Android通过点击ActionBar按钮触发自定义可访问性事件

Question

我正在尝试使用AccessibilityManager和TalkBack触发自定义AccessibilityEvent。

该事件的用例是，当用户单击操作栏时，片段会轮询对象列表，然后根据列表的大小调整其 AccessibilityEvent 内容。

当我尝试运行它时，我没有收到预期的Talkback消息。我很确定我在实例化AccessibilityEvent时错过了一些基本的东西。

我也不确定我是否需要使用，或者如何在这里应用AccessibilityServers，因为回调来自MenuItem而不是View。我知道我可以调用findViewById来获取此MenuItem的视图，但我对这些API不是很了解。

关于这两点的任何指导都是非常好的！

所讨论的问题基本上由以下伪代码描述：

public class MyFragment extends Fragment {

//...

private List<Pojo> mPojoList;

//...

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (item.getItemId() == R.id.the_id_for_my_menuitem) {
        if (booleanCheck() && !mPojoList.isEmpty()) {

            //create the Accessibility event
            final AccessibilityEvent event = AccessibilityEvent.obtain(AccessibilityEvent.TYPE_VIEW_CLICKED);
            event.setContentDescription(String.format("deleting %2d pojos", mPojoList.size()));

            //Send a custom accessibility event to let the user know that we're deleting X objects.
            final AccessibilityManager mgr = (AccessibilityManager) this.getActivity().getSystemService(Context.ACCESSIBILITY_SERVICE);

            //PROBLEM: We're not seeing this event come through in TalkBack.
            mgr.sendAccessibilityEvent(event);

            //Delete the objects.
            myDeleteObjectsFunction();
        }
    }
}}

Answer 1

虽然这是一个老问题，但我将公布我的答案，因为之前给出的答案对我不起作用。

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (item.getItemId() == R.id.the_id_for_my_menuitem) {
        if (booleanCheck() && !mPojoList.isEmpty()) {

            AccessibilityManager manager = (AccessibilityManager)this.getSystemService(Context.ACCESSIBILITY_SERVICE);
            if(manager.isEnabled()){
                AccessibilityEvent event = AccessibilityEvent.obtain();
                event.setEventType(AccessibilityEvent.TYPE_ANNOUNCEMENT);
                event.setClassName(getClass().getName());
                event.getText().add(*yourString*);

                if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
                    event.setSource(findViewById(*yourButton*));
                }
                manager.sendAccessibilityEvent(event);
            }
        }
    }
}

Answer 2

尝试使用 View 对象触发辅助功能事件。

AccessibilityEvent event = AccessibilityEvent.obtain(AccessibilityEvent.TYPE_VIEW_CLICKED);
event.setContentDescription(String.format("deleting %2d pojos", mPojoList.size()));

View view = getActivity().findViewById(R.id.child_view);

ViewParent parent = view.getParent();
if (parent != null) {
  parent.requestSendAccessibilityEvent(view, event);
}