Cyclical replacement the content of EditText with the limited length

Question

For example, I have EditText with length limitation of two characters. When the first and second letters entered it's ok. But when we will try to enter a third letter the first letter should be replaced with it. Next letter should replace the second and so on in a circle. How can I do this one.

Answer 1

Try using TextWatcher on your edit text to achieve the goal

editText.addTextChangedListener(new TextWatcher() {

        private int lastModifiedIndex = 1;

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

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            if (s.length() > 2) {
                char toReplace = s.charAt(s.length() - 1);
                if (lastModifiedIndex == 0) {
                    editText.setText("" + s.charAt(lastModifiedIndex) + toReplace);
                    lastModifiedIndex = 1;
                    editText.setSelection(s.length());
                } else {
                    editText.setText("" + toReplace + s.charAt(lastModifiedIndex));
                    lastModifiedIndex = 0;
                    editText.setSelection(s.length());
                }
            } else {
                lastModifiedIndex = 1;
            }
        }

        @Override
        public void afterTextChanged(Editable s) {

        }
    });