EditText selection on focus not working

Question

Since I am very disappointed in a way that Android is doing decimal input I decided to write my own EditDecimal control that inherits from EditText. I want it to select all on click and to put cursor on first position on focus. I don't want cursor to show because it's usless on most Android phones (you mostly cannot put it in right place and it makes me very nervous)

Problem is when you tap on control - FocusChanged is called but it does not set position of (hidden) cursor on first position but on position where user tapped. I can not find the problem... is there some other event that happens after FocusChange that moves cursor?

public class EditDecimal : EditText
{
    // Every constructor is calling Initialize ...

    private void Initialize()
    {

        FocusChange += OnFocusChanged;
        Click += OnClicked;
        SetCursorVisible(false);
    }

    private void OnFocusChanged(object sender, FocusChangeEventArgs e)
    {
        if (IsFocused)
            SetSelection(1);
    }

    private void OnClicked(object sender, EventArgs e)
    {
        SelectAll();
    }
}

Answer 1

I finnaly solved it. I had to subscribe to OnTouch event and to change cursor position from there.

public class EditDecimal : EditText
{
    // Every constructor is calling Initialize ...

    private InputMethodManager _imm ;
    public int DecimalSpaces { get; set; }
    readonly DecimalFormatSymbols _dfs = new DecimalFormatSymbols(); 

    private void Initialize(Context context, IAttributeSet attrs)
    {
        AfterTextChanged += OnAfterTextChanged; 
        SetSelectAllOnFocus(true);
        SetCursorVisible(false);            
        Touch += OnTouch;

        _imm = (InputMethodManager)context.GetSystemService(Context.InputMethodService);

        var a = context.ObtainStyledAttributes(attrs, Resource.Styleable.EditDecimal);
        try
        {
            DecimalSpaces = a.GetInteger(Resource.Styleable.EditDecimal_decimalSpaces, 2);
        }
        finally
        {
            a.Recycle();
        }
    }

    private void OnTouch(object sender, TouchEventArgs e)
    {
        base.OnTouchEvent(e.Event);


        if (e.Event.Action == MotionEventActions.Up)
        {
            SelectAll();
        }
    }

    protected override void OnFocusChanged(bool gainFocus, FocusSearchDirection direction, Rect previouslyFocusedRect)
    {
        base.OnFocusChanged(gainFocus, direction, previouslyFocusedRect);
        SelectAll();
    }

    private void OnAfterTextChanged(object sender, AfterTextChangedEventArgs e)
    {
        const char ch1 = '.';
        const char ch2 = ',';

        switch (_dfs.DecimalSeparator)
        {
            case ch2:
            {
                if (Text.Contains(ch1.ToString()))
                {
                    var position = Text.IndexOf(ch1);

                    if (Text.Contains(ch2.ToString()))
                        e.Editable.Delete(position, position + 1);
                    else
                        e.Editable.Replace(position, position + 1, ch2.ToString()); 
                }

                // we have to prevent showing two commas in number 
                var firstCommaPosition = Text.IndexOf(ch2);
                var lastCommaPosition = Text.LastIndexOf(ch2);

                if (firstCommaPosition > 0 && lastCommaPosition > 0 && firstCommaPosition != lastCommaPosition)
                    e.Editable.Delete(lastCommaPosition, lastCommaPosition+1);
            }
                break;
            case ch1:
            {
                if (Text.Contains(ch2.ToString()))
                {
                    var position = Text.IndexOf(ch2);
                    e.Editable.Delete(position, position + 1);
                }

                // we have to prevent showing two points in number 
                var firstPointPosition = Text.IndexOf(ch1);
                var lastPointPosition = Text.LastIndexOf(ch1);

                if (firstPointPosition > 0 && lastPointPosition > 0 && firstPointPosition != lastPointPosition)
                    e.Editable.Delete(lastPointPosition, lastPointPosition + 1);
            }
                break;
        }


        //thnx to http://stackoverflow.com/users/2240673/tom
        var length = e.Editable.Length();

        if (length <= 0) return;

        if (NrOfDecimal(e.Editable.ToString()) > DecimalSpaces)
            e.Editable.Delete(length - 1, length);
    }

    private int NrOfDecimal(string nr)
    {
        if (nr == null) return 0;

        var nrCharArray = nr.ToCharArray();

        var len = nr.Length;
        var pos = len;
        for (var i = 0; i < len; i++)
        {
            if (nrCharArray[i] != '.') continue;

            pos = i + 1;
            break;
        }
        return len - pos;
    }
}

What came as suprize to me was a fact that EditText selection behaves differently if SetCursorVisible is set to true than when it is set to false. I thought that it was just visibility property.

Answer 2

Grepcode is your friend. It shows that TextView's onFocusChanged method checks if there's an Editor object defined for the View (which is the case with EditText) and a look at the Editor code shows this at line 889 ff:

// If a tap was used to give focus to that view, move cursor at tap position.
// Has to be done before onTakeFocus, which can be overloaded.
final int lastTapPosition = getLastTapPosition();
if (lastTapPosition >= 0) {
    Selection.setSelection((Spannable) mTextView.getText(), lastTapPosition);
}

So perhaps the best way would be to write your own implementation of Editor. Although if have no idea right now how you attach that to your TextView resp. EditText. class.

Or you just set the selection back to the first position if that is what you want.