Flicking behaviour of ListView/GridView SnapOnItem is inconsistent

Improve the response of the views when SnapOneItem/Row is enabled.
In this case it is best to be much more reactive to the user input
since even a small movement in a particular direction indicates
a change to the next/previous item.

Change-Id: I6a8eb689c3b12cdc67f24106032e36bba82d2846
Task-number: QTBUG-19874
Reviewed-by: Bea Lam
(cherry picked from commit e7bebcf0c59368340df524db4a53ae2595d057d7)

4 files changed, 196 insertions, 149 deletions

diff --git a/src/declarative/graphicsitems/qdeclarativeflickable.cpp b/src/declarative/graphicsitems/qdeclarativeflickable.cpp
index b8577e9..0a98c01 100644
--- a/src/declarative/graphicsitems/qdeclarativeflickable.cpp
+++ b/src/declarative/graphicsitems/qdeclarativeflickable.cpp
@@ -168,9 +168,7 @@ QDeclarativeFlickablePrivate::QDeclarativeFlickablePrivate()
   : contentItem(new QDeclarativeItem)
     , hData(this, &QDeclarativeFlickablePrivate::setRoundedViewportX)
     , vData(this, &QDeclarativeFlickablePrivate::setRoundedViewportY)
-    , flickingHorizontally(false), flickingVertically(false)
     , hMoved(false), vMoved(false)
-    , movingHorizontally(false), movingVertically(false)
     , stealMouse(false), pressed(false), interactive(true), calcVelocity(false)
     , deceleration(QML_FLICK_DEFAULTDECELERATION)
     , maxVelocity(QML_FLICK_DEFAULTMAXVELOCITY), reportedVelocitySmoothing(100)
@@ -294,18 +292,18 @@ void QDeclarativeFlickablePrivate::flick(AxisData &data, qreal minExtent, qreal
         else
             timeline.accel(data.move, v, deceleration, maxDistance);
         timeline.callback(QDeclarativeTimeLineCallback(&data.move, fixupCallback, this));
-        if (!flickingHorizontally && q->xflick()) {
-            flickingHorizontally = true;
+        if (!hData.flicking && q->xflick()) {
+            hData.flicking = true;
             emit q->flickingChanged();
             emit q->flickingHorizontallyChanged();
-            if (!flickingVertically)
+            if (!vData.flicking)
                 emit q->flickStarted();
         }
-        if (!flickingVertically && q->yflick()) {
-            flickingVertically = true;
+        if (!vData.flicking && q->yflick()) {
+            vData.flicking = true;
             emit q->flickingChanged();
             emit q->flickingVerticallyChanged();
-            if (!flickingHorizontally)
+            if (!hData.flicking)
                 emit q->flickStarted();
         }
     } else {
@@ -614,11 +612,11 @@ void QDeclarativeFlickable::setInteractive(bool interactive)
     Q_D(QDeclarativeFlickable);
     if (interactive != d->interactive) {
         d->interactive = interactive;
-        if (!interactive && (d->flickingHorizontally || d->flickingVertically)) {
+        if (!interactive && (d->hData.flicking || d->vData.flicking)) {
             d->timeline.clear();
             d->vTime = d->timeline.time();
-            d->flickingHorizontally = false;
-            d->flickingVertically = false;
+            d->hData.flicking = false;
+            d->vData.flicking = false;
             emit flickingChanged();
             emit flickingHorizontallyChanged();
             emit flickingVerticallyChanged();
@@ -771,8 +769,8 @@ void QDeclarativeFlickablePrivate::handleMousePressEvent(QGraphicsSceneMouseEven
     pressPos = event->pos();
     hData.pressPos = hData.move.value();
     vData.pressPos = vData.move.value();
-    flickingHorizontally = false;
-    flickingVertically = false;
+    hData.flicking = false;
+    vData.flicking = false;
     QDeclarativeItemPrivate::start(pressTime);
     QDeclarativeItemPrivate::start(velocityTime);
 }
@@ -897,17 +895,13 @@ void QDeclarativeFlickablePrivate::handleMouseReleaseEvent(QGraphicsSceneMouseEv
         return;
 
     // if we drag then pause before release we should not cause a flick.
-    if (QDeclarativeItemPrivate::elapsed(lastPosTime) < 100) {
-        vData.updateVelocity();
-        hData.updateVelocity();
-    } else {
-        hData.velocity = 0.0;
-        vData.velocity = 0.0;
-    }
+    qint64 elapsed = QDeclarativeItemPrivate::elapsed(lastPosTime);
 
+    vData.updateVelocity();
+    hData.updateVelocity();
     vTime = timeline.time();
 
-    qreal velocity = vData.velocity;
+    qreal velocity = elapsed < 100 ? vData.velocity : 0;
     if (vData.atBeginning || vData.atEnd)
         velocity /= 2;
     if (q->yflick() && qAbs(velocity) > MinimumFlickVelocity && qAbs(event->pos().y() - pressPos.y()) > FlickThreshold) {
@@ -918,7 +912,7 @@ void QDeclarativeFlickablePrivate::handleMouseReleaseEvent(QGraphicsSceneMouseEv
         fixupY();
     }
 
