限制EditText输入小数的Filter

使用正则表达式，控制输入小数点：

public DecimalDigitsInputFilter(int digitsBeforeZero, int digitsAfterZero) {
        mPattern = Pattern.compile("([0-9]{1," + (digitsBeforeZero) + "})(\\.[0-9]{0," + digitsAfterZero + "})?");
    }
           

输入特殊符号和数字的处理：

@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());
        Matcher matcher = mPattern.matcher(builder.toString());
        if (!matcher.matches()) {
            return "";
        } else if ("0".equals(dest.toString())) {
            if (".".equals(source.toString())) {
                return null;
            } else if (dstart == 0 && !"0".equals(source.toString())) {
                return null;
            } else {
                return "";
            }
        } else if ("0".equals(source.toString())) {
            if (0 == dstart && dest.length() == 0) {
                return null;
            } else if (0 == dstart && dest.length() > 0) {
                return "";
            } else if (dstart > 0 && dest.length() > 0) {
                return null;
            }
        }

        return null;
    }