Make hoverEnabled propagate to children

Hover effects can be sometimes a bit disturbing. This change makes it
possible to conveniently disable hover effects for a tree of controls
in one go. For example, to disable hover effects for a page including
its header, footer, and all list items:

    Page {
        hoverEnabled: false
        header: ...
        footer: ...
        ListView {
            delegate: ...
        }
    }

[ChangeLog][Controls][Important Behavior Changes] Control::hoverEnabled
has been made to inherit to children, to make it possible to disable
hover effects for a tree of controls in one place.

Change-Id: Ia87144f2cc04957a32f89d3313816b91d97db635
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: J-P Nurmi <jpnurmi@qt.io>
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

10 files changed, 166 insertions, 18 deletions

diff --git a/src/quicktemplates2/qquickcontrol.cpp b/src/quicktemplates2/qquickcontrol.cpp
index e89cc54d..1db532b9 100644
--- a/src/quicktemplates2/qquickcontrol.cpp
+++ b/src/quicktemplates2/qquickcontrol.cpp
@@ -109,7 +109,8 @@ QQuickControlPrivate::ExtraData::ExtraData()
 }
 
 QQuickControlPrivate::QQuickControlPrivate() :
-    hasTopPadding(false), hasLeftPadding(false), hasRightPadding(false), hasBottomPadding(false), hasLocale(false), hovered(false), wheelEnabled(false),
+    hasTopPadding(false), hasLeftPadding(false), hasRightPadding(false), hasBottomPadding(false),
+    hasLocale(false), hovered(false), wheelEnabled(false), explicitHoverEnabled(false),
     padding(0), topPadding(0), leftPadding(0), rightPadding(0), bottomPadding(0), spacing(0),
     focusPolicy(Qt::NoFocus), focusReason(Qt::OtherFocusReason),
     background(nullptr), contentItem(nullptr), accessibleAttached(nullptr)
@@ -361,6 +362,62 @@ void QQuickControlPrivate::updateFontRecur(QQuickItem *item, const QFont &f)
     }
 }
 
+void QQuickControlPrivate::updateHoverEnabled(bool enabled, bool xplicit)
+{
+    Q_Q(QQuickControl);
+    if (!xplicit && explicitHoverEnabled)
+        return;
+
+    bool wasEnabled = q->isHoverEnabled();
+    explicitHoverEnabled = xplicit;
+    if (wasEnabled != enabled) {
+        q->setAcceptHoverEvents(enabled);
+        QQuickControlPrivate::updateHoverEnabledRecur(q, enabled);
+        emit q->hoverEnabledChanged();
+    }
+}
+
+void QQuickControlPrivate::updateHoverEnabledRecur(QQuickItem *item, bool enabled)
+{
+    const auto childItems = item->childItems();
+    for (QQuickItem *child : childItems) {
+        if (QQuickControl *control = qobject_cast<QQuickControl *>(child))
+            QQuickControlPrivate::get(control)->updateHoverEnabled(enabled, false);
+        else
+            updateHoverEnabledRecur(child, enabled);
+    }
+}
+
+bool QQuickControlPrivate::calcHoverEnabled(const QQuickItem *item)
+{
+    const QQuickItem *p = item;
+    while (p) {
+        // QQuickPopupItem accepts hover events to avoid leaking them through.
+        // Don't inherit that to the children of the popup, but fallback to the
+        // environment variable or style hint.
+        if (qobject_cast<const QQuickPopupItem *>(p))
+            break;
+
+        if (const QQuickControl *control = qobject_cast<const QQuickControl *>(p))
+            return control->isHoverEnabled();
+
+        QVariant v = p->property("hoverEnabled");
+        if (v.isValid() && v.userType() == QMetaType::Bool)
+            return v.toBool();
+
+        p = p->parentItem();
+    }
+
+    bool ok = false;
+    int env = qEnvironmentVariableIntValue("QT_QUICK_CONTROLS_HOVER_ENABLED", &ok);
+    if (ok)
+        return env != 0;
+
+    // TODO: QQuickApplicationWindow::isHoverEnabled()
+
+    return QGuiApplication::styleHints()->useHoverEffects();
+}
+
 QString QQuickControl::accessibleName() const
 {
 #ifndef QT_NO_ACCESSIBILITY
@@ -429,6 +486,8 @@ void QQuickControl::itemChange(QQuickItem::ItemChange change, const QQuickItem::
             d->resolveFont();
             if (!d->hasLocale)
                 d->updateLocale(QQuickControlPrivate::calcLocale(d->parentItem), false); // explicit=false
+            if (!d->explicitHoverEnabled)
+                d->updateHoverEnabled(QQuickControlPrivate::calcHoverEnabled(d->parentItem), false); // explicit=false
         }
         break;
     case ItemActiveFocusHasChanged:
@@ -958,7 +1017,11 @@ void QQuickControl::setHovered(bool hovered)
 /*!
     \qmlproperty bool QtQuick.Controls::Control::hoverEnabled
 