-    velocity = hData.velocity;
+    velocity = elapsed < 100 ? hData.velocity : 0;
     if (hData.atBeginning || hData.atEnd)
         velocity /= 2;
     if (q->xflick() && qAbs(velocity) > MinimumFlickVelocity && qAbs(event->pos().x() - pressPos.x()) > FlickThreshold) {
@@ -984,9 +978,9 @@ void QDeclarativeFlickable::wheelEvent(QGraphicsSceneWheelEvent *event)
             valid = true;
         }
         if (valid) {
-            d->flickingVertically = false;
+            d->vData.flicking = false;
             d->flickY(d->vData.velocity);
-            if (d->flickingVertically) {
+            if (d->vData.flicking) {
                 d->vMoved = true;
                 movementStarting();
             }
@@ -1002,9 +996,9 @@ void QDeclarativeFlickable::wheelEvent(QGraphicsSceneWheelEvent *event)
             valid = true;
         }
         if (valid) {
-            d->flickingHorizontally = false;
+            d->hData.flicking = false;
             d->flickX(d->hData.velocity);
-            if (d->flickingHorizontally) {
+            if (d->hData.flicking) {
                 d->hMoved = true;
                 movementStarting();
             }
@@ -1153,7 +1147,7 @@ void QDeclarativeFlickable::viewportMoved()
         }
     }
 
-    if (!d->vData.inOvershoot && !d->vData.fixingUp && d->flickingVertically
+    if (!d->vData.inOvershoot && !d->vData.fixingUp && d->vData.flicking
             && (d->vData.move.value() > minYExtent() || d->vData.move.value() < maxYExtent())
             && qAbs(d->vData.smoothVelocity.value()) > 100) {
         // Increase deceleration if we've passed a bound
@@ -1163,7 +1157,7 @@ void QDeclarativeFlickable::viewportMoved()
         d->timeline.accel(d->vData.move, -d->vData.smoothVelocity.value(), d->deceleration*QML_FLICK_OVERSHOOTFRICTION, maxDistance);
         d->timeline.callback(QDeclarativeTimeLineCallback(&d->vData.move, d->fixupY_callback, d));
     }
-    if (!d->hData.inOvershoot && !d->hData.fixingUp && d->flickingHorizontally
+    if (!d->hData.inOvershoot && !d->hData.fixingUp && d->hData.flicking
             && (d->hData.move.value() > minXExtent() || d->hData.move.value() < maxXExtent())
             && qAbs(d->hData.smoothVelocity.value()) > 100) {
         // Increase deceleration if we've passed a bound
@@ -1195,7 +1189,7 @@ void QDeclarativeFlickable::geometryChanged(const QRectF &newGeometry,
             emit contentWidthChanged();
         }
         // Make sure that we're entirely in view.
-        if (!d->pressed && !d->movingHorizontally && !d->movingVertically) {
+        if (!d->pressed && !d->hData.moving && !d->vData.moving) {
             d->fixupMode = QDeclarativeFlickablePrivate::Immediate;
             d->fixupX();
         }
@@ -1208,7 +1202,7 @@ void QDeclarativeFlickable::geometryChanged(const QRectF &newGeometry,
             emit contentHeightChanged();
         }
         // Make sure that we're entirely in view.
-        if (!d->pressed && !d->movingHorizontally && !d->movingVertically) {
+        if (!d->pressed && !d->hData.moving && !d->vData.moving) {
             d->fixupMode = QDeclarativeFlickablePrivate::Immediate;
             d->fixupY();
         }
@@ -1384,7 +1378,7 @@ void QDeclarativeFlickable::setContentWidth(qreal w)
     else
         d->contentItem->setWidth(w);
     // Make sure that we're entirely in view.
-    if (!d->pressed && !d->movingHorizontally && !d->movingVertically) {
+    if (!d->pressed && !d->hData.moving && !d->vData.moving) {
         d->fixupMode = QDeclarativeFlickablePrivate::Immediate;
         d->fixupX();
     } else if (!d->pressed && d->hData.fixingUp) {
@@ -1412,7 +1406,7 @@ void QDeclarativeFlickable::setContentHeight(qreal h)
     else
         d->contentItem->setHeight(h);
     // Make sure that we're entirely in view.
-    if (!d->pressed && !d->movingHorizontally && !d->movingVertically) {
+    if (!d->pressed && !d->hData.moving && !d->vData.moving) {
         d->fixupMode = QDeclarativeFlickablePrivate::Immediate;
         d->fixupY();
     } else if (!d->pressed && d->vData.fixingUp) {
@@ -1668,7 +1662,7 @@ void QDeclarativeFlickable::setFlickDeceleration(qreal deceleration)
 bool QDeclarativeFlickable::isFlicking() const
 {
     Q_D(const QDeclarativeFlickable);
-    return d->flickingHorizontally ||  d->flickingVertically;
+    return d->hData.flicking ||  d->vData.flicking;
 }
 
 /*!
@@ -1682,13 +1676,13 @@ bool QDeclarativeFlickable::isFlicking() const
 bool QDeclarativeFlickable::isFlickingHorizontally() const
 {
     Q_D(const QDeclarativeFlickable);
-    return d->flickingHorizontally;
+    return d->hData.flicking;
 }
 
 bool QDeclarativeFlickable::isFlickingVertically() const
 {
     Q_D(const QDeclarativeFlickable);
-    return d->flickingVertically;
+    return d->vData.flicking;
 }
 
