Move action handlers to the Accessible attached object

With this change, instead of writing:

    function accessiblePressAction() { submit() }

You should write:

    Accessible.onPressAction: { submit() }

For the moment, only 4 actions are added:
press, toggle, increase and decrease.

The old style action handlers are deprecated, and removed from the
documentation. New style action handlers will be preferred in case an
item declares both styles.

Change-Id: I11919e631d8476d55540f94252757b911c44ade4
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@theqtcompany.com>

examples/quick/quick-accessibility/content/Button.qml

@@ -42,7 +42,7 @@ Rectangle {
     Accessible.name: text
     Accessible.description: "This button does " + text
     Accessible.role: Accessible.Button
-    function accessiblePressAction() {
+    Accessible.onPressAction: {
         button.clicked()
     }
     //! [button]

src/quick/accessible/qaccessiblequickitem.cpp

@@ -39,7 +39,6 @@
 #include "QtQuick/private/qquicktext_p.h"
 #include "QtQuick/private/qquickaccessibleattached_p.h"
 #include "QtQuick/qquicktextdocument.h"
-
 QT_BEGIN_NAMESPACE
 
 #ifndef QT_NO_ACCESSIBILITY
@@ -217,16 +216,24 @@ QStringList QAccessibleQuickItem::actionNames() const
     QStringList actions = QQmlAccessible::actionNames();
     if (state().focusable)
         actions.append(QAccessibleActionInterface::setFocusAction());
+
+    // ### The following can lead to duplicate action names. We'll fix that when we kill QQmlAccessible
+    if (QQuickAccessibleAttached *attached = QQuickAccessibleAttached::attachedProperties(item()))
+        attached->availableActions(&actions);
     return actions;
 }
 
 void QAccessibleQuickItem::doAction(const QString &actionName)
 {
+    bool accepted = false;
     if (actionName == QAccessibleActionInterface::setFocusAction()) {
         item()->forceActiveFocus();
-    } else {
-        QQmlAccessible::doAction(actionName);
+        accepted = true;
     }
+    if (QQuickAccessibleAttached *attached = QQuickAccessibleAttached::attachedProperties(item()))
+        accepted = attached->doAction(actionName);
+    if (!accepted)
+        QQmlAccessible::doAction(actionName);
 }
 
 QStringList QAccessibleQuickItem::keyBindingsForAction(const QString &actionName) const

src/quick/items/qquickaccessibleattached.cpp

@@ -69,7 +69,7 @@ QT_BEGIN_NAMESPACE
         Accessible.role: Accessible.Button
         Accessible.name: label.text
         Accessible.description: "shows the next page"
-        function accessiblePressAction() {
+        Accessible.onPressAction: {
             // do a button click
         }
     }
@@ -79,8 +79,8 @@ QT_BEGIN_NAMESPACE
     The name is a short and consise description of the control and should reflect the visual label.
     In this case it is not clear what the button does with the name only, so \l description contains
     an explanation.
-    There is also a function \c accessiblePressAction() which can be invoked by assistive tools to trigger
-    the button. This function needs to have the same effect as tapping or clicking the button would have.
+    There is also a signal handler \l {Accessible::pressAction}{Accessible.pressAction} which can be invoked by assistive tools to trigger
+    the button. This signal handler needs to have the same effect as tapping or clicking the button would have.
 
     \sa Accessibility
 */
@@ -117,7 +117,7 @@ QT_BEGIN_NAMESPACE
     \table
     \header
         \li \b {Role}
-        \li \b {Properties and functions}
+        \li \b {Properties and signals}
         \li \b {Explanation}
     \row
         \li All interactive elements
@@ -128,13 +128,14 @@ QT_BEGIN_NAMESPACE
             can be moved from item to item.
     \row
         \li Button, CheckBox, RadioButton
-        \li \c accessiblePressAction()
-        \li A button should have a function with the name \c accessiblePressAction.
-            This function may be called by an assistive tool such as a screen-reader.
+        \li \l {Accessible::pressAction}{Accessible.pressAction}
+        \li A button should have a signal handler with the name \c onPressAction.
+            This signal may be emitted by an assistive tool such as a screen-reader.
             The implementation needs to behave the same as a mouse click or tap on the button.
     \row
        \li CheckBox, RadioButton
-       \li \l checkable, \l checked
+       \li \l checkable, \l checked, \l {Accessible::toggleAction}{Accessible.toggleAction}
+
        \li The check state of the check box. Updated on Press, Check and Uncheck actions.
     \row
        \li Slider, SpinBox, Dial, ScrollBar
@@ -142,7 +143,7 @@ QT_BEGIN_NAMESPACE
        \li These properties reflect the state and possible values for the elements.
     \row
        \li Slider, SpinBox, Dial, ScrollBar
-       \li \c accessibleIncreaseAction(), \c accessibleDecreaseAction()
+       \li \l {Accessible::increaseAction}{Accessible.increaseAction}, \l {Accessible::decreaseAction}{Accessible.decreaseAction}
        \li Actions to increase and decrease the value of the element.
     \endtable
 */
@@ -262,6 +263,40 @@ QT_BEGIN_NAMESPACE
     By default this property is \c false.
 */
 
