + + QState *s2 = new QState(); + + s1->addTransition(s1, SIGNAL(polished()), s2); + \endcode + + The machine will be in state \c s1 until the \c geometry property has been set. Then it will + immediately transition into \c s2. If the transition into \c s1 has an animation for the \c + geometry property, then the machine will stay in \c s1 until the animation has finished. If there + is no animation, it will simply set the property and immediately enter state \c s2. + + Either way, when the machine is in state \c s2, the property \c geometry has been assigned the + defined value. + + If the global restore policy is set to QStateMachine::RestoreProperties, the state will not emit + the polished() signal until these have been executed as well. + + \section1 What happens if a state is exited before the animation has finished + + If a state has property assignments, and the transition into the state has animations for the + properties, the state can potentially be exited before the properties have been assigned to the + values defines by the state. This is true in particular when there are transitions out from the + state that do not depend on the state being polished, as described in the previous section. + + The State Machine API guarantees that a property assigned by the state machine either: + \list + \o Has a value explicitly assigned to the property. + \o Is currently being animated into a value explicitly assigned to the property. + \endlist + + When a state is exited prior to the animation finishing, the behavior of the state machine depends + on the target state of the transition. If the target state explicitly assigns a value to the + property, no additional action will be taken. The property will be assigned the value defined by + the target state. + + If the target state does not assign any value to the property, there are two + options: By default, the property will be assigned the value defined by the state it is leaving + (the value it would have been assigned if the animation had been permitted to finish playing.) If + a global restore policy is set, however, this will take precedence, and the property will be + restored as usual. + + \section1 Default Animations + + As described earlier, you can add animations to transitions to make sure property assignments + in the target state are animated. If you want a specific animation to be used for a given property + regardless of which transition is taken, you can add it as a default animation to the state + machine. This is in particular useful when the properties assigned (or restored) by specific + states is not known when the machine is constructed. + + \code + QState *s1 = new QState(); + QState *s2 = new QState(); + + s2->assignProperty(object, "fooBar", 2.0); + s1->addTransition(s2); + + QStateMachine machine; + machine.setInitialState(s1); + machine.addDefaultAnimation(new QPropertyAnimation(object, "fooBar")); + \endcode + + When the machine is in state \c s2, the machine will play the default animation for the + property \c fooBar since this property is assigned by \c s2. + + Note that animations explicitly set on transitions will take precedence over any default + animation for the given property. +*/ |
