限制Android EditText中的小数位数

这是一个示例InputFilter，它仅允许在小数点前最多4位，在小数点后最多1位。

价值观是允许的EditText：555.2，555，0.2

价值观是的EditText块：55555.2，055.2，555.42

        InputFilter filter = new InputFilter() {        final int maxDigitsBeforeDecimalPoint=4;        final int maxDigitsAfterDecimalPoint=1;        @Override        public CharSequence filter(CharSequence source, int start, int end,     Spanned dest, int dstart, int dend) {     StringBuilder builder = new StringBuilder(dest);     builder.replace(dstart, dend, source  .subSequence(start, end).toString());     if (!builder.toString().matches(  "(([1-9]{1})([0-9]{0,"+(maxDigitsBeforeDecimalPoint-1)+"})?)?(\.[0-9]{0,"+maxDigitsAfterDecimalPoint+"})?"  )) {         if(source.length()==0)  return dest.subSequence(dstart, dend);         return "";     } return null;        }    };    mEdittext.setFilters(new InputFilter[] { filter });