Add support for external drag and drop in Quick items.

Add dragType enums with values of None, Automatic, Internal (default).
Setting to Automatic allows startDrag to be called automatically.
Setting to Internal (default) retains old behavior.

Add mimeData to Drag item to enable external drags.

Call startDrag to start drag manually or change from internal drag to
external drag. Added events dragStarted and dragFinished that get
invoked from startDrag.

Mime data must be specified in the mimeData property as
mime-type / data pairs.

Moved QQuickDrag from qquickmousearea* files to qquickdrag* files to
reduce header interdependencies that caused linking errors in other
modules and also to improve code organization.

Allow DropArea to receive and process external data.

Introduced new variable containsDrag to QQuickDropAreaPrivate. This
replaces mimeData which was previously being used to determine if a
drop operation was currently occurring. The problem was that mimeData
was being externally destructed.

Also introduced accessor methods for getting color, html, image, text,
and urls out of the drop. This facilitates dropping of external data of
those types onto a DropArea.

Added example quick/externaldraganddrop.

Task-number: QTBUG-27498
Change-Id: I1420df7c161ea3399e49a23305273e106baa246f
Reviewed-by: Alan Alpert (Personal) <416365416c@gmail.com>

1 files changed, 190 insertions, 33 deletions

diff --git a/src/quick/items/qquickdroparea.cpp b/src/quick/items/qquickdroparea.cpp
index f453c42e5b..09dc7eeebb 100644
--- a/src/quick/items/qquickdroparea.cpp
+++ b/src/quick/items/qquickdroparea.cpp
@@ -77,11 +77,12 @@ public:
     QPointF dragPosition;
     QQuickDropAreaDrag *drag;
     QPointer<QObject> source;
-    QPointer<QMimeData> mimeData;
+    bool containsDrag;
 };
 
 QQuickDropAreaPrivate::QQuickDropAreaPrivate()
     : drag(0)
+    , containsDrag(false)
 {
 }
 
@@ -133,7 +134,7 @@ QQuickDropArea::~QQuickDropArea()
 bool QQuickDropArea::containsDrag() const
 {
     Q_D(const QQuickDropArea);
-    return d->mimeData;
+    return d->containsDrag;
 }
 
 /*!
@@ -217,7 +218,7 @@ qreal QQuickDropAreaDrag::y() const
 void QQuickDropArea::dragMoveEvent(QDragMoveEvent *event)
 {
     Q_D(QQuickDropArea);
-    if (!d->mimeData)
+    if (!d->containsDrag)
         return;
 
     d->dragPosition = event->pos();
@@ -259,28 +260,27 @@ void QQuickDropArea::dragEnterEvent(QDragEnterEvent *event)
 {
     Q_D(QQuickDropArea);
     const QMimeData *mimeData = event->mimeData();
-    if (!d->effectiveEnable || d->mimeData || !mimeData || !d->hasMatchingKey(d->getKeys(mimeData)))
+    if (!d->effectiveEnable || d->containsDrag || !mimeData || !d->hasMatchingKey(d->getKeys(mimeData)))
         return;
 
     d->dragPosition = event->pos();
 
     event->accept();
+
     QQuickDropEvent dragTargetEvent(d, event);
     emit entered(&dragTargetEvent);
 
-    if (event->isAccepted()) {
-        d->mimeData = const_cast<QMimeData *>(mimeData);
-        if (QQuickDragMimeData *dragMime = qobject_cast<QQuickDragMimeData *>(d->mimeData))
-            d->source = dragMime->source();
-        else
-            d->source = event->source();
-        d->dragPosition = event->pos();
-        if (d->drag) {
-            emit d->drag->positionChanged();
-            emit d->drag->sourceChanged();
-        }
-        emit containsDragChanged();
+    d->containsDrag = true;
+    if (QQuickDragMimeData *dragMime = qobject_cast<QQuickDragMimeData *>(const_cast<QMimeData *>(mimeData)))
+        d->source = dragMime->source();
+    else
+        d->source = event->source();
+    d->dragPosition = event->pos();
+    if (d->drag) {
+        emit d->drag->positionChanged();
+        emit d->drag->sourceChanged();
     }
+    emit containsDragChanged();
 }
 
