Android A11Y: handle valueChanged events

Before this patch Android A11Y implementation was missing
ValueChanged event handling. As a result, no update was given
when the element's value was changed.

Handling these events allows us to announce value changes on such
objects like Slider, SpinBox, etc...
This is a universal method of value-change announcement, so it
supports all sorts of A11Y gestures.

On the Java side a new function was introduced to announce the
values, because we need to use the actual element's *value*,
not its accessible name or description.

Task-number: QTBUG-93396
Pick-to: 6.3 6.2 5.15
Change-Id: Ic44abd5f01b9b6f5468962131466edaf6a49d498
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
Reviewed-by: Rami Potinkara <rami.potinkara@qt.io>

4 files changed, 55 insertions, 0 deletions

diff --git a/src/android/jar/src/org/qtproject/qt/android/QtActivityDelegate.java b/src/android/jar/src/org/qtproject/qt/android/QtActivityDelegate.java
index 83f86b0d97..fe76d731fd 100644
--- a/src/android/jar/src/org/qtproject/qt/android/QtActivityDelegate.java
+++ b/src/android/jar/src/org/qtproject/qt/android/QtActivityDelegate.java
@@ -921,6 +921,13 @@ public class QtActivityDelegate
         m_accessibilityDelegate.notifyObjectFocus(viewId);
     }
 
+    public void notifyValueChanged(int viewId, String value)
+    {
+        if (m_accessibilityDelegate == null)
+            return;
+        m_accessibilityDelegate.notifyValueChanged(viewId, value);
+    }
+
     public void notifyQtAndroidPluginRunning(boolean running)
     {
         m_isPluginRunning = running;
diff --git a/src/android/jar/src/org/qtproject/qt/android/QtNative.java b/src/android/jar/src/org/qtproject/qt/android/QtNative.java
index ccf18ca0a6..c7eb71bb50 100644
--- a/src/android/jar/src/org/qtproject/qt/android/QtNative.java
+++ b/src/android/jar/src/org/qtproject/qt/android/QtNative.java
@@ -998,6 +998,18 @@ public class QtNative
         });
     }
 
+    private static void notifyValueChanged(int viewId, String value)
+    {
+        runAction(new Runnable() {
+            @Override
+            public void run() {
+                if (m_activityDelegate != null) {
+                    m_activityDelegate.notifyValueChanged(viewId, value);
+                }
+            }
+        });
+    }
+
     public static void notifyQtAndroidPluginRunning(final boolean running)
     {
         m_activityDelegate.notifyQtAndroidPluginRunning(running);
diff --git a/src/android/jar/src/org/qtproject/qt/android/accessibility/QtAccessibilityDelegate.java b/src/android/jar/src/org/qtproject/qt/android/accessibility/QtAccessibilityDelegate.java
index 4d72e9a680..c5f5fb92e6 100644
--- a/src/android/jar/src/org/qtproject/qt/android/accessibility/QtAccessibilityDelegate.java
+++ b/src/android/jar/src/org/qtproject/qt/android/accessibility/QtAccessibilityDelegate.java
@@ -225,6 +225,41 @@ public class QtAccessibilityDelegate extends View.AccessibilityDelegate
                 AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
     }
 
+    public void notifyValueChanged(int viewId, String value)
+    {
+        // Send a TYPE_ANNOUNCEMENT event with the new value
+
+        if ((viewId == INVALID_ID) || !m_manager.isEnabled()) {
+            Log.w(TAG, "notifyValueChanged() for invalid view");
+            return;
+        }
+
+        final ViewGroup group = (ViewGroup)m_view.getParent();
+        if (group == null) {
+            Log.w(TAG, "Could not announce value because ViewGroup was null.");
+            return;
+        }
+
+        final AccessibilityEvent event =
+                AccessibilityEvent.obtain(AccessibilityEvent.TYPE_ANNOUNCEMENT);
+
+        event.setEnabled(true);
+        event.setClassName(m_view.getClass().getName() + DEFAULT_CLASS_NAME);
+
+        event.setContentDescription(value);
+
+        if (event.getText().isEmpty() && TextUtils.isEmpty(event.getContentDescription())) {
+            Log.w(TAG, "No value to announce for " + event.getClassName());
+            return;
+        }
+
+        event.setPackageName(m_view.getContext().getPackageName());
+        event.setSource(m_view, viewId);
+
+        if (!group.requestSendAccessibilityEvent(m_view, event))
+            Log.w(TAG, "Failed to send value change announcement for " + event.getClassName());
+    }
+
     public boolean sendEventForVirtualViewId(int virtualViewId, int eventType)
     {
         if ((virtualViewId == INVALID_ID) || !m_manager.isEnabled()) {
diff --git a/src/android/jar/src/org/qtproject/qt/android/accessibility/QtNativeAccessibility.java b/src/android/jar/src/org/qtproject/qt/android/accessibility/QtNativeAccessibility.java
index aa6f7c5a67..c574291708 100644
--- a/src/android/jar/src/org/qtproject/qt/android/accessibility/QtNativeAccessibility.java
+++ b/src/android/jar/src/org/qtproject/qt/android/accessibility/QtNativeAccessibility.java
@@ -55,4 +55,5 @@ class QtNativeAccessibility
     static native boolean scrollBackward(int objectId);
 
     static native boolean populateNode(int objectId, AccessibilityNodeInfo node);
+    static native String valueForAccessibleObject(int objectId);
 }