 /*!
@@ -1724,7 +1718,7 @@ void QDeclarativeFlickable::setPressDelay(int delay)
 bool QDeclarativeFlickable::isMoving() const
 {
     Q_D(const QDeclarativeFlickable);
-    return d->movingHorizontally || d->movingVertically;
+    return d->hData.moving || d->vData.moving;
 }
 
 /*!
@@ -1739,30 +1733,30 @@ bool QDeclarativeFlickable::isMoving() const
 bool QDeclarativeFlickable::isMovingHorizontally() const
 {
     Q_D(const QDeclarativeFlickable);
-    return d->movingHorizontally;
+    return d->hData.moving;
 }
 
 bool QDeclarativeFlickable::isMovingVertically() const
 {
     Q_D(const QDeclarativeFlickable);
-    return d->movingVertically;
+    return d->vData.moving;
 }
 
 void QDeclarativeFlickable::movementStarting()
 {
     Q_D(QDeclarativeFlickable);
-    if (d->hMoved && !d->movingHorizontally) {
-        d->movingHorizontally = true;
+    if (d->hMoved && !d->hData.moving) {
+        d->hData.moving = true;
         emit movingChanged();
         emit movingHorizontallyChanged();
-        if (!d->movingVertically)
+        if (!d->vData.moving)
             emit movementStarted();
     }
-    else if (d->vMoved && !d->movingVertically) {
-        d->movingVertically = true;
+    else if (d->vMoved && !d->vData.moving) {
+        d->vData.moving = true;
         emit movingChanged();
         emit movingVerticallyChanged();
-        if (!d->movingHorizontally)
+        if (!d->hData.moving)
             emit movementStarted();
     }
 }
@@ -1779,20 +1773,20 @@ void QDeclarativeFlickable::movementEnding()
 void QDeclarativeFlickable::movementXEnding()
 {
     Q_D(QDeclarativeFlickable);
-    if (d->flickingHorizontally) {
-        d->flickingHorizontally = false;
+    if (d->hData.flicking) {
+        d->hData.flicking = false;
         emit flickingChanged();
         emit flickingHorizontallyChanged();
-        if (!d->flickingVertically)
+        if (!d->vData.flicking)
            emit flickEnded();
     }
     if (!d->pressed && !d->stealMouse) {
-        if (d->movingHorizontally) {
-            d->movingHorizontally = false;
+        if (d->hData.moving) {
+            d->hData.moving = false;
             d->hMoved = false;
             emit movingChanged();
             emit movingHorizontallyChanged();
-            if (!d->movingVertically)
+            if (!d->vData.moving)
                 emit movementEnded();
         }
     }
@@ -1802,20 +1796,20 @@ void QDeclarativeFlickable::movementXEnding()
 void QDeclarativeFlickable::movementYEnding()
 {
     Q_D(QDeclarativeFlickable);
-    if (d->flickingVertically) {
-        d->flickingVertically = false;
+    if (d->vData.flicking) {
+        d->vData.flicking = false;
         emit flickingChanged();
         emit flickingVerticallyChanged();
-        if (!d->flickingHorizontally)
+        if (!d->hData.flicking)
            emit flickEnded();
     }
     if (!d->pressed && !d->stealMouse) {
-        if (d->movingVertically) {
-            d->movingVertically = false;
+        if (d->vData.moving) {
+            d->vData.moving = false;
             d->vMoved = false;
             emit movingChanged();
             emit movingVerticallyChanged();
-            if (!d->movingHorizontally)
+            if (!d->hData.moving)
                 emit movementEnded();
         }
     }
diff --git a/src/declarative/graphicsitems/qdeclarativeflickable_p_p.h b/src/declarative/graphicsitems/qdeclarativeflickable_p_p.h
index 1c749cd..d73a907 100644
--- a/src/declarative/graphicsitems/qdeclarativeflickable_p_p.h
+++ b/src/declarative/graphicsitems/qdeclarativeflickable_p_p.h
@@ -63,6 +63,7 @@
 #include <qdeclarativeanimation_p_p.h>
 
 #include <qdatetime.h>
+#include "qplatformdefs.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -98,7 +99,7 @@ public:
     struct AxisData {
         AxisData(QDeclarativeFlickablePrivate *fp, void (QDeclarativeFlickablePrivate::*func)(qreal))
             : move(fp, func), viewSize(-1), smoothVelocity(fp), atEnd(false), atBeginning(true)
-            , fixingUp(false), inOvershoot(false)
+            , fixingUp(false), inOvershoot(false), moving(false), flicking(false)
         {}
 
         void reset() {
@@ -125,6 +126,8 @@ public:
         bool atBeginning : 1;
         bool fixingUp : 1;
         bool inOvershoot : 1;
+        bool moving : 1;
+        bool flicking : 1;
     };
 
     void flickX(qreal velocity);
@@ -156,12 +159,8 @@ public:
     AxisData vData;
 