 /*!
@@ -292,12 +292,12 @@ void QQuickDropArea::dragEnterEvent(QDragEnterEvent *event)
 void QQuickDropArea::dragLeaveEvent(QDragLeaveEvent *)
 {
     Q_D(QQuickDropArea);
-    if (!d->mimeData)
+    if (!d->containsDrag)
         return;
 
     emit exited();
 
-    d->mimeData = 0;
+    d->containsDrag = false;
     d->source = 0;
     emit containsDragChanged();
     if (d->drag)
@@ -314,13 +314,13 @@ void QQuickDropArea::dragLeaveEvent(QDragLeaveEvent *)
 void QQuickDropArea::dropEvent(QDropEvent *event)
 {
     Q_D(QQuickDropArea);
-    if (!d->mimeData)
+    if (!d->containsDrag)
         return;
 
     QQuickDropEvent dragTargetEvent(d, event);
     emit dropped(&dragTargetEvent);
 
-    d->mimeData = 0;
+    d->containsDrag = false;
     d->source = 0;
     emit containsDragChanged();
     if (d->drag)
@@ -337,6 +337,16 @@ void QQuickDropArea::dropEvent(QDropEvent *event)
     The position of the drag event can be obtained from the \l x and \l y
     properties, and the \l keys property identifies the drag keys of the event
     \l source.
+
+    The existence of specific drag types can be determined using the \l hasColor,
+    \l hasHtml, \l hasText, and \l hasUrls properties.
+
+    The list of all supplied formats can be determined using the \l formats property.
+
+    Specific drag types can be obtained using the \l colorData, \l html, \l text,
+    and \l urls properties.
+
+    A string version of any available mimeType can be obtained using \l getDataAsString.
 */
 
 /*!
@@ -357,14 +367,6 @@ void QQuickDropArea::dropEvent(QDropEvent *event)
     This property holds the source of a drag event.
 */
 
-QObject *QQuickDropEvent::source()
-{
-    if (const QQuickDragMimeData *dragMime = qobject_cast<const QQuickDragMimeData *>(event->mimeData()))
-        return dragMime->source();
-    else
-        return event->source();
-}
-
 /*!
     \qmlproperty stringlist QtQuick2::DragEvent::keys
 
@@ -372,11 +374,6 @@ QObject *QQuickDropEvent::source()
     drag event.
 */
 
-QStringList QQuickDropEvent::keys() const
-{
-    return d->getKeys(event->mimeData());
-}
-
 /*!
     \qmlproperty enumeration QtQuick2::DragEvent::action
 
@@ -400,6 +397,14 @@ QStringList QQuickDropEvent::keys() const
 */
 
 /*!
+    \qmlproperty flags QtQuick2::DragEvent::proposedAction
+    \since QtQuick 2.2
+
+    This property holds the set of \l {action}{actions} proposed by the
+    drag source.
+*/
+
+/*!
     \qmlproperty bool QtQuick2::DragEvent::accepted
 
     This property holds whether the drag event was accepted by a handler.
@@ -416,6 +421,157 @@ QStringList QQuickDropEvent::keys() const
     If an \a action is specified it will overwrite the value of the \l action property.
 */
 
