Emoji表情编码: https://apps.timwhitlock.info/emoji/tables/unicode
基本过滤了所有,包括国旗神马的

public class EmojiFilter implements InputFilter {
    @Override
    public CharSequence filter(CharSequence source, int start, int end,
                               Spanned dest, int dstart, int dend) {
        StringBuffer buffer = new StringBuffer();
        for (int i = start; i < end; i++) {
            char codePoint = source.charAt(i);
            if (!getIsEmoji(codePoint)) {
                buffer.append(codePoint);
            } else {
                i++;
            }
        }
        if (source instanceof Spanned) {
            SpannableString sp = new SpannableString(buffer);
            TextUtils.copySpansFrom((Spanned) source, start, end, null,
                    sp, 0);
            return sp;
        } else {
            return buffer;
        }
    }

    public boolean getIsEmoji(char codePoint) {
        if ((codePoint == 0x0) || (codePoint == 0x9) || (codePoint == 0xA)
                || (codePoint == 0xD)
                || ((codePoint >= 0x20) && (codePoint <= 0x29))
                || ((codePoint >= 0x2A) && (codePoint <= 0x3A))
                || ((codePoint >= 0x40) && (codePoint <= 0xA8))
                || ((codePoint >= 0xAF) && (codePoint <= 0x203B))
                || ((codePoint >= 0x203D) && (codePoint <= 0x2048))
                || ((codePoint >= 0x2050) && (codePoint <= 0x20e2))
                || ((codePoint >= 0x20e4) && (codePoint <= 0x2100))
                || ((codePoint >= 0x21AF) && (codePoint <= 0x2300))
                || ((codePoint >= 0x23FF) && (codePoint <= 0X24C1))
                || ((codePoint >= 0X24C3) && (codePoint <= 0x2500))
                || ((codePoint >= 0x2800) && (codePoint <= 0x2933))
                || ((codePoint >= 0x2936) && (codePoint <= 0x2AFF))
                || ((codePoint >= 0x2C00) && (codePoint <= 0x3029))
                || ((codePoint >= 0x3031) && (codePoint <= 0x303C))
                || ((codePoint >= 0x303E) && (codePoint <= 0x3296))
                || ((codePoint >= 0x32A0) && (codePoint <= 0xD7FF))
                || ((codePoint >= 0xE000) && (codePoint <= 0xFE0E))
                || ((codePoint >= 0xFE10) && (codePoint <= 0xFFFD))
                || ((codePoint >= 0x10000) && (codePoint <= 0x10FFFF))) {
            return false;
        }
        return true;
    }
}

使用:

editText.setFilters(new InputFilter[]{new EmojiFilter()});