     QDeclarativeTimeLine timeline;
-    bool flickingHorizontally : 1;
-    bool flickingVertically : 1;
     bool hMoved : 1;
     bool vMoved : 1;
-    bool movingHorizontally : 1;
-    bool movingVertically : 1;
     bool stealMouse : 1;
     bool pressed : 1;
     bool interactive : 1;
diff --git a/src/declarative/graphicsitems/qdeclarativegridview.cpp b/src/declarative/graphicsitems/qdeclarativegridview.cpp
index afc3eac..59e4cbb 100644
--- a/src/declarative/graphicsitems/qdeclarativegridview.cpp
+++ b/src/declarative/graphicsitems/qdeclarativegridview.cpp
@@ -52,9 +52,13 @@
 
 #include <qmath.h>
 #include <math.h>
+#include "qplatformdefs.h"
 
 QT_BEGIN_NAMESPACE
 
+#ifndef QML_FLICK_SNAPONETHRESHOLD
+#define QML_FLICK_SNAPONETHRESHOLD 30
+#endif
 
 //----------------------------------------------------------------------------
 
@@ -344,9 +348,12 @@ public:
         Q_Q(const QDeclarativeGridView);
         qreal snapPos = 0;
         if (!visibleItems.isEmpty()) {
+            qreal highlightStart = isRightToLeftTopToBottom() && highlightRangeStartValid ? size()-highlightRangeEnd : highlightRangeStart;
+            pos += highlightStart;
             pos += rowSize()/2;
             snapPos = visibleItems.first()->rowPos() - visibleIndex / columns * rowSize();
             snapPos = pos - fmodf(pos - snapPos, qreal(rowSize()));
+            snapPos -= highlightStart;
             qreal maxExtent;
             qreal minExtent;
             if (isRightToLeftTopToBottom()) {
@@ -872,7 +879,7 @@ void QDeclarativeGridViewPrivate::updateHighlight()
 {
     if ((!currentItem && highlight) || (currentItem && !highlight))
         createHighlight();
-    if (currentItem && autoHighlight && highlight && !movingHorizontally && !movingVertically) {
+    if (currentItem && autoHighlight && highlight && !hData.moving && !vData.moving) {
         // auto-update highlight
         highlightXAnimator->to = currentItem->item->x();
         highlightYAnimator->to = currentItem->item->y();
@@ -1059,6 +1066,18 @@ void QDeclarativeGridViewPrivate::fixup(AxisData &data, qreal minExtent, qreal m
 
     if (snapMode != QDeclarativeGridView::NoSnap) {
         qreal tempPosition = isRightToLeftTopToBottom() ? -position()-size() : position();
+        if (snapMode == QDeclarativeGridView::SnapOneRow && moveReason == Mouse) {
+            // if we've been dragged < rowSize()/2 then bias towards the next row
+            qreal dist = data.move.value() - (data.pressPos - data.dragStartOffset);
+            qreal bias = 0;
+            if (data.velocity > 0 && dist > QML_FLICK_SNAPONETHRESHOLD && dist < rowSize()/2)
+                bias = rowSize()/2;
+            else if (data.velocity < 0 && dist < -QML_FLICK_SNAPONETHRESHOLD && dist > -rowSize()/2)
+                bias = -rowSize()/2;
+            if (isRightToLeftTopToBottom())
+                bias = -bias;
+            tempPosition -= bias;
+        }
         FxGridItem *topItem = snapItemAt(tempPosition+highlightStart);
         FxGridItem *bottomItem = snapItemAt(tempPosition+highlightEnd);
         qreal pos;
@@ -1080,25 +1099,13 @@ void QDeclarativeGridViewPrivate::fixup(AxisData &data, qreal minExtent, qreal m
             }
         } else if (bottomItem) {
             if (isRightToLeftTopToBottom())
-                pos = qMax(qMin(-bottomItem->rowPos() + highlightStart - size(), -maxExtent), -minExtent);
+                pos = qMax(qMin(-bottomItem->rowPos() + highlightEnd - size(), -maxExtent), -minExtent);
             else
-                pos = qMax(qMin(bottomItem->rowPos() - highlightStart, -maxExtent), -minExtent);
+                pos = qMax(qMin(bottomItem->rowPos() - highlightEnd, -maxExtent), -minExtent);
         } else {
             QDeclarativeFlickablePrivate::fixup(data, minExtent, maxExtent);
             return;
         }
-        if (currentItem && haveHighlightRange && highlightRange == QDeclarativeGridView::StrictlyEnforceRange) {
-            updateHighlight();
-            qreal currPos = currentItem->rowPos();
-            if (isRightToLeftTopToBottom())
-                pos = -pos-size(); // Transform Pos if required
-            if (pos < currPos + rowSize() - highlightEnd)
-                pos = currPos + rowSize() - highlightEnd;
-            if (pos > currPos - highlightStart)
-                pos = currPos - highlightStart;
-            if (isRightToLeftTopToBottom())
-                pos = -pos-size(); // Untransform
-        }
         qreal dist = qAbs(data.move + pos);
         if (dist > 0) {
             timeline.reset(data.move);
@@ -1155,9 +1162,14 @@ void QDeclarativeGridViewPrivate::flick(AxisData &data, qreal minExtent, qreal m
     if (velocity > 0) {
         if (data.move.value() < minExtent) {
             if (snapMode == QDeclarativeGridView::SnapOneRow) {
-                if (FxGridItem *item = firstVisibleItem()) {
-                    maxDistance = qAbs(item->rowPos() + dataValue);
-                }
+                // if we've been dragged < averageSize/2 then bias towards the next item
+                qreal dist = data.move.value() - (data.pressPos - data.dragStartOffset);
+                qreal bias = dist < rowSize()/2 ? rowSize()/2 : 0;
+                if (isRightToLeftTopToBottom())
+                    bias = -bias;
+                data.flickTarget = -snapPosAt(-dataValue - bias);
+                maxDistance = qAbs(data.flickTarget - data.move.value());
+                velocity = maxVelocity;
             } else {
                 maxDistance = qAbs(minExtent - data.move.value());
             }
@@ -1167,8 +1179,14 @@ void QDeclarativeGridViewPrivate::flick(AxisData &data, qreal minExtent, qreal m
     } else {
         if (data.move.value() > maxExtent) {
             if (snapMode == QDeclarativeGridView::SnapOneRow) {
-                qreal pos = snapPosAt(-dataValue) + (isRightToLeftTopToBottom() ? 0 : rowSize());
-                maxDistance = qAbs(pos + dataValue);
+                // if we've been dragged < averageSize/2 then bias towards the next item
+                qreal dist = data.move.value() - (data.pressPos - data.dragStartOffset);
+                qreal bias = -dist < rowSize()/2 ? rowSize()/2 : 0;
+                if (isRightToLeftTopToBottom())
+                    bias = -bias;
+                data.flickTarget = -snapPosAt(-dataValue + bias);
+                maxDistance = qAbs(data.flickTarget - data.move.value());
+                velocity = -maxVelocity;
             } else {
                 maxDistance = qAbs(maxExtent - data.move.value());
             }
@@ -1178,7 +1196,6 @@ void QDeclarativeGridViewPrivate::flick(AxisData &data, qreal minExtent, qreal m
     }
 
