Xamarin Android Accessibility - how can we set accessibility focus to a UI element like a button programatically

Question

In my Xamarin Android application user needs to select an item from a spinner (dropdown menu). After selecting any item from the spinner the accessibility focus shifts to the start of the screen instead of the next focusable element, which is not the expected behavior. So trying to find a way to set focus to the button programmatically but it seems there is no way in Xamarin Android.

I have tried

Button1.RequestFocus();

Button1.RequestFocusFromTouch();

Button1.SendAccessibilityEvent(EventTypes.ViewAccessibilityFocused);

But nothing works!!

The below code example is related to Xamarin iOS:

    UIAccessibility.PostNotification(UIAccessibilityPostNotification.ScreenChanged, myFirstElement);

This method which is available in Xamarin iOS works fine so need a similar way for Xamarin Android to focus programmatically.

Here, I am posting sample code.

My .axml file code:

<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <Spinner
        android:id="@+id/spinner"
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"   android:focusable="true"    android:focusableInTouchMode="true"/>
    <Button
        android:text="Add"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/btnAdd" 
        android:focusable="true"
        android:focusableInTouchMode="true"/>
</LinearLayout> </LinearLayout>

My Activity file

protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);

        // Set our view from the "main" layout resource
        this.SetContentView (Resource.Layout.Main);
Spinner spinner = this.FindViewById<Spinner>(Resource.Id.spinner);
        Button btnAdd = this.FindViewById<Button>(Resource.Id.btnAdd);
var adapter = ArrayAdapter.CreateFromResource(this, Resource.Array.planets_array, Android.Resource.Layout.SimpleSpinnerItem);

            adapter.SetDropDownViewResource(Android.Resource.Layout.SimpleSpinnerDropDownItem);
            spinner.Adapter = adapter;
            btnAdd.Click += (s, e) =>
              {
                  string toasts = string.Format("Add button got focus");
                  Toast.MakeText(this, toasts, ToastLength.Long).Show();
              };

        }

        private void spinner_ItemSelected(object sender, AdapterView.ItemSelectedEventArgs e)
        {
            Spinner spinner = (Spinner)sender;

            string toast = string.Format("The planet is {0}", spinner.GetItemAtPosition(e.Position));
            Toast.MakeText(this, toast, ToastLength.Long).Show();
            //btnAdd.RequestFocus();
            btnAdd.RequestFocusFromTouch();
            btnAdd.RequestFocus();
            if (btnAdd.IsFocused)
            {
                string toasts = string.Format("Add button got focus");
                Toast.MakeText(this, toasts, ToastLength.Long).Show();                
            }
            skillSeleted = "selected";
        }

        protected override void OnResume()
        {
            base.OnResume();
            if (skillSeleted == "selected")
            {
                btnAdd.RequestFocusFromTouch();
                btnAdd.RequestFocus();
            }
        }


//Add this to String file under values folder:
<string-array name="planets_array">
<item>Mercury</item>
<item>Venus</item>
<item>Earth</item>
<item>Mars</item>
<item>Jupiter</item>
<item>Saturn</item>
<item>Uranus</item>
<item>Neptune</item>

Please check this scenario in Samsung Mobile with Marshmallow android version.

Thanks in advance.

Possible duplicate of [How to set focus to a button widget programmatically?](http://stackoverflow.com/questions/3234607/how-to-set-focus-to-a-button-widget-programmatically) — SushiHangover, Jan 03 '17 at 15:27
for a normal button setting request focus method works but in this case, after an item is selected from spinner the focus is lost somehow so the focus goes to the start of the page. Requesting focus on item selected event also doesn't work. — Lavanya Rani, Jan 03 '17 at 18:33
Yes, i have set 'Focusable= true' and also 'FocusableInTouchMode=true' — Lavanya Rani, Jan 04 '17 at 05:17
You can going to have to post some reproducible AXML and code — SushiHangover, Jan 04 '17 at 07:17

score 0 · Answer 1 · edited Feb 14 '22 at 10:47

public class MainPage : ContentPage {
    public MainPage() => Content = BuildView().CreateView();

    void SetState() => BuildView().Apply(Content);

    int _counter;

    Command _push => new Command(() => {
        _counter++;
        SetState();
    });

    ViewModel BuildView() =>
        new StackLayoutModel(
            children: new ViewModel[] {
                new LabelModel(text: _counter.ToString(), fontSize: 42),
                new ButtonModel(text: "Increment", command: _push),
            },
            padding: new Thickness(42));
}

Xamarin Android Accessibility - how can we set accessibility focus to a UI element like a button programatically

1 Answers1