Question

I’m trying to implement iPhone like PIN-code authorization with 4 EditText blocks like this:

I’m using TextWatcher to check if field was changed so I can jump between blocks.
Here is the code:

@Override
public void afterTextChanged(Editable s) {
    if (del && index > 0) {
        pin[index - 1].requestFocus();
    }
    else if ( ! del && ind < 3) {
        pin[index + 1].requestFocus();
    }
}

@Override
public void beforeTextChanged(CharSequence s, int start, int count,
        int after) {

    del = count != 0;
}

Everything works fine except when block is empty and DEL/BACKSPACE is pressed, I want to go back to previous block and clear its’ value.
This is where TextWatcher fails me since no change was made in empty block it doesn’t do anything.

I have tried using keyEventListener but it only catches events on emulator not on actual device via virtual keyboard.

Can anyone suggest an idea of how can I catch DEL event or any other way to implement this?

Answer 1

I found a workaround for this issue. This is probably not the best solution, but it works for me.
Aside from TextWatcher I’ve added InputFilter to blocks

@Override
public CharSequence filter(CharSequence source, int start, int end,
        Spanned dest, int dstart, int dend) {
    if ( end == 0 && ind > 0 && dest.length() == 0 ) {
        pin[ind - 1].requestFocus();
    }
    return null;
}

I also think it’s a better idea to port the rest of the code from TextWatcher to InputFilter