     bool overShoot = boundsBehavior == QDeclarativeFlickable::DragAndOvershootBounds;
-    qreal highlightStart = isRightToLeftTopToBottom() && highlightRangeStartValid ? size()-highlightRangeEnd : highlightRangeStart;
 
     if (maxDistance > 0 || overShoot) {
         // This mode requires the grid to stop exactly on a row boundary.
@@ -1198,9 +1215,20 @@ void QDeclarativeGridViewPrivate::flick(AxisData &data, qreal minExtent, qreal m
             dist = qMin(dist, maxDistance);
             if (v > 0)
                 dist = -dist;
-            qreal distTemp = isRightToLeftTopToBottom() ? -dist : dist;
-            data.flickTarget = -snapPosAt(-(dataValue - highlightStart) + distTemp) + highlightStart;
+            if (snapMode != QDeclarativeGridView::SnapOneRow) {
+                qreal distTemp = isRightToLeftTopToBottom() ? -dist : dist;
+                data.flickTarget = -snapPosAt(-dataValue + distTemp);
+            }
             data.flickTarget = isRightToLeftTopToBottom() ? -data.flickTarget+size() : data.flickTarget;
+            if (overShoot) {
+                if (data.flickTarget >= minExtent) {
+                    overshootDist = overShootDistance(vSize);
+                    data.flickTarget += overshootDist;
+                } else if (data.flickTarget <= maxExtent) {
+                    overshootDist = overShootDistance(vSize);
+                    data.flickTarget -= overshootDist;
+                }
+            }
             qreal adjDist = -data.flickTarget + data.move.value();
             if (qAbs(adjDist) > qAbs(dist)) {
                 // Prevent painfully slow flicking - adjust velocity to suit flickDeceleration
@@ -1221,14 +1249,14 @@ void QDeclarativeGridViewPrivate::flick(AxisData &data, qreal minExtent, qreal m
         timeline.reset(data.move);
         timeline.accel(data.move, v, accel, maxDistance + overshootDist);
         timeline.callback(QDeclarativeTimeLineCallback(&data.move, fixupCallback, this));
-        if (!flickingHorizontally && q->xflick()) {
-            flickingHorizontally = true;
+        if (!hData.flicking && q->xflick()) {
+            hData.flicking = true;
             emit q->flickingChanged();
             emit q->flickingHorizontallyChanged();
             emit q->flickStarted();
         }
-        if (!flickingVertically && q->yflick()) {
-            flickingVertically = true;
+        if (!vData.flicking && q->yflick()) {
+            vData.flicking = true;
             emit q->flickingChanged();
             emit q->flickingVerticallyChanged();
             emit q->flickStarted();
@@ -1552,6 +1580,8 @@ void QDeclarativeGridView::setCurrentIndex(int index)
     if (index == d->currentIndex)
         return;
     if (isComponentComplete() && d->isValid()) {
+        if (d->layoutScheduled)
+            d->layout();
         d->moveReason = QDeclarativeGridViewPrivate::SetIndex;
         d->updateCurrent(index);
     } else {
@@ -2096,7 +2126,8 @@ bool QDeclarativeGridView::event(QEvent *event)
 {
     Q_D(QDeclarativeGridView);
     if (event->type() == QEvent::User) {
-        d->layout();
+        if (d->layoutScheduled)
+            d->layout();
         return true;
     }
 
