EditText txtInput = (EditText) findViewById(R.id.txtInput);
txtInput.addTextChangedListener(new TextWatcher() 
{
    public void afterTextChanged(Editable edt) 
    {
        String temp = edt.toString();
        int posDot = temp.indexOf(".");
        if (posDot <= 0) return;
        if (temp.length() - posDot - 1 > 2)
        {
            edt.delete(posDot + 3, posDot + 4);
        }
    }

    public void beforeTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {}

    public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {}
});
android:inputType="numberDecimal"