-    This property determines whether the control accepts hover events. The default value is \c false.
+    This property determines whether the control accepts hover events. The default value
+    is \c Qt.styleHints.useHoverEffects.
+
+    Setting this property propagates the value to all child controls that do not have
+    \c hoverEnabled explicitly set.
 
     \sa hovered
 */
@@ -971,11 +1034,20 @@ bool QQuickControl::isHoverEnabled() const
 void QQuickControl::setHoverEnabled(bool enabled)
 {
     Q_D(QQuickControl);
-    if (enabled == d->hoverEnabled)
+    if (d->explicitHoverEnabled && enabled == d->hoverEnabled)
+        return;
+
+    d->updateHoverEnabled(enabled, true); // explicit=true
+}
+
+void QQuickControl::resetHoverEnabled()
+{
+    Q_D(QQuickControl);
+    if (!d->explicitHoverEnabled)
         return;
 
-    setAcceptHoverEvents(enabled);
-    emit hoverEnabledChanged();
+    d->explicitHoverEnabled = false;
+    d->updateHoverEnabled(QQuickControlPrivate::calcHoverEnabled(d->parentItem), false); // explicit=false
 }
 
 /*!
@@ -1122,6 +1194,8 @@ void QQuickControl::componentComplete()
     QQuickItem::componentComplete();
     if (!d->hasLocale)
         d->locale = QQuickControlPrivate::calcLocale(d->parentItem);
+    if (!d->explicitHoverEnabled)
+        setAcceptHoverEvents(QQuickControlPrivate::calcHoverEnabled(d->parentItem));
 #ifndef QT_NO_ACCESSIBILITY
     if (!d->accessibleAttached && QAccessible::isActive())
         accessibilityActiveChanged(true);
diff --git a/src/quicktemplates2/qquickcontrol_p.h b/src/quicktemplates2/qquickcontrol_p.h
index 9027743a..81dd615f 100644
--- a/src/quicktemplates2/qquickcontrol_p.h
+++ b/src/quicktemplates2/qquickcontrol_p.h
@@ -74,7 +74,7 @@ class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickControl : public QQuickItem
     Q_PROPERTY(Qt::FocusReason focusReason READ focusReason WRITE setFocusReason NOTIFY focusReasonChanged FINAL)
     Q_PROPERTY(bool visualFocus READ hasVisualFocus NOTIFY visualFocusChanged FINAL)
     Q_PROPERTY(bool hovered READ isHovered NOTIFY hoveredChanged FINAL)
-    Q_PROPERTY(bool hoverEnabled READ isHoverEnabled WRITE setHoverEnabled NOTIFY hoverEnabledChanged FINAL)
+    Q_PROPERTY(bool hoverEnabled READ isHoverEnabled WRITE setHoverEnabled RESET resetHoverEnabled NOTIFY hoverEnabledChanged FINAL)
     Q_PROPERTY(bool wheelEnabled READ isWheelEnabled WRITE setWheelEnabled NOTIFY wheelEnabledChanged FINAL)
     Q_PROPERTY(QQuickItem *background READ background WRITE setBackground NOTIFY backgroundChanged FINAL)
     Q_PROPERTY(QQuickItem *contentItem READ contentItem WRITE setContentItem NOTIFY contentItemChanged FINAL)
@@ -132,6 +132,7 @@ public:
 
     bool isHoverEnabled() const;
     void setHoverEnabled(bool enabled);
+    void resetHoverEnabled();
 
     bool isWheelEnabled() const;
     void setWheelEnabled(bool enabled);
diff --git a/src/quicktemplates2/qquickcontrol_p_p.h b/src/quicktemplates2/qquickcontrol_p_p.h
index 26760510..cae1ae59 100644
--- a/src/quicktemplates2/qquickcontrol_p_p.h
+++ b/src/quicktemplates2/qquickcontrol_p_p.h
@@ -111,6 +111,10 @@ public:
     static void updateLocaleRecur(QQuickItem *item, const QLocale &l);
     static QLocale calcLocale(const QQuickItem *item);
 