@@ -2110,7 +2141,7 @@ void QDeclarativeGridView::viewportMoved()
     if (!d->itemCount)
         return;
     d->lazyRelease = true;
-    if (d->flickingHorizontally || d->flickingVertically) {
+    if (d->hData.flicking || d->vData.flicking) {
         if (yflick()) {
             if (d->vData.velocity > 0)
                 d->bufferMode = QDeclarativeGridViewPrivate::BufferBefore;
@@ -2126,7 +2157,7 @@ void QDeclarativeGridView::viewportMoved()
         }
     }
     refill();
-    if (d->flickingHorizontally || d->flickingVertically || d->movingHorizontally || d->movingVertically)
+    if (d->hData.flicking || d->vData.flicking || d->hData.moving || d->vData.moving)
         d->moveReason = QDeclarativeGridViewPrivate::Mouse;
     if (d->moveReason != QDeclarativeGridViewPrivate::SetIndex) {
         if (d->haveHighlightRange && d->highlightRange == StrictlyEnforceRange && d->highlight) {
@@ -2871,7 +2902,6 @@ void QDeclarativeGridView::itemsRemoved(int modelIndex, int count)
     d->itemCount -= count;
     bool currentRemoved = d->currentIndex >= modelIndex && d->currentIndex < modelIndex + count;
     bool removedVisible = false;
-
     // Remove the items from the visible list, skipping anything already marked for removal
     QList<FxGridItem*>::Iterator it = d->visibleItems.begin();
     while (it != d->visibleItems.end()) {
@@ -2905,6 +2935,11 @@ void QDeclarativeGridView::itemsRemoved(int modelIndex, int count)
         }
     }
 
+    // If we removed items before visible items a layout may be
+    // required to ensure item 0 is in the first column.
+    if (!removedVisible && modelIndex < d->visibleIndex)
+        d->scheduleLayout();
+
     // fix current
     if (d->currentIndex >= modelIndex + count) {
         d->currentIndex -= count;
diff --git a/src/declarative/graphicsitems/qdeclarativelistview.cpp b/src/declarative/graphicsitems/qdeclarativelistview.cpp
index 8695bc6..57b7dea 100644
--- a/src/declarative/graphicsitems/qdeclarativelistview.cpp
+++ b/src/declarative/graphicsitems/qdeclarativelistview.cpp
@@ -53,9 +53,14 @@
 #include <qlistmodelinterface_p.h>
 #include <qmath.h>
 #include <QKeyEvent>
+#include "qplatformdefs.h"
 
 QT_BEGIN_NAMESPACE
 
+#ifndef QML_FLICK_SNAPONETHRESHOLD
+#define QML_FLICK_SNAPONETHRESHOLD 30
+#endif
+
 void QDeclarativeViewSection::setProperty(const QString &property)
 {
     if (property != m_property) {
@@ -234,21 +239,6 @@ public:
         return visibleItems.count() ? visibleItems.first() : 0;
     }
 
-    FxListItem *nextVisibleItem() const {
-        const qreal pos = isRightToLeft() ? -position()-size() : position();
-        bool foundFirst = false;
-        for (int i = 0; i < visibleItems.count(); ++i) {
-            FxListItem *item = visibleItems.at(i);
-            if (item->index != -1) {
-                if (foundFirst)
-                    return item;
-                else if (item->position() < pos && item->endPosition() > pos)
-                    foundFirst = true;
-            }
-        }
-        return 0;
-    }
-
     // Returns the item before modelIndex, if created.
     // May return an item marked for removal.
     FxListItem *itemBefore(int modelIndex) const {
@@ -1007,7 +997,7 @@ void QDeclarativeListViewPrivate::updateHighlight()
 {
     if ((!currentItem && highlight) || (currentItem && !highlight))
         createHighlight();
-    if (currentItem && autoHighlight && highlight && !movingHorizontally && !movingVertically) {
+    if (currentItem && autoHighlight && highlight && !hData.moving && !vData.moving) {
         // auto-update highlight
         highlightPosAnimator->to = isRightToLeft()
                 ? -currentItem->itemPosition()-currentItem->itemSize()
@@ -1318,29 +1308,20 @@ void QDeclarativeListViewPrivate::fixup(AxisData &data, qreal minExtent, qreal m
         highlightEnd = highlightRangeEnd;
     }
 