+/*!
+    \qmlmethod QtQuick2::DragEvent::acceptProposedAction()
+    \since QtQuick 2.2
+
+    Accepts the drag event with the \l proposedAction.
+*/
+
+/*!
+    \qmlproperty bool QtQuick2::DragEvent::hasColor
+    \since QtQuick 2.2
+
+    This property holds whether the drag event contains a color item.
+*/
+
+/*!
+    \qmlproperty bool QtQuick2::DragEvent::hasHtml
+    \since QtQuick 2.2
+
+    This property holds whether the drag event contains a html item.
+*/
+
+/*!
+    \qmlproperty bool QtQuick2::DragEvent::hasText
+    \since QtQuick 2.2
+
+    This property holds whether the drag event contains a text item.
+*/
+
+/*!
+    \qmlproperty bool QtQuick2::DragEvent::hasUrls
+    \since QtQuick 2.2
+
+    This property holds whether the drag event contains one or more url items.
+*/
+
+/*!
+    \qmlproperty color QtQuick2::DragEvent::colorData
+    \since QtQuick 2.2
+
+    This property holds color data, if any.
+*/
+
+/*!
+    \qmlproperty string QtQuick2::DragEvent::html
+    \since QtQuick 2.2
+
+    This property holds html data, if any.
+*/
+
+/*!
+    \qmlproperty string QtQuick2::DragEvent::text
+    \since QtQuick 2.2
+
+    This property holds text data, if any.
+*/
+
+/*!
+    \qmlproperty urllist QtQuick2::DragEvent::urls
+    \since QtQuick 2.2
+
+    This property holds a list of urls, if any.
+*/
+
+/*!
+    \qmlproperty stringlist QtQuick2::DragEvent::formats
+    \since QtQuick 2.2
+
+    This property holds a list of mime type formats contained in the drag data.
+*/
+
+/*!
+    \qmlmethod string QtQuick2::DragEvent::getDataAsString(string format)
+    \since QtQuick 2.2
+
+    Returns the data for the given \a format converted to a string. \a format should be one contained in the \l formats property.
+*/
+
+QObject *QQuickDropEvent::source()
+{
+    if (const QQuickDragMimeData *dragMime = qobject_cast<const QQuickDragMimeData *>(event->mimeData()))
+        return dragMime->source();
+    else
+        return event->source();
+}
+
+QStringList QQuickDropEvent::keys() const
+{
+    return d->getKeys(event->mimeData());
+}
+
+bool QQuickDropEvent::hasColor() const
+{
+    return event->mimeData()->hasColor();
+}
+
+bool QQuickDropEvent::hasHtml() const
+{
+    return event->mimeData()->hasHtml();
+}
+
+bool QQuickDropEvent::hasText() const
+{
+    return event->mimeData()->hasText();
+}
+
+bool QQuickDropEvent::hasUrls() const
+{
+    return event->mimeData()->hasUrls();
+}
+
+QVariant QQuickDropEvent::colorData() const
+{
+    return event->mimeData()->colorData();
+}
+
+QString QQuickDropEvent::html() const
+{
+    return event->mimeData()->html();
+}
+
+QString QQuickDropEvent::text() const
+{
+    return event->mimeData()->text();
+}
+
+QList<QUrl> QQuickDropEvent::urls() const
+{
+    return event->mimeData()->urls();
+}
+
+QStringList QQuickDropEvent::formats() const
+{
+    return event->mimeData()->formats();
+}
+
+void QQuickDropEvent::getDataAsString(QQmlV4Function *args)
+{
+    if (args->length() != 0) {
+        QV4::Value v = (*args)[0];
+        QString format = v.toQString();
+        QString rv = QString::fromUtf8(event->mimeData()->data(format));
+        QV4::ExecutionEngine *v4 = QV8Engine::getV4(args->engine());
+        args->setReturnValue(QV4::Value::fromString(v4, rv));
+    }
+}
+
+void QQuickDropEvent::acceptProposedAction(QQmlV4Function *)
+{
+    event->acceptProposedAction();
+}
+
 void QQuickDropEvent::accept(QQmlV4Function *args)
 {
     Qt::DropAction action = event->dropAction();
@@ -425,6 +581,7 @@ void QQuickDropEvent::accept(QQmlV4Function *args)
         if (v.isInt32())
             action = Qt::DropAction(v.integerValue());
     }
+
     // get action from arguments.
     event->setDropAction(action);
     event->accept();