Menu: Enable "click-select-release" behavior

Some limitations in MouseArea force us to abandon the "one mouse area
per menu item" implementation in favor of a menu-wide mouse area,
where we track the position changes to highlight the menu item under
the mouse cursor. This makes possible updating the highlighted menu
item while keeping the mouse pressed.

Also, we need to emit an extra mouse press event, from the menu popup
window, so that the menu mouse area will receive any mouse release
event the user may have triggered. This is because the initial mouse
press event popping up the menu was made in another window, and
MouseArea would only emit 'released' signals if the released button
was already pressed.

Change-Id: Id10dd61fcf9e38ef3d34a61b7172301802e9646c
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>

4 files changed, 56 insertions, 67 deletions

diff --git a/examples/gallery/main.qml b/examples/gallery/main.qml
index 450fe5a0..455ed1d4 100644
--- a/examples/gallery/main.qml
+++ b/examples/gallery/main.qml
@@ -141,7 +141,7 @@ ApplicationWindow {
             exclusiveGroup: textFormatGroup
         }
 
-        ContextMenu {
+        Menu {
             id: editmenu
             MenuItem { action: cutAction }
             MenuItem { action: copyAction }
diff --git a/src/controls/Menu.qml b/src/controls/Menu.qml
index 1d2ca474..270c7869 100644
--- a/src/controls/Menu.qml
+++ b/src/controls/Menu.qml
@@ -94,6 +94,8 @@ MenuPrivate {
     property var menuBar: null
     //! internal
     property int currentIndex: -1
+    //! internal
+    onMenuClosed: currentIndex = -1
 
     //! internal
     menuContentItem: Loader {
@@ -166,7 +168,7 @@ MenuPrivate {
         Keys.onRightPressed: {
             var item = itemsRepeater.itemAt(root.currentIndex)
             if (item && item.hasSubmenu) {
-                item.menuItem.showPopup(menuFrameLoader.subMenuXPos, 0, -1, item)
+                item.showSubMenu()
                 item.menuItem.currentIndex = 0
             }
         }
@@ -195,8 +197,28 @@ MenuPrivate {
             id: menuMouseArea
             anchors.fill: parent
             hoverEnabled: true
-
-            onExited: root.currentIndex = -1 // TODO Test for any submenu open
+            acceptedButtons: Qt.AllButtons
+
+            onPositionChanged: updateCurrentItem(mouse)
+            onReleased: menuFrameLoader.triggerAndDismiss()
+
+            property Item currentItem: null
+
+            function updateCurrentItem(mouse) {
+                var pos = mapToItem(column, mouse.x, mouse.y)
+                if (!currentItem || !currentItem.contains(Qt.point(pos.x - currentItem.x, pos.y - currentItem.y))) {
+                    if (currentItem && !pressed && currentItem.hasSubmenu)
+                        currentItem.closeSubMenu()
+                    currentItem = column.childAt(pos.x, pos.y)
+                    if (currentItem) {
+                        root.currentIndex = currentItem.menuItemIndex
+                        if (currentItem.hasSubmenu && !currentItem.menuItem.popupVisible)
+                            currentItem.showSubMenu()
+                    } else {
+                        root.currentIndex = -1
+                    }
+                }
+            }
 
             // Each menu item has its own mouse area, and for events to be
             // propagated to the menu mouse area, they need to be embedded.
@@ -211,63 +233,33 @@ MenuPrivate {
                         id: menuItemLoader
 
                         property var menuItem: modelData
-                        property int contentWidth: column.width
-                        property int contentHeight: column.height
                         property bool isSeparator: menuItem ? !menuItem.hasOwnProperty("text") : false
                         property bool hasSubmenu: menuItem ? !!menuItem["menuItems"] : false
                         property bool selected: !isSeparator && root.currentIndex === index
 
+                        property int menuItemIndex: index
+
                         sourceComponent: menuFrameLoader.menuItemStyle
                         enabled: !isSeparator && !!menuItem && menuItem.enabled
 
-                        MouseArea {
-                            id: itemMouseArea
-                            width: menuFrameLoader.width
-                            height: parent.height
-                            y: menuItemLoader.item ? menuItemLoader.item.y : 0 // Adjust mouse area for style offset
-                            hoverEnabled: true
-
-                            onClicked: {
-                                if (hasSubmenu)
-                                    menuItem.closeMenu()
-                                menuFrameLoader.triggerAndDismiss()
-                            }
-
-                            onEntered: {
-                                if (menuItemLoader.hasSubmenu && !menuItem.popupVisible)
-                                    openMenuTimer.start()
-                            }
-
-                            onExited: {
-                                if (!pressed && menuItemLoader.hasSubmenu)
-                                    closeMenuTimer.start()
-                            }
-
-                            onPositionChanged: root.currentIndex = index
-
-                            Connections {
-                                target: menuMouseArea
-                                onEntered: {
-                                    if (!itemMouseArea.containsMouse && menuItemLoader.hasSubmenu)
-                                        closeMenuTimer.start()
-                                }
-                            }
-                        }
+                        function showSubMenu() { openMenuTimer.start() }
 
