Android AccessibilityDelegate force reading of ViewGroup not children

Question

I'm using a viewpager which is made up of some number of relative layout siblings which are quite complex.

If I click on the relative layout, it will highlight the entire page and read the title and a few textviews one after the other as expected.

If I scroll the viewpager I'd like talkback to read the next page in the same way it reads the first if I click. Secondly, if I scroll to the second, third, etc. pages and click on those layouts, talkback will read as expected.

I am trying to achieve the click behavior after the scroll event has completed.

Here is what I have for the accessibilityDelegate.

    viewPager.setAccessibilityDelegate(new AccessibilityDelegate () {
        @Override
        public boolean onRequestSendAccessibilityEvent(ViewGroup host, View child, AccessibilityEvent event) {
            if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_SCROLLED) {
                View page = viewPager.getCurrentPageView();
                performAccessibilityAction(page, AccessibilityNodeInfo.ACTION_CLICK, Bundle.EMPTY);
            }
            return super.onRequestSendAccessibilityEvent(host, child, event);
        }
    });

I've verified that 'page' is the RelativeLayout parent that I think it is. I've also confirmed that the onRequestSendAccessibilityEvent is being fired, but it doesn't read the contents of its children. Am I missing something?

Updated

I've also tried using

viewpager.getCurrentPageView().sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_FOCUSED);

The above worked for another example when I needed to force talkback to reread a single item but does not have any affect if I try it on the page.

Thanks

Answer 1

Some background -- When you tap on the relative layout, TalkBack generates speech based on the layout's contents. On ICS, this is triggered by a HOVER_ENTER event. On Jelly Bean, it's triggered by an ACCESSIBILITY_FOCUS event. These events are sent automatically by the framework and should, generally speaking, never be sent manually from an app. The same goes for FOCUS events, except in the special case of custom views (see Accessibility talk from Google I/O 2013 for more details).

So, back on topic.

You can control the speech for SCROLLED events by populating the outgoing event with the text you want read. The down side of this is that you'll need to manually generate the text you want read, and it's very likely that this text will differ from what TalkBack will read if the user touches the layout.

viewPager.setAccessibilityDelegate(new AccessibilityDelegate () {
    @Override
    public void onPopulateAccessibilityEvent(View host, AccessibilityEvent event) {
        super.onPopulateAccessibilityEvent(host, event);

        if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_SCROLLED) {
            event.setContentDescription(/** your text */);
        }
    }
});

Another option is to do nothing and let the user explore the view on their own. This is the preferred interaction model for Android accessibility.

Edit: Video URL is broken, Changed.