Android 使用 setAccessibilityTraversalAfter() 更改可访问性顺序不起作用

Question

What I want is to change the accessibility order, the order in which the screen reader, the TalkBack in that Android case, read the elements, after pressing a button. This is what I tried by far, but it doesn't work, the order is still the initial descending ones. (In my example buttons are in order b1, b2, b3, and after I presso button changeorder I want the order to become b3,b1,b2).

CODE:

   Button b1,b2,b3, changeorder;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    LinearLayout linearlayout = findViewById(R.id.linearlayout);

    changeorder = new Button(this);
    changeorder.setText("Presso to change order");
    changeorder.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Log.i("BUTTON","Clicked change order button");

            changeorder.setAccessibilityTraversalBefore(b3.getId());
            b3.setAccessibilityTraversalAfter(changeorder.getId());
            b3.setAccessibilityTraversalBefore(b1.getId());
            b1.setAccessibilityTraversalAfter(b3.getId());
            b1.setAccessibilityTraversalBefore(b2.getId());
            b2.setAccessibilityTraversalAfter(b1.getId());
            changeorder.setText("Order changed b3,b1,b2");

        }
    });
    changeorder.setImportantForAccessibility(View.IMPORTANT_FOR_ACCESSIBILITY_YES);
    linearlayout.addView(changeorder);

    b1 = new Button(this);
    b1.setText("BUTTON 1");
    b1.setImportantForAccessibility(View.IMPORTANT_FOR_ACCESSIBILITY_YES);
    linearlayout.addView(b1);


    b2 = new Button(this);
    b2.setText("BUTTON 2");
    b2.setImportantForAccessibility(View.IMPORTANT_FOR_ACCESSIBILITY_YES);
    linearlayout.addView(b2);


    b3 = new Button(this);
    b3.setText("BUTTON 3");
    b3.setImportantForAccessibility(View.IMPORTANT_FOR_ACCESSIBILITY_YES);
    linearlayout.addView(b3);


    }

Answer 1

Your Button s don't have IDs, so when you call getId() in b3.setAccessibilityTraversalBefore(b1.getId()); , etc., you're gettingView.NO_ID , so the traversal order isn't being set up correctly.

To fix it, define some IDs in XML :

<resources>
    <item type="id" name="changeOrderButton" />
    <item type="id" name="button1" />
    <item type="id" name="button2" />
    <item type="id" name="button3" />
</resources>

and then set them on your buttons with View.setId when you create them:

b1 = new Button(this);
b1.setId(R.id.button1); // Add the ID so that accessibility traversal can identify this view
b1.setText("BUTTON 1");
b1.setImportantForAccessibility(View.IMPORTANT_FOR_ACCESSIBILITY_YES);
linearlayout.addView(b1);

(and do the same for the rest of the buttons)

Answer 2

This was too long for a comment, not an 'answer' as such.

Don't try and change the traversal order on an active element (which the button will be when you press it).

ie remove the changeorder.setAccessibilityTraversalBefore(b3.getId()); bit.

Also bear in mind that you only need to use one version of setAccessibilityTraversal as
b3.setAccessibilityTraversalBefore(b1.getId()); is the same as b1.setAccessibilityTraversalAfter(b3.getId());

so simplified it would be:-

public void onClick(View v) {
        Log.i("BUTTON","Clicked change order button");

    b3.setAccessibilityTraversalAfter(changeorder.getId());
    b1.setAccessibilityTraversalAfter(b3.getId());
    b2.setAccessibilityTraversalAfter(b1.getId());
    changeorder.setText("Order changed b3,b1,b2");
    etc.