                         Timer {
                             id: openMenuTimer
                             interval: 50
                             onTriggered: {
-                                if (itemMouseArea.containsMouse)
+                                if (root.currentIndex === menuItemIndex)
                                     menuItem.showPopup(menuFrameLoader.subMenuXPos, 0, -1, menuItemLoader)
                             }
                         }
 
+                        function closeSubMenu() { closeMenuTimer.start() }
+
                         Timer {
                             id: closeMenuTimer
                             interval: 1
                             onTriggered: {
-                                if (menuMouseArea.containsMouse && !itemMouseArea.pressed && !itemMouseArea.containsMouse)
+                                if (root.currentIndex !== menuItemIndex)
                                     menuItem.closeMenu()
                             }
                         }
diff --git a/src/controls/qtmenupopupwindow.cpp b/src/controls/qtmenupopupwindow.cpp
index 7825f3bf..8b3bed45 100644
--- a/src/controls/qtmenupopupwindow.cpp
+++ b/src/controls/qtmenupopupwindow.cpp
@@ -47,7 +47,7 @@
 QT_BEGIN_NAMESPACE
 
 QtMenuPopupWindow::QtMenuPopupWindow(QWindow *parent) :
-    QQuickWindow(parent), m_pressedInside(true), m_itemAt(0)
+    QQuickWindow(parent), m_mouseMoved(false), m_itemAt(0)
 {
     setFlags(Qt::Popup);
     setModality(Qt::WindowModal);
@@ -111,41 +111,39 @@ void QtMenuPopupWindow::updatePosition()
 void QtMenuPopupWindow::mouseMoveEvent(QMouseEvent *e)
 {
     QRect rect = QRect(QPoint(), size());
-    QWindow *parentMenuWindow = /*qobject_cast<QtMenuPopupWindow*>*/(transientParent());
-    if (parentMenuWindow && !rect.contains(e->pos())) {
-        forwardEventToTransientParent(e);
-    } else {
+    if (rect.contains(e->pos())) {
+        m_mouseMoved = true;
         QQuickWindow::mouseMoveEvent(e);
+    } else {
+        forwardEventToTransientParent(e);
     }
 }
 
-void QtMenuPopupWindow::mousePressEvent(QMouseEvent *e)
-{
-    QRect rect = QRect(QPoint(), size());
-    m_pressedInside = rect.contains(e->pos());
-    if (m_pressedInside)
-        QQuickWindow::mousePressEvent(e);
-}
-
 void QtMenuPopupWindow::mouseReleaseEvent(QMouseEvent *e)
 {
     QRect rect = QRect(QPoint(), size());
-    if (rect.contains(e->pos()))
-        QQuickWindow::mouseReleaseEvent(e);
-    else if (!m_pressedInside)
-        dismissMenu();
-    else
+    if (rect.contains(e->pos())) {
+        if (m_mouseMoved) {
+            QMouseEvent pe = QMouseEvent(QEvent::MouseButtonPress, e->pos(), e->button(), e->buttons(), e->modifiers());
+            QQuickWindow::mousePressEvent(&pe);
+            QQuickWindow::mouseReleaseEvent(e);
+        }
+    } else {
         forwardEventToTransientParent(e);
+    }
 }
 
 void QtMenuPopupWindow::forwardEventToTransientParent(QMouseEvent *e)
 {
-    QWindow *parentMenuWindow = /*qobject_cast<QtMenuPopupWindow*>*/(transientParent());
-    if (!parentMenuWindow)
-        return;
-    QPoint parentPos = parentMenuWindow->mapFromGlobal(mapToGlobal(e->pos()));
-    QMouseEvent pe = QMouseEvent(e->type(), parentPos, e->button(), e->buttons(), e->modifiers());
-    QGuiApplication::sendEvent(parentMenuWindow, &pe);
+    QWindow *parentMenuWindow = qobject_cast<QtMenuPopupWindow*>(transientParent());
+    if (!parentMenuWindow) {
+        if (m_mouseMoved && e->type() == QEvent::MouseButtonRelease)
+            dismissMenu();
+    } else {
+        QPoint parentPos = parentMenuWindow->mapFromGlobal(mapToGlobal(e->pos()));
+        QMouseEvent pe = QMouseEvent(e->type(), parentPos, e->button(), e->buttons(), e->modifiers());
+        QGuiApplication::sendEvent(parentMenuWindow, &pe);
+    }
 }
 
 QT_END_NAMESPACE
diff --git a/src/controls/qtmenupopupwindow_p.h b/src/controls/qtmenupopupwindow_p.h
index 6c3fa19f..82a2a30e 100644
--- a/src/controls/qtmenupopupwindow_p.h
+++ b/src/controls/qtmenupopupwindow_p.h
@@ -67,14 +67,13 @@ Q_SIGNALS:
     void menuDismissed();
 
 protected:
-    void mousePressEvent(QMouseEvent *);
     void mouseReleaseEvent(QMouseEvent *);
     void mouseMoveEvent(QMouseEvent *);
 
 private:
     void forwardEventToTransientParent(QMouseEvent *);
 
-    bool m_pressedInside;
+    bool m_mouseMoved;
     const QQuickItem *m_itemAt;
     QPointF m_oldItemPos;
 };