It is essential to handle leading zeros. https://stackoverflow.com/questions/33229792/regex-input-filter-for-android-to-prevent-more-than-one-leading-zero.

IntegerInputFilter.java

public class IntegerInputFilter implements InputFilter {

    private Pattern pattern = Pattern.compile("^(?!0{1,})\\d+(?:\\.\\d+)?$");
    //or ..{1,}..

    public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
        //Log.e("word "+source+ "  "+dest);
        Matcher matcher = pattern.matcher(dest.toString()+source.toString());
        //you can handle with length == 1 return null;
        if(!matcher.matches()){
            Log.e("leading zero");
            return "";
        }
        return null;
    }
}