-    if (currentItem && haveHighlightRange && highlightRange == QDeclarativeListView::StrictlyEnforceRange
-            && moveReason != QDeclarativeListViewPrivate::SetIndex) {
-        updateHighlight();
-        qreal pos = currentItem->itemPosition();
-        if (viewPos < pos + currentItem->itemSize() - highlightEnd)
-            viewPos = pos + currentItem->itemSize() - highlightEnd;
-        if (viewPos > pos - highlightStart)
-            viewPos = pos - highlightStart;
-        if (isRightToLeft())
-            viewPos = -viewPos-size();
-
-        timeline.reset(data.move);
-        if (viewPos != position()) {
-            if (fixupMode != Immediate) {
-                timeline.move(data.move, -viewPos, QEasingCurve(QEasingCurve::InOutQuad), fixupDuration/2);
-                data.fixingUp = true;
-            } else {
-                timeline.set(data.move, -viewPos);
-            }
-        }
-        vTime = timeline.time();
-    } else if (snapMode != QDeclarativeListView::NoSnap && moveReason != QDeclarativeListViewPrivate::SetIndex) {
+    if (snapMode != QDeclarativeListView::NoSnap && moveReason != QDeclarativeListViewPrivate::SetIndex) {
         qreal tempPosition = isRightToLeft() ? -position()-size() : position();
+        if (snapMode == QDeclarativeListView::SnapOneItem && moveReason == Mouse) {
+            // if we've been dragged < averageSize/2 then bias towards the next item
+            qreal dist = data.move.value() - (data.pressPos - data.dragStartOffset);
+            qreal bias = 0;
+            if (data.velocity > 0 && dist > QML_FLICK_SNAPONETHRESHOLD && dist < averageSize/2)
+                bias = averageSize/2;
+            else if (data.velocity < 0 && dist < -QML_FLICK_SNAPONETHRESHOLD && dist > -averageSize/2)
+                bias = -averageSize/2;
+            if (isRightToLeft())
+                bias = -bias;
+            tempPosition -= bias;
+        }
         FxListItem *topItem = snapItemAt(tempPosition+highlightStart);
         FxListItem *bottomItem = snapItemAt(tempPosition+highlightEnd);
         qreal pos;
@@ -1356,9 +1337,9 @@ void QDeclarativeListViewPrivate::fixup(AxisData &data, qreal minExtent, qreal m
             }
         } else if (bottomItem && isInBounds) {
             if (isRightToLeft())
-                pos = qMax(qMin(-bottomItem->position() + highlightStart - size(), -maxExtent), -minExtent);
+                pos = qMax(qMin(-bottomItem->position() + highlightEnd - size(), -maxExtent), -minExtent);
             else
-                pos = qMax(qMin(bottomItem->position() - highlightStart, -maxExtent), -minExtent);
+                pos = qMax(qMin(bottomItem->position() - highlightEnd, -maxExtent), -minExtent);
         } else {
             QDeclarativeFlickablePrivate::fixup(data, minExtent, maxExtent);
             return;
@@ -1375,6 +1356,27 @@ void QDeclarativeListViewPrivate::fixup(AxisData &data, qreal minExtent, qreal m
             }
             vTime = timeline.time();
         }
+    } else if (currentItem && haveHighlightRange && highlightRange == QDeclarativeListView::StrictlyEnforceRange
+                && moveReason != QDeclarativeListViewPrivate::SetIndex) {
+        updateHighlight();
+        qreal pos = currentItem->itemPosition();
+        if (viewPos < pos + currentItem->itemSize() - highlightEnd)
+            viewPos = pos + currentItem->itemSize() - highlightEnd;
+        if (viewPos > pos - highlightStart)
+            viewPos = pos - highlightStart;
+        if (isRightToLeft())
+            viewPos = -viewPos-size();
+
+        timeline.reset(data.move);
+        if (viewPos != position()) {
+            if (fixupMode != Immediate) {
+                timeline.move(data.move, -viewPos, QEasingCurve(QEasingCurve::InOutQuad), fixupDuration/2);
+                data.fixingUp = true;
+            } else {
+                timeline.set(data.move, -viewPos);
+            }
+        }
+        vTime = timeline.time();
     } else {
         QDeclarativeFlickablePrivate::fixup(data, minExtent, maxExtent);
     }
@@ -1396,12 +1398,19 @@ void QDeclarativeListViewPrivate::flick(AxisData &data, qreal minExtent, qreal m
     }
     qreal maxDistance = 0;
     qreal dataValue = isRightToLeft() ? -data.move.value()+size() : data.move.value();
+    qreal highlightStart = isRightToLeft() && highlightRangeStartValid ? size()-highlightRangeEnd : highlightRangeStart;
     // -ve velocity means list is moving up/left
     if (velocity > 0) {
         if (data.move.value() < minExtent) {
-            if (snapMode == QDeclarativeListView::SnapOneItem) {
-                if (FxListItem *item = isRightToLeft() ? nextVisibleItem() : firstVisibleItem())
-                    maxDistance = qAbs(item->position() + dataValue);
+            if (snapMode == QDeclarativeListView::SnapOneItem && !hData.flicking && !vData.flicking) {
+                // if we've been dragged < averageSize/2 then bias towards the next item
+                qreal dist = data.move.value() - (data.pressPos - data.dragStartOffset);
+                qreal bias = dist < averageSize/2 ? averageSize/2 : 0;
+                if (isRightToLeft())
+                    bias = -bias;
+                data.flickTarget = -snapPosAt(-(dataValue - highlightStart) - bias) + highlightStart;
+                maxDistance = qAbs(data.flickTarget - data.move.value());
+                velocity = maxVelocity;
             } else {
                 maxDistance = qAbs(minExtent - data.move.value());
             }
@@ -1410,9 +1419,15 @@ void QDeclarativeListViewPrivate::flick(AxisData &data, qreal minExtent, qreal m
             data.flickTarget = minExtent;
     } else {
         if (data.move.value() > maxExtent) {
-            if (snapMode == QDeclarativeListView::SnapOneItem) {
-                if (FxListItem *item = isRightToLeft() ? firstVisibleItem() : nextVisibleItem())
-                    maxDistance = qAbs(item->position() + dataValue);
+            if (snapMode == QDeclarativeListView::SnapOneItem && !hData.flicking && !vData.flicking) {
+                // if we've been dragged < averageSize/2 then bias towards the next item
+                qreal dist = data.move.value() - (data.pressPos - data.dragStartOffset);
+                qreal bias = -dist < averageSize/2 ? averageSize/2 : 0;
+                if (isRightToLeft())
+                    bias = -bias;
+                data.flickTarget = -snapPosAt(-(dataValue - highlightStart) + bias) + highlightStart;
+                maxDistance = qAbs(data.flickTarget - data.move.value());
+                velocity = -maxVelocity;
             } else {
                 maxDistance = qAbs(maxExtent - data.move.value());
             }
@@ -1422,7 +1437,6 @@ void QDeclarativeListViewPrivate::flick(AxisData &data, qreal minExtent, qreal m
     }
 