+    void updateHoverEnabled(bool enabled, bool xplicit);
+    static void updateHoverEnabledRecur(QQuickItem *item, bool enabled);
+    static bool calcHoverEnabled(const QQuickItem *item);
+
     void deleteDelegate(QObject *object);
 
     struct ExtraData {
@@ -131,6 +135,7 @@ public:
     bool hasLocale;
     bool hovered;
     bool wheelEnabled;
+    bool explicitHoverEnabled;
     qreal padding;
     qreal topPadding;
     qreal leftPadding;
diff --git a/src/quicktemplates2/qquickpopup.cpp b/src/quicktemplates2/qquickpopup.cpp
index 45d0e67c..3f7d6907 100644
--- a/src/quicktemplates2/qquickpopup.cpp
+++ b/src/quicktemplates2/qquickpopup.cpp
@@ -406,7 +406,7 @@ QQuickPopupItem::QQuickPopupItem(QQuickPopup *popup) :
     setAcceptedMouseButtons(Qt::AllButtons);
 
     // TODO: switch to QStyleHints::useHoverEffects in Qt 5.8
-    setAcceptHoverEvents(true);
+    setHoverEnabled(true);
     // setAcceptHoverEvents(QGuiApplication::styleHints()->useHoverEffects());
     // connect(QGuiApplication::styleHints(), &QStyleHints::useHoverEffectsChanged, this, &QQuickItem::setAcceptHoverEvents);
 }
diff --git a/src/quicktemplates2/qquicktextarea.cpp b/src/quicktemplates2/qquicktextarea.cpp
index 92c85941..41980073 100644
--- a/src/quicktemplates2/qquicktextarea.cpp
+++ b/src/quicktemplates2/qquicktextarea.cpp
@@ -131,7 +131,8 @@ QT_BEGIN_NAMESPACE
 */
 
 QQuickTextAreaPrivate::QQuickTextAreaPrivate()
-    : hovered(false), background(nullptr), focusReason(Qt::OtherFocusReason), accessibleAttached(nullptr), flickable(nullptr)
+    : hovered(false), explicitHoverEnabled(false), background(nullptr),
+      focusReason(Qt::OtherFocusReason), accessibleAttached(nullptr), flickable(nullptr)
 {
 #ifndef QT_NO_ACCESSIBILITY
     QAccessible::installActivationObserver(this);
@@ -355,6 +356,21 @@ void QQuickTextAreaPrivate::inheritFont(const QFont &f)
         emit q->fontChanged();
 }
 
+void QQuickTextAreaPrivate::updateHoverEnabled(bool enabled, bool xplicit)
+{
+    Q_Q(QQuickTextArea);
+    if (!xplicit && explicitHoverEnabled)
+        return;
+
+    bool wasEnabled = q->isHoverEnabled();
+    explicitHoverEnabled = xplicit;
+    if (wasEnabled != enabled) {
+        q->setAcceptHoverEvents(enabled);
+        QQuickControlPrivate::updateHoverEnabledRecur(q, enabled);
+        emit q->hoverEnabledChanged();
+    }
+}
+
 void QQuickTextAreaPrivate::_q_readOnlyChanged(bool isReadOnly)
 {
 #ifndef QT_NO_ACCESSIBILITY
@@ -549,11 +565,20 @@ bool QQuickTextArea::isHoverEnabled() const
 void QQuickTextArea::setHoverEnabled(bool enabled)
 {
     Q_D(QQuickTextArea);
-    if (enabled == d->hoverEnabled)
+    if (d->explicitHoverEnabled && enabled == d->hoverEnabled)
         return;
 
-    setAcceptHoverEvents(enabled);
-    emit hoverEnabledChanged();
+    d->updateHoverEnabled(enabled, true); // explicit=true
+}
+
+void QQuickTextArea::resetHoverEnabled()
+{
+    Q_D(QQuickTextArea);
+    if (!d->explicitHoverEnabled)
+        return;
+
+    d->explicitHoverEnabled = false;
+    d->updateHoverEnabled(QQuickControlPrivate::calcHoverEnabled(d->parentItem), false); // explicit=false
 }
 
