EmojiInputFilter EditText用InputFilter将文字替换成表情

核心代码

/**
 * 表情过滤器
 *
 * @author gavin.xiong 2016/12/21
 */
public class EmojiInputFilter implements InputFilter {

    private Context context;

    private String[] faceImages;
    private String[] faceScr;

    private final String regex;
    private final Pattern pattern;

    private int emojiDpSize;

    private ArrayMap faceBook;

    public EmojiInputFilter(Context context) {
        this.context = context;
        faceImages = context.getResources().getStringArray(R.array.emoji);
        faceScr = context.getResources().getStringArray(R.array.emoji_desc);

        regex = buildRegex();
        pattern = Pattern.compile(regex);
        faceBook = buildEmojiToRes();
        
        float scale = Resources.getSystem().getDisplayMetrics().density;
        emojiDpSize = (int) (20 * scale + 0.5f);
    }

    @Override
    public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
        if (end > start) source = source.subSequence(start, end);

        // 新输入的字符串为空（删除剪切等）
        if (TextUtils.isEmpty(source)) return null;

        return source.toString().matches(".*" + regex + ".*") ? addEmojiSpans(source) : null;
    }

    private CharSequence addEmojiSpans(CharSequence text) {
        SpannableStringBuilder builder = new SpannableStringBuilder(text);
        Matcher matcher = pattern.matcher(text);
        while (matcher.find()) {
            int resId = faceBook.get(matcher.group());
            Drawable dr = ContextCompat.getDrawable(context, resId);
            dr.setBounds(0, 0, emojiDpSize, emojiDpSize);
            builder.setSpan(new ImageSpan(dr, ImageSpan.ALIGN_BOTTOM), matcher.start(), matcher.end(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        }
        return builder;
    }

    private String buildRegex() {
        StringBuilder regex = new StringBuilder(faceScr.length * 3);
        regex.append('(');
        for (String s : faceScr) {
            regex.append(Pattern.quote(s)).append('|');
        }
        regex.replace(regex.length() - 1, regex.length(), ")");
        return regex.toString();
    }

    private ArrayMap buildEmojiToRes() {
        if (faceImages.length != faceScr.length) {
            throw new IllegalStateException("Emoji resource ID/text mismatch");
        }
        ArrayMap smileyToRes = new ArrayMap<>(faceScr.length);
        String packageName = context.getPackageName();
        for (int i = 0; i < faceScr.length; i++) {
            int resId = context.getResources().getIdentifier(faceImages[i], "drawable", packageName);
            smileyToRes.put(faceScr[i], resId);
        }
        return smileyToRes;
    }
}

使用

textView.setFilters(new InputFilter[]{new EmojiInputFilter(this)});
或
editText.setFilters(new InputFilter[]{new EmojiInputFilter(this)});

上图

微信图片_20170401155316.jpg

apk

app-debug.apk

完整代码已上传至github

https://github.com/gavinxxxxxx/EmojiInputFilter