@Override public void onTextChanged(CharSequence s, int start, int before, int count) { String bankId = ""; for (int i = 0; i < s.length(); i++) { if ((i + 1) % 4 == 0) { bankId += " "; } bankId += s.charAt(i); } bankcardnum.setText(bankId); Log.v( "TextWatcher-onTextChanged-->", " text=" + s.toString() + " length=" + s.length() + " start=" + start + " before-" + before + " count=" + count); }