src/declarative/util/qdeclarativebehavior.cpp

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  41
  42 #include "private/qdeclarativebehavior_p.h"
  43
  44 #include "private/qdeclarativeanimation_p.h"
  45 #include "private/qdeclarativetransition_p.h"
  46
  47 #include <qdeclarativecontext.h>
  48 #include <qdeclarativeinfo.h>
  49 #include <qdeclarativeproperty_p.h>
  50 #include <qdeclarativeguard_p.h>
  51 #include <qdeclarativeengine_p.h>
  52
  53 #include <private/qobject_p.h>
  54
  55 QT_BEGIN_NAMESPACE
  56
  57 class QDeclarativeBehaviorPrivate : public QObjectPrivate
  58 {
  59     Q_DECLARE_PUBLIC(QDeclarativeBehavior)
  60 public:
  61     QDeclarativeBehaviorPrivate() : animation(0), enabled(true), finalized(false)
  62       , blockRunningChanged(false) {}
  63
  64     QDeclarativeProperty property;
  65     QVariant currentValue;
  66     QVariant targetValue;
  67     QDeclarativeGuard<QDeclarativeAbstractAnimation> animation;
  68     bool enabled;
  69     bool finalized;
  70     bool blockRunningChanged;
  71 };
  72
  73 /*!
  74     \qmlclass Behavior QDeclarativeBehavior
  75     \ingroup qml-animation-transition
  76     \since 4.7
  77     \brief The Behavior element allows you to specify a default animation for a property change.
  78
  79     A Behavior defines the default animation to be applied whenever a
  80     particular property value changes.
  81
  82     For example, the following Behavior defines a NumberAnimation to be run
  83     whenever the \l Rectangle's \c width value changes. When the MouseArea
  84     is clicked, the \c width is changed, triggering the behavior's animation:
  85
  86     \snippet doc/src/snippets/declarative/behavior.qml 0
  87
  88     Note that a property cannot have more than one assigned Behavior. To provide
  89     multiple animations within a Behavior, use ParallelAnimation or
  90     SequentialAnimation.
  91
  92     If a \l{QML States}{state change} has a \l Transition that matches the same property as a
  93     Behavior, the \l Transition animation overrides the Behavior for that
  94     state change. For general advice on using Behaviors to animate state changes, see
  95     \l{Using QML Behaviors with States}.
  96
  97     \sa {QML Animation and Transitions}, {declarative/animation/behaviors}{Behavior example}, QtDeclarative
  98 */
  99
 100
 101 QDeclarativeBehavior::QDeclarativeBehavior(QObject *parent)
 102     : QObject(*(new QDeclarativeBehaviorPrivate), parent)
 103 {
 104 }
 105
 106 QDeclarativeBehavior::~QDeclarativeBehavior()
 107 {
 108 }
 109
 110 /*!
 111     \qmlproperty Animation Behavior::animation
 112     \default
 113
 114     This property holds the animation to run when the behavior is triggered.
 115 */
 116
 117 QDeclarativeAbstractAnimation *QDeclarativeBehavior::animation()
 118 {
 119     Q_D(QDeclarativeBehavior);
 120     return d->animation;
 121 }
 122
 123 void QDeclarativeBehavior::setAnimation(QDeclarativeAbstractAnimation *animation)
 124 {
 125     Q_D(QDeclarativeBehavior);
 126     if (d->animation) {
 127         qmlInfo(this) << tr("Cannot change the animation assigned to a Behavior.");
 128         return;
 129     }
 130
 131     d->animation = animation;
 132     if (d->animation) {
 133         d->animation->setDefaultTarget(d->property);
 134         d->animation->setDisableUserControl();
 135         connect(d->animation->qtAnimation(),
 136                 SIGNAL(stateChanged(QAbstractAnimation::State,QAbstractAnimation::State)),
 137                 this,
 138                 SLOT(qtAnimationStateChanged(QAbstractAnimation::State,QAbstractAnimation::State)));
 139     }
 140 }
 141
 142
 143 void QDeclarativeBehavior::qtAnimationStateChanged(QAbstractAnimation::State newState,QAbstractAnimation::State)
 144 {
 145     Q_D(QDeclarativeBehavior);
 146     if (!d->blockRunningChanged)
 147         d->animation->notifyRunningChanged(newState == QAbstractAnimation::Running);
 148 }
 149
 150
 151 /*!
 152     \qmlproperty bool Behavior::enabled
 153
 154     This property holds whether the behavior will be triggered when the tracked
 155     property changes value.
 156
 157     By default a Behavior is enabled.
 158 */
 159
 160 bool QDeclarativeBehavior::enabled() const
 161 {
 162     Q_D(const QDeclarativeBehavior);
 163     return d->enabled;
 164 }
 165
 166 void QDeclarativeBehavior::setEnabled(bool enabled)
 167 {
 168     Q_D(QDeclarativeBehavior);
 169     if (d->enabled == enabled)
 170         return;
 171     d->enabled = enabled;
 172     emit enabledChanged();
 173 }
 174
 175 void QDeclarativeBehavior::write(const QVariant &value)
 176 {
 177     Q_D(QDeclarativeBehavior);
 178     qmlExecuteDeferred(this);
 179     if (!d->animation || !d->enabled || !d->finalized) {
 180         QDeclarativePropertyPrivate::write(d->property, value, QDeclarativePropertyPrivate::BypassInterceptor | QDeclarativePropertyPrivate::DontRemoveBinding);
 181         d->targetValue = value;
 182         return;
 183     }
 184
 185     if (d->animation->isRunning() && value == d->targetValue)
 186         return;
 187
 188     d->currentValue = d->property.read();
 189     d->targetValue = value;
 190
 191     if (d->animation->qtAnimation()->duration() != -1
 192             && d->animation->qtAnimation()->state() != QAbstractAnimation::Stopped) {
 193         d->blockRunningChanged = true;
 194         d->animation->qtAnimation()->stop();
 195     }
 196
 197     QDeclarativeStateOperation::ActionList actions;
 198     QDeclarativeAction action;
 199     action.property = d->property;
 200     action.fromValue = d->currentValue;
 201     action.toValue = value;
 202     actions << action;
 203
 204     QList<QDeclarativeProperty> after;
 205     d->animation->transition(actions, after, QDeclarativeAbstractAnimation::Forward);
 206     d->animation->qtAnimation()->start();
 207     d->blockRunningChanged = false;
 208     if (!after.contains(d->property))
 209         QDeclarativePropertyPrivate::write(d->property, value, QDeclarativePropertyPrivate::BypassInterceptor | QDeclarativePropertyPrivate::DontRemoveBinding);
 210 }
 211
 212 void QDeclarativeBehavior::setTarget(const QDeclarativeProperty &property)
 213 {
 214     Q_D(QDeclarativeBehavior);
 215     d->property = property;
 216     d->currentValue = property.read();
 217     if (d->animation)
 218         d->animation->setDefaultTarget(property);
 219
 220     QDeclarativeEnginePrivate *engPriv = QDeclarativeEnginePrivate::get(qmlEngine(this));
 221     engPriv->registerFinalizedParserStatusObject(this, this->metaObject()->indexOfSlot("componentFinalized()"));
 222 }
 223
 224 void QDeclarativeBehavior::componentFinalized()
 225 {
 226     Q_D(QDeclarativeBehavior);
 227     d->finalized = true;
 228 }
 229
 230 QT_END_NAMESPACE