@Override
public void afterTextChanged(Editable editable) {

    if(editable.length() == LEFT_EDITOR_MAX_LENGTH && Character.isLetter(editable.charAt(LEFT_EDITOR_MAX_LENGTH - 1))){
            fragment.goToNextView();
        } else if(editable.length() > LEFT_EDITOR_MAX_LENGTH - 1){
        //if (editable.length() > LEFT_EDITOR_MAX_LENGTH + 1) {
            fragment.removeInvalidChar();
    }

}

protected void goToNextView() {
      if (edi1.hasFocus()) {
        edi1.removeTextChangedListener(watcher1);
        edi2.requestFocus();
    } else if (edi2.hasFocus()) {
        edi2.removeTextChangedListener(watcher2);
        edi3.requestFocus();
    } else if (edi3.hasFocus()) {
        edi3.removeTextChangedListener(watcher3);
        sendPassphrase();
    }
}

protected EditText getFocusedEditText() {
    if (edi1.hasFocus()) {
        return edi1;
    } else if (edi2.hasFocus()) {
        return edi2;
    } else {
        return edi3;
    }
}

void removeInvalidChar() {
    EditText focusedEditText = getFocusedEditText();

    updateEmptyTextField(focusedEditText, "");

}

private void updateEmptyTextField(EditText editText, String emptyString) {
    editText.setText(emptyString);
    editText.setSelection(editText.getText().length());
}