Android: Propagate a11y ObjectShow events to screen reader

Sending an ObjectShow event, e.g. by setting QQuickItem::visible to
true, has to trigger a refresh of the screen reader hierarchy. If the
signal is ignored the source of the signal will be ignored by the
screen reader.

Fixes: QTBUG-122436
Pick-to: 6.5
Change-Id: I32ee2e8b2602cd0dd9b9a83ff1fe426d88d137a8
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
(cherry picked from commit efd00066b42d9cbd3a85336f4851213d94cdc28e)

src/android/jar/src/org/qtproject/qt/android/QtActivityDelegateBase.java

@@ -176,6 +176,14 @@ abstract class QtActivityDelegateBase
         m_accessibilityDelegate.notifyObjectHide(viewId, parentId);
     }
 
+    @UsedFromNativeCode
+    public void notifyObjectShow(int parentId)
+    {
+        if (m_accessibilityDelegate == null)
+           return;
+        m_accessibilityDelegate.notifyObjectShow(parentId);
+    }
+
     @UsedFromNativeCode
     public void notifyObjectFocus(int viewId)
     {

src/android/jar/src/org/qtproject/qt/android/accessibility/QtAccessibilityDelegate.java

@@ -191,6 +191,15 @@ public class QtAccessibilityDelegate extends View.AccessibilityDelegate
         });
     }
 
+    public void notifyObjectShow(int parentId)
+    {
+        QtNative.runAction(() -> {
+            // When the object is shown, we need to notify its parent about
+            // content change, not the shown object itself
+            invalidateVirtualViewId(parentId);
+        });
+    }
+
     public void notifyObjectFocus(int viewId)
     {
         QtNative.runAction(() -> {

src/plugins/platforms/android/androidjniaccessibility.cpp

@@ -127,6 +127,12 @@ namespace QtAndroidAccessibility
         QtAndroid::notifyObjectHide(accessibilityObjectId, parentObjectId);
     }
 
+    void notifyObjectShow(uint accessibilityObjectId)
+    {
+        const auto parentObjectId = parentId_helper(accessibilityObjectId);
+        QtAndroid::notifyObjectShow(parentObjectId);
+    }
+
     void notifyObjectFocus(uint accessibilityObjectId)
     {
         QtAndroid::notifyObjectFocus(accessibilityObjectId);

src/plugins/platforms/android/androidjniaccessibility.h

@@ -18,6 +18,7 @@ namespace QtAndroidAccessibility
     bool registerNatives(QJniEnvironment &env);
     void notifyLocationChange(uint accessibilityObjectId);
     void notifyObjectHide(uint accessibilityObjectId);
+    void notifyObjectShow(uint accessibilityObjectId);
     void notifyObjectFocus(uint accessibilityObjectId);
     void notifyValueChanged(uint accessibilityObjectId);
     void notifyScrolledEvent(uint accessibilityObjectId);

src/plugins/platforms/android/androidjnimain.cpp

@@ -245,6 +245,12 @@ namespace QtAndroid
                                               accessibilityObjectId, parentObjectId);
     }
 
+    void notifyObjectShow(uint parentObjectId)
+    {
+        qtActivityDelegate().callMethod<void>("notifyObjectShow",
+                                              parentObjectId);
+    }
+
     void notifyObjectFocus(uint accessibilityObjectId)
     {
         qtActivityDelegate().callMethod<void>("notifyObjectFocus", accessibilityObjectId);

src/plugins/platforms/android/androidjnimain.h

@@ -65,6 +65,7 @@ namespace QtAndroid
 
     void notifyAccessibilityLocationChange(uint accessibilityObjectId);
     void notifyObjectHide(uint accessibilityObjectId, uint parentObjectId);
+    void notifyObjectShow(uint parentObjectId);
     void notifyObjectFocus(uint accessibilityObjectId);
     void notifyValueChanged(uint accessibilityObjectId, jstring value);
     void notifyScrolledEvent(uint accessibilityObjectId);

src/plugins/platforms/android/qandroidplatformaccessibility.cpp

@@ -28,6 +28,8 @@ void QAndroidPlatformAccessibility::notifyAccessibilityUpdate(QAccessibleEvent *
         QtAndroidAccessibility::notifyLocationChange(event->uniqueId());
     } else if (event->type() == QAccessible::ObjectHide) {
         QtAndroidAccessibility::notifyObjectHide(event->uniqueId());
+    } else if (event->type() == QAccessible::ObjectShow) {
+        QtAndroidAccessibility::notifyObjectShow(event->uniqueId());
     } else if (event->type() == QAccessible::Focus) {
         QtAndroidAccessibility::notifyObjectFocus(event->uniqueId());
     } else if (event->type() == QAccessible::ValueChanged) {