+/*!
+    \qmlsignal QtQuick::Accessible::pressAction()
+
+    This signal is emitted when a press action is received from an assistive tool such as a screen-reader.
+
+    The corresponding handler is \c onPressAction.
+*/
+/*!
+    \qmlsignal QtQuick::Accessible::toggleAction()
+
+    This signal is emitted when a toggle action is received from an assistive tool such as a screen-reader.
+
+    The corresponding handler is \c onToggleAction.
+*/
+/*!
+    \qmlsignal QtQuick::Accessible::increaseAction()
+
+    This signal is emitted when a increase action is received from an assistive tool such as a screen-reader.
+
+    The corresponding handler is \c onIncreaseAction.
+*/
+/*!
+    \qmlsignal QtQuick::Accessible::decreaseAction()
+
+    This signal is emitted when a decrease action is received from an assistive tool such as a screen-reader.
+
+    The corresponding handler is \c onDecreaseAction.
+*/
+
+const QMetaMethod QQuickAccessibleAttached::sigPress = QMetaMethod::fromSignal(&QQuickAccessibleAttached::pressAction);
+const QMetaMethod QQuickAccessibleAttached::sigToggle = QMetaMethod::fromSignal(&QQuickAccessibleAttached::toggleAction);
+const QMetaMethod QQuickAccessibleAttached::sigIncrease = QMetaMethod::fromSignal(&QQuickAccessibleAttached::increaseAction);
+const QMetaMethod QQuickAccessibleAttached::sigDecrease = QMetaMethod::fromSignal(&QQuickAccessibleAttached::decreaseAction);
+
 QQuickAccessibleAttached::QQuickAccessibleAttached(QObject *parent)
     : QObject(parent), m_role(QAccessible::NoRole)
 {
@@ -306,6 +341,35 @@ void QQuickAccessibleAttached::setIgnored(bool ignored)
     }
 }
 
+bool QQuickAccessibleAttached::doAction(const QString &actionName)
+{
+    const QMetaMethod *sig = 0;
+    if (actionName == QAccessibleActionInterface::pressAction())
+        sig = &sigPress;
+    else if (actionName == QAccessibleActionInterface::toggleAction())
+        sig = &sigToggle;
+    else if (actionName == QAccessibleActionInterface::increaseAction())
+        sig = &sigIncrease;
+    else if (actionName == QAccessibleActionInterface::decreaseAction())
+        sig = &sigDecrease;
+
+    if (sig && isSignalConnected(*sig))
+        return sig->invoke(this);
+    return false;
+}
+
+void QQuickAccessibleAttached::availableActions(QStringList *actions) const
+{
+    if (isSignalConnected(sigPress))
+        actions->append(QAccessibleActionInterface::pressAction());
+    if (isSignalConnected(sigToggle))
+        actions->append(QAccessibleActionInterface::toggleAction());
+    if (isSignalConnected(sigIncrease))
+        actions->append(QAccessibleActionInterface::increaseAction());
+    if (isSignalConnected(sigDecrease))
+        actions->append(QAccessibleActionInterface::decreaseAction());
+}
+
 QT_END_NAMESPACE
 
 #endif

src/quick/items/qquickaccessibleattached_p.h

@@ -188,6 +188,8 @@ public:
 
     QAccessible::State state() { return m_state; }
     bool ignored() const;
+    bool doAction(const QString &actionName);
+    void availableActions(QStringList *actions) const;
 
 public Q_SLOTS:
     void valueChanged() {
@@ -206,6 +208,10 @@ Q_SIGNALS:
     void nameChanged();
     void descriptionChanged();
     void ignoredChanged();
+    void pressAction();
+    void toggleAction();
+    void increaseAction();
+    void decreaseAction();
 
 private:
     QQuickItem *item() const { return static_cast<QQuickItem*>(parent()); }
@@ -215,6 +221,11 @@ private:
     QString m_name;
     QString m_description;
 
+    static const QMetaMethod sigPress;
+    static const QMetaMethod sigToggle;
+    static const QMetaMethod sigIncrease;
+    static const QMetaMethod sigDecrease;
+
 public:
     using QObject::property;
 };

tests/manual/accessibility/textandbuttons.qml

@@ -50,9 +50,8 @@ Rectangle {
 
         Accessible.role : Accessible.Button
 
-        function accessibleAction(action) {
-            if (action == Qt.Press)
-                buttonAction()
+        Accessible.onPressAction: {
+            buttonAction()
         }
 
         function buttonAction() {