Android虚拟键盘事件

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

Maybe you can check if the field is empty before and after change? Don't know if any other key press can leave the field empty and so you can say, back was pressed and jump to previous field. Ok this is not a real technical solution, but just a different way of viewing the problem.

Answer 2

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