How do I format a string into EditText in Android with "AAA-AAA-AAA" format

I need to get an input of 9 uppercase letters separated by dash like AAA-AAA-AAA and this input has to be formatted while is entered.

Thanks in advance.

I have found the solution using a TextWatcher. I'm using

android:inputType="textCapCharacters|textNoSuggestions"

for the EditText input type in order to receive only uppercase letters.

        txtCode = (EditText) findViewById(R.id.txtCode);

        txtCode.addTextChangedListener( new TextWatcher() {
            boolean isEdiging;
            @Override 
            public void onTextChanged(CharSequence s, int start, int before, int count) { }
            @Override 
            public void beforeTextChanged(CharSequence s, int start, int count, int after) { }


            @Override
            public void afterTextChanged(Editable s) {
                if(isEdiging) return;
                isEdiging = true;
                // removing old dashes
                StringBuilder sb = new StringBuilder();
                sb.append(s.toString().replace("-", ""));

                if (sb.length()> 3)
                    sb.insert(3, "-");
                if (sb.length()> 7)
                    sb.insert(7, "-");
                if(sb.length()> 11)
                    sb.delete(11, sb.length());

                s.replace(0, s.length(), sb.toString());
                isEdiging = false;
            }
        });