 bool QQuickTextArea::contains(const QPointF &point) const
@@ -575,6 +600,8 @@ void QQuickTextArea::componentComplete()
 {
     Q_D(QQuickTextArea);
     QQuickTextEdit::componentComplete();
+    if (!d->explicitHoverEnabled)
+        setAcceptHoverEvents(QQuickControlPrivate::calcHoverEnabled(d->parentItem));
 #ifndef QT_NO_ACCESSIBILITY
     if (!d->accessibleAttached && QAccessible::isActive())
         d->accessibilityActiveChanged(true);
@@ -588,8 +615,11 @@ void QQuickTextArea::itemChange(QQuickItem::ItemChange change, const QQuickItem:
 {
     Q_D(QQuickTextArea);
     QQuickTextEdit::itemChange(change, value);
-    if (change == ItemParentHasChanged && value.item)
+    if (change == ItemParentHasChanged && value.item) {
         d->resolveFont();
+        if (!d->explicitHoverEnabled)
+            d->updateHoverEnabled(QQuickControlPrivate::calcHoverEnabled(d->parentItem), false); // explicit=false
+    }
 }
 
 void QQuickTextArea::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry)
diff --git a/src/quicktemplates2/qquicktextarea_p.h b/src/quicktemplates2/qquicktextarea_p.h
index 20500ee6..35bddba0 100644
--- a/src/quicktemplates2/qquicktextarea_p.h
+++ b/src/quicktemplates2/qquicktextarea_p.h
@@ -68,7 +68,7 @@ class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickTextArea : public QQuickTextEdit
     Q_PROPERTY(QString placeholderText READ placeholderText WRITE setPlaceholderText NOTIFY placeholderTextChanged FINAL)
     Q_PROPERTY(Qt::FocusReason focusReason READ focusReason WRITE setFocusReason NOTIFY focusReasonChanged FINAL)
     Q_PROPERTY(bool hovered READ isHovered NOTIFY hoveredChanged FINAL REVISION 1)
-    Q_PROPERTY(bool hoverEnabled READ isHoverEnabled WRITE setHoverEnabled NOTIFY hoverEnabledChanged FINAL REVISION 1)
+    Q_PROPERTY(bool hoverEnabled READ isHoverEnabled WRITE setHoverEnabled RESET resetHoverEnabled NOTIFY hoverEnabledChanged FINAL REVISION 1)
 
 public:
     explicit QQuickTextArea(QQuickItem *parent = nullptr);
@@ -93,6 +93,7 @@ public:
 
     bool isHoverEnabled() const;
     void setHoverEnabled(bool enabled);
+    void resetHoverEnabled();
 
     bool contains(const QPointF &point) const override;
 
diff --git a/src/quicktemplates2/qquicktextarea_p_p.h b/src/quicktemplates2/qquicktextarea_p_p.h
index 3ffa29bc..ed74ac9a 100644
--- a/src/quicktemplates2/qquicktextarea_p_p.h
+++ b/src/quicktemplates2/qquicktextarea_p_p.h
@@ -81,6 +81,8 @@ public:
     void resolveFont();
     void inheritFont(const QFont &f);
 
+    void updateHoverEnabled(bool h, bool e);
+
     void attachFlickable(QQuickFlickable *flickable);
     void detachFlickable();
     void ensureCursorVisible();
@@ -105,6 +107,7 @@ public:
     void deleteDelegate(QObject *object);
 
     bool hovered;
+    bool explicitHoverEnabled;
     QFont font;
     QQuickItem *background;
     QString placeholder;
diff --git a/src/quicktemplates2/qquicktextfield.cpp b/src/quicktemplates2/qquicktextfield.cpp
index 0ca0c6ce..8bdbe3cb 100644
--- a/src/quicktemplates2/qquicktextfield.cpp
+++ b/src/quicktemplates2/qquicktextfield.cpp
@@ -115,6 +115,7 @@ QT_BEGIN_NAMESPACE
 
 QQuickTextFieldPrivate::QQuickTextFieldPrivate()
     : hovered(false)
+    , explicitHoverEnabled(false)
     , background(nullptr)
     , focusReason(Qt::OtherFocusReason)
     , accessibleAttached(nullptr)
@@ -221,6 +222,21 @@ void QQuickTextFieldPrivate::inheritFont(const QFont &f)
         emit q->fontChanged();
 }
 
+void QQuickTextFieldPrivate::updateHoverEnabled(bool enabled, bool xplicit)
+{
+    Q_Q(QQuickTextField);
+    if (!xplicit && explicitHoverEnabled)
+        return;
+
+    bool wasEnabled = q->isHoverEnabled();
+    explicitHoverEnabled = xplicit;
+    if (wasEnabled != enabled) {
+        q->setAcceptHoverEvents(enabled);
+        QQuickControlPrivate::updateHoverEnabledRecur(q, enabled);
+        emit q->hoverEnabledChanged();
+    }
+}
+
 void QQuickTextFieldPrivate::_q_readOnlyChanged(bool isReadOnly)
 {
 #ifndef QT_NO_ACCESSIBILITY
@@ -430,11 +446,20 @@ bool QQuickTextField::isHoverEnabled() const
 void QQuickTextField::setHoverEnabled(bool enabled)
 {
     Q_D(QQuickTextField);
-    if (enabled == d->hoverEnabled)
+    if (d->explicitHoverEnabled && enabled == d->hoverEnabled)
         return;
 
