Fixes QPropertyAnimation's default start value update condition

The default start value is updated when the animation changes from
Stopped to Running state.

Reviewed-by: Jan-Arve

3 files changed, 38 insertions, 20 deletions

diff --git a/src/corelib/animation/qpropertyanimation.cpp b/src/corelib/animation/qpropertyanimation.cpp
index edcabaa..9a0c5bc 100644
--- a/src/corelib/animation/qpropertyanimation.cpp
+++ b/src/corelib/animation/qpropertyanimation.cpp
@@ -49,7 +49,7 @@
     by itself as a simple animation class, or as part of more complex
     animations through QAnimationGroup.
 
-    The most common way to use QPropertyAnimation is to construct an instance 
+    The most common way to use QPropertyAnimation is to construct an instance
     of it by passing a pointer to a QObject or a QWidget, and the name of the
     property you would like to animate to QPropertyAnimation's constructor.
 
@@ -220,11 +220,20 @@ void QPropertyAnimation::updateCurrentValue(const QVariant &value)
 
 /*!
     \reimp
+
+    If the startValue is not defined when the state of the animation changes from Stopped to Running,
+    the current property value is used as the initial value for the animation.
 */
 void QPropertyAnimation::updateState(QAbstractAnimation::State oldState,
                                      QAbstractAnimation::State newState)
 {
     Q_D(QPropertyAnimation);
+
+    if (!d->target) {
+        qWarning("QPropertyAnimation::updateState: Changing state of an animation without target");
+        return;
+    }
+
     QVariantAnimation::updateState(oldState, newState);
     QMutexLocker locker(guardHashLock());
     QPropertyAnimationHash * hash = _q_runningAnimations();
@@ -235,20 +244,19 @@ void QPropertyAnimation::updateState(QAbstractAnimation::State oldState,
         if (oldAnim) {
             // try to stop the top level group
             QAbstractAnimation *current = oldAnim;
-            while(current->group() && current->state() != Stopped) current = current->group();
+            while (current->group() && current->state() != Stopped)
+                current = current->group();
             current->stop();
         }
         hash->insert(key, this);
-        // Initialize start value
-        // ### review this line below, d->atEnd() ?
-        // ### avoid entering a state where start value is not set
-        if (d->target && (d->atBeginning() || d->atEnd())) {
+
+        // update the default start value
+        if (oldState == Stopped) {
             d->setDefaultStartValue(d->target->property(d->propertyName.constData()));
         }
     } else if (hash->value(key) == this) {
         hash->remove(key);
     }
-
 }
 
 #include "moc_qpropertyanimation.cpp"
diff --git a/src/corelib/animation/qvariantanimation_p.h b/src/corelib/animation/qvariantanimation_p.h
index 66910c1..14a3ef6 100644
--- a/src/corelib/animation/qvariantanimation_p.h
+++ b/src/corelib/animation/qvariantanimation_p.h
@@ -88,18 +88,6 @@ public:
         return q->d_func();
     }
 
-    
-    //some helper functions
-    bool atBeginning() const
-    {
-        return currentTime == 0;
-    }
-
-    bool atEnd() const
-    {
-        return currentTime == duration && currentLoop == (loopCount - 1);
-    }
-
     void setDefaultStartValue(const QVariant &value);
 
     int duration;
@@ -109,7 +97,7 @@ public:
     QVariant currentValue;
     QVariant defaultStartValue;
     bool hasStartValue;
-   
+
     //this is used to keep track of the KeyValue interval in which we currently are
     struct
     {
diff --git a/tests/auto/qpropertyanimation/tst_qpropertyanimation.cpp b/tests/auto/qpropertyanimation/tst_qpropertyanimation.cpp
index 437c862..f0deab5 100644
--- a/tests/auto/qpropertyanimation/tst_qpropertyanimation.cpp
+++ b/tests/auto/qpropertyanimation/tst_qpropertyanimation.cpp
@@ -84,6 +84,7 @@ private slots:
     void deletion3();
     void duration0();
     void noStartValue();
+    void noStartValueWithLoop();
     void startWhenAnotherIsRunning();
     void easingcurve_data();
     void easingcurve();
@@ -416,6 +417,27 @@ void tst_QPropertyAnimation::noStartValue()
     QCOMPARE(o.values.last(), 420);
 }
 
+void tst_QPropertyAnimation::noStartValueWithLoop()
+{
+    StartValueTester o;
+    o.setProperty("ole", 42);
+    o.values.clear();
+
+    QPropertyAnimation a(&o, "ole");
+    a.setEndValue(420);
+    a.setDuration(250);
+    a.setLoopCount(2);
+    a.start();
+
+    a.setCurrentTime(250);
+    QCOMPARE(o.values.first(), 42);
+    QCOMPARE(a.currentValue().toInt(), 42);
+    QCOMPARE(o.values.last(), 42);
+
+    a.setCurrentTime(500);
+    QCOMPARE(a.currentValue().toInt(), 420);
+}
+
 void tst_QPropertyAnimation::startWhenAnotherIsRunning()
 {
     StartValueTester o;