     bool overShoot = boundsBehavior == QDeclarativeFlickable::DragAndOvershootBounds;
-    qreal highlightStart = isRightToLeft() && highlightRangeStartValid ? size()-highlightRangeEnd : highlightRangeStart;
 
     if (maxDistance > 0 || overShoot) {
         // These modes require the list to stop exactly on an item boundary.
@@ -1436,7 +1450,7 @@ void QDeclarativeListViewPrivate::flick(AxisData &data, qreal minExtent, qreal m
             else
                 v = maxVelocity;
         }
-        if (!flickingHorizontally && !flickingVertically) {
+        if (!hData.flicking && !vData.flicking) {
             // the initial flick - estimate boundary
             qreal accel = deceleration;
             qreal v2 = v * v;
@@ -1448,8 +1462,10 @@ void QDeclarativeListViewPrivate::flick(AxisData &data, qreal minExtent, qreal m
             if (v > 0)
                 dist = -dist;
             if ((maxDistance > 0.0 && v2 / (2.0f * maxDistance) < accel) || snapMode == QDeclarativeListView::SnapOneItem) {
-                qreal distTemp = isRightToLeft() ? -dist : dist;
-                data.flickTarget = -snapPosAt(-(dataValue - highlightStart) + distTemp) + highlightStart;
+                if (snapMode != QDeclarativeListView::SnapOneItem) {
+                    qreal distTemp = isRightToLeft() ? -dist : dist;
+                    data.flickTarget = -snapPosAt(-(dataValue - highlightStart) + distTemp) + highlightStart;
+                }
                 data.flickTarget = isRightToLeft() ? -data.flickTarget+size() : data.flickTarget;
                 if (overShoot) {
                     if (data.flickTarget >= minExtent) {
@@ -1487,14 +1503,14 @@ void QDeclarativeListViewPrivate::flick(AxisData &data, qreal minExtent, qreal m
             timeline.reset(data.move);
             timeline.accel(data.move, v, accel, maxDistance + overshootDist);
             timeline.callback(QDeclarativeTimeLineCallback(&data.move, fixupCallback, this));
-            if (!flickingHorizontally && q->xflick()) {
-                flickingHorizontally = true;
+            if (!hData.flicking && q->xflick()) {
+                hData.flicking = true;
                 emit q->flickingChanged();
                 emit q->flickingHorizontallyChanged();
                 emit q->flickStarted();
             }
-            if (!flickingVertically && q->yflick()) {
-                flickingVertically = true;
+            if (!vData.flicking && q->yflick()) {
+                vData.flicking = true;
                 emit q->flickingChanged();
                 emit q->flickingVerticallyChanged();
                 emit q->flickStarted();
@@ -1870,6 +1886,8 @@ void QDeclarativeListView::setCurrentIndex(int index)
     if (index == d->currentIndex)
         return;
     if (isComponentComplete() && d->isValid()) {
+        if (d->layoutScheduled)
+            d->layout();
         d->moveReason = QDeclarativeListViewPrivate::SetIndex;
         d->updateCurrent(index);
     } else if (d->currentIndex != index) {
@@ -2555,7 +2573,8 @@ bool QDeclarativeListView::event(QEvent *event)
 {
     Q_D(QDeclarativeListView);
     if (event->type() == QEvent::User) {
-        d->layout();
+        if (d->layoutScheduled)
+            d->layout();
         return true;
     }
 
@@ -2574,7 +2593,7 @@ void QDeclarativeListView::viewportMoved()
     d->inViewportMoved = true;
     d->lazyRelease = true;
     refill();
-    if (d->flickingHorizontally || d->flickingVertically || d->movingHorizontally || d->movingVertically)
+    if (d->hData.flicking || d->vData.flicking || d->hData.moving || d->vData.moving)
         d->moveReason = QDeclarativeListViewPrivate::Mouse;
     if (d->moveReason != QDeclarativeListViewPrivate::SetIndex) {
         if (d->haveHighlightRange && d->highlightRange == StrictlyEnforceRange && d->highlight) {
@@ -2608,7 +2627,7 @@ void QDeclarativeListView::viewportMoved()
         }
     }
 
-    if ((d->flickingHorizontally || d->flickingVertically) && d->correctFlick && !d->inFlickCorrection) {
+    if ((d->hData.flicking || d->vData.flicking) && d->correctFlick && !d->inFlickCorrection) {
         d->inFlickCorrection = true;
         // Near an end and it seems that the extent has changed?
         // Recalculate the flick so that we don't end up in an odd position.