android中EditText过滤Emoji表情

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Emoji表情编码

有关Emoji的表情编码参见Wikipedia
Emoji -Wikipedia

判断是否含有emoji表情

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/**
    * @param CharSequence source
    * 判断是否含有emoji表情
    */
   public static boolean isHasEmoji(CharSequence source) {
       Pattern emoji = Pattern.compile("[\ud83c\udc00-\ud83c\udfff]|[\ud83d\udc00-\ud83d\udfff]|[\u2600-\u27ff]", Pattern.UNICODE_CASE | Pattern.CASE_INSENSITIVE);
       Matcher emojiMatcher = emoji.matcher(source);
       if (emojiMatcher.find()) {
           return true;
       }
       return false;
   }

新建一个InputFilter 过滤emoji表情和限制字符串长度

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/**
 * This filter will constrain edits not to make the length of the text
 * greater than the specified length.Restrict input expression.
 */
public static class LengthAndEmoijFilter implements InputFilter {
    public LengthAndEmoijFilter(int max) {
        mMax = max;
    }
    public CharSequence filter(CharSequence source, int start, int end,
                               Spanned dest, int dstart, int dend) {
        //判断是否含有emoji表情
        if (isHasEmoji(source)) {
            return "";
        }
        int keep = mMax - (dest.length() - (dend - dstart));
        if (keep <= 0) {
            return "";
        } else if (keep >= end - start) {
            return null; // keep original
        } else {
            keep += start;
            if (Character.isHighSurrogate(source.charAt(keep - 1))) {
                --keep;
                if (keep == start) {
                    return "";
                }
            }
            return source.subSequence(start, keep);
        }
    }
    private int mMax;
}

在mEditText中设置过滤规则

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private static int MAX_MESSAGE_LENGTH = 10;//规定长度大小限制为10
mEditText.setFilters(new InputFilter[]{ new UPUtils.LengthAndEmoijFilter(MAX_MESSAGE_LENGTH) });