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diff --git a/doc/src/qtquick1/behaviors-and-states.qdoc b/doc/src/qtquick1/behaviors-and-states.qdoc deleted file mode 100644 index 5d81246e49..0000000000 --- a/doc/src/qtquick1/behaviors-and-states.qdoc +++ /dev/null @@ -1,207 +0,0 @@ -/**************************************************************************** -** -** 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. -** -** -** -** -** -** $QT_END_LICENSE$ -** -****************************************************************************/ - -/*! -\page qml-behaviors-and-states.html -\inqmlmodule QtQuick 1 -\title Using QML Behaviors with States - -\section1 Using Behaviors with States - -In some cases you may choose to use a Behavior to animate a property change caused by a state change. While this works well for some situations, in other situations it may lead to unexpected behavior. - -Here's an example that shows the problem: - -\qml -import QtQuick 1.0 - -Rectangle { - width: 400 - height: 400 - - Rectangle { - id: coloredRect - width: 100 - height: 100 - anchors.centerIn: parent - - color: "red" - Behavior on color { - ColorAnimation {} - } - - MouseArea { - id: mouser - anchors.fill: parent - hoverEnabled: true - } - - states: State { - name: "GreenState" - when: mouser.containsMouse - - PropertyChanges { - target: coloredRect - color: "green" - } - } - } -} -\endqml - -Testing the example by quickly and repeatedly moving the mouse in to and out of the colored rectangle shows that the colored rectangle will settle into a green color over time, never returning to full red. This is not what we wanted! The -problem occurs because we have used a Behavior to animate the change in color, and our state change is trigged by the mouse entering or exiting the MouseArea, which is easily interrupted. - -To state the problem more formally, using States and Behaviors together can cause unexpected behavior when: -\list -\o a Behavior is used to animate a property change, specifically when moving from an explicitly defined state back to the implicit base state; and -\o this Behavior can be interrupted to (re-)enter an explicitly defined state. -\endlist - -The problem occurs because of the way the base state is defined for QML: as the "snapshot" state of the application just prior to entering an explicitly defined state. In this case, if we are in the process of animating from green back -to red, and interrupt the animation to return to "GreenState", the base state will include the color in its intermediate, mid-animation form. - -While future versions of QML should be able to handle this situation more gracefully, there are currently several ways to rework your application to avoid this problem. - -1. Use a transition to animate the change, rather than a Behavior. - -\qml -import QtQuick 1.0 - -Rectangle { - width: 400 - height: 400 - - Rectangle { - id: coloredRect - width: 100 - height: 100 - anchors.centerIn: parent - - color: "red" - - MouseArea { - id: mouser - anchors.fill: parent - hoverEnabled: true - } - - states: State { - name: "GreenState" - when: mouser.containsMouse - - PropertyChanges { - target: coloredRect - color: "green" - } - } - - transitions: Transition { - ColorAnimation {} - } - } -} -\endqml - -2. Use a conditional binding to change the property value, rather than a state - -\qml -import QtQuick 1.0 - -Rectangle { - width: 400 - height: 400 - - Rectangle { - id: coloredRect - width: 100 - height: 100 - anchors.centerIn: parent - - color: mouser.containsMouse ? "green" : "red" - Behavior on color { - ColorAnimation {} - } - - MouseArea { - id: mouser - anchors.fill: parent - hoverEnabled: true - } - } -} -\endqml - -3. Use only explicitly defined states, rather than an implicit base state - -\qml -import QtQuick 1.0 - -Rectangle { - width: 400 - height: 400 - - Rectangle { - id: coloredRect - width: 100 - height: 100 - anchors.centerIn: parent - - Behavior on color { - ColorAnimation {} - } - - MouseArea { - id: mouser - anchors.fill: parent - hoverEnabled: true - } - - states: [ - State { - name: "GreenState" - when: mouser.containsMouse - - PropertyChanges { - target: coloredRect - color: "green" - } - }, - State { - name: "RedState" - when: !mouser.containsMouse - - PropertyChanges { - target: coloredRect - color: "red" - } - }] - } -} -\endqml - -*/ |