-    setAcceptHoverEvents(enabled);
-    emit hoverEnabledChanged();
+    d->updateHoverEnabled(enabled, true); // explicit=true
+}
+
+void QQuickTextField::resetHoverEnabled()
+{
+    Q_D(QQuickTextField);
+    if (!d->explicitHoverEnabled)
+        return;
+
+    d->explicitHoverEnabled = false;
+    d->updateHoverEnabled(QQuickControlPrivate::calcHoverEnabled(d->parentItem), false); // explicit=false
 }
 
 void QQuickTextField::classBegin()
@@ -448,6 +473,8 @@ void QQuickTextField::componentComplete()
 {
     Q_D(QQuickTextField);
     QQuickTextInput::componentComplete();
+    if (!d->explicitHoverEnabled)
+        setAcceptHoverEvents(QQuickControlPrivate::calcHoverEnabled(d->parentItem));
 #ifndef QT_NO_ACCESSIBILITY
     if (!d->accessibleAttached && QAccessible::isActive())
         d->accessibilityActiveChanged(true);
@@ -461,8 +488,11 @@ void QQuickTextField::itemChange(QQuickItem::ItemChange change, const QQuickItem
 {
     Q_D(QQuickTextField);
     QQuickTextInput::itemChange(change, value);
-    if (change == ItemParentHasChanged && value.item)
+    if (change == ItemParentHasChanged && value.item) {
         d->resolveFont();
+        if (!d->explicitHoverEnabled)
+            d->updateHoverEnabled(QQuickControlPrivate::calcHoverEnabled(d->parentItem), false); // explicit=false
+    }
 }
 
 void QQuickTextField::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry)
diff --git a/src/quicktemplates2/qquicktextfield_p.h b/src/quicktemplates2/qquicktextfield_p.h
index 5ef7a02d..57521592 100644
--- a/src/quicktemplates2/qquicktextfield_p.h
+++ b/src/quicktemplates2/qquicktextfield_p.h
@@ -67,7 +67,7 @@ class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickTextField : public QQuickTextInput
     Q_PROPERTY(QString placeholderText READ placeholderText WRITE setPlaceholderText NOTIFY placeholderTextChanged FINAL)
     Q_PROPERTY(Qt::FocusReason focusReason READ focusReason WRITE setFocusReason NOTIFY focusReasonChanged FINAL)
     Q_PROPERTY(bool hovered READ isHovered NOTIFY hoveredChanged FINAL REVISION 1)
-    Q_PROPERTY(bool hoverEnabled READ isHoverEnabled WRITE setHoverEnabled NOTIFY hoverEnabledChanged FINAL REVISION 1)
+    Q_PROPERTY(bool hoverEnabled READ isHoverEnabled WRITE setHoverEnabled RESET resetHoverEnabled NOTIFY hoverEnabledChanged FINAL REVISION 1)
 
 public:
     explicit QQuickTextField(QQuickItem *parent = nullptr);
@@ -90,6 +90,7 @@ public:
 
     bool isHoverEnabled() const;
     void setHoverEnabled(bool enabled);
+    void resetHoverEnabled();
 
 Q_SIGNALS:
     void fontChanged();
diff --git a/src/quicktemplates2/qquicktextfield_p_p.h b/src/quicktemplates2/qquicktextfield_p_p.h
index 99e1c48c..fb973ad4 100644
--- a/src/quicktemplates2/qquicktextfield_p_p.h
+++ b/src/quicktemplates2/qquicktextfield_p_p.h
@@ -79,6 +79,8 @@ public:
     void resolveFont();
     void inheritFont(const QFont &f);
 
+    void updateHoverEnabled(bool h, bool e);
+
     qreal getImplicitWidth() const override;
     qreal getImplicitHeight() const override;
 
@@ -96,6 +98,7 @@ public:
     void deleteDelegate(QObject *object);
 
     bool hovered;
+    bool explicitHoverEnabled;
     QFont font;
     QQuickItem *background;
     QString placeholder;