android 的短信实现方式普通用户适应的话需要长时间的使用才能习惯，将andorid的短信模式设置成我们常用的（一般人用户）的习惯。在查看字符转图片的过程中可以猜测出腾讯的QQ表情的原理应该是一样的
只是在传送非常用的表情时是将byte数据转换为image.
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/***
???? *
???????? * 此方法描述的是：?? 注意此方法在做表情转换的准备了
???????? * @author:[email protected],[email protected]
???????? * @version: 2010-5-13 下午03:31:13
???? */
??? private void bindCommonMessage(final MessageItem msgItem) {
??????? if (mDownloadButton != null) {
??????????? mDownloadButton.setVisibility(View.GONE);
??????????? mDownloadingLabel.setVisibility(View.GONE);
??????? }
??????? // Since the message text should be concatenated with the sender's
??????? // address(or name), I have to display it here instead of
??????? // displaying it by the Presenter.
??????? mBodyTextView.setTransformationMethod(HideReturnsTransformationMethod.getInstance());
??????? // Get and/or lazily set the formatted message from/on the
??????? // MessageItem. Because the MessageItem instances come from a
??????? // cache (currently of size ~50), the hit rate on avoiding the
??????? // expensive formatMessage() call is very high.
??????? CharSequence formattedMessage = msgItem.getCachedFormattedMessage();
??????? if (formattedMessage == null) { //肯定为null应为msgItem.formattedMessage从诞生来就没被注意过一次
??????????? formattedMessage = formatMessage(msgItem.mContact, msgItem.mBody,?? //重点到了
???????????????????????????????????????????? msgItem.mSubject, msgItem.mTimestamp,
???????????????????????????????????????????? msgItem.mHighlight);
??????????? msgItem.setCachedFormattedMessage(formattedMessage);
??????? }
??????? mBodyTextView.setText(formattedMessage);
??????? if (msgItem.isSms()) {
??????????? hideMmsViewIfNeeded();
??????? } else {
??????????? Presenter presenter = PresenterFactory.getPresenter(
??????????????????? "MmsThumbnailPresenter", mContext,
??????????????????? this, msgItem.mSlideshow);
??????????? presenter.present();
??????????? if (msgItem.mAttachmentType != WorkingMessage.TEXT) {
??????????????? inflateMmsView();
??????????????? mMmsView.setVisibility(View.VISIBLE);
??????????????? setOnClickListener(msgItem);
??????????????? drawPlaybackButton(msgItem);
??????????? } else {
??????????????? hideMmsViewIfNeeded();
??????????? }
??????? }
??????? drawLeftStatusIndicator(msgItem.mBoxId);
??????? drawRightStatusIndicator(msgItem);
??? }
//------------------------------------------
/***
???? *
???????? * 此方法描述的是：?? 开始转换了哦
???????? * @author:[email protected],[email protected]
???????? * @version: 2010-5-13 下午03:32:52
???? */
??? private CharSequence formatMessage(String contact, String body, String subject,
?????????????????????????????????????? String timestamp, String highlight) {
??????? CharSequence template = mContext.getResources().getText(R.string.name_colon); //遇到鬼了???? <主题：<xliff:g id="SUBJECT">%s</xliff:g>>"
??????? SpannableStringBuilder buf = ????????????????? //把他当作StringBuffer只是它可以放的不是 String 而已他能放跟多类型的东西
??????????? new SpannableStringBuilder(TextUtils.replace(template,
??????????????? new String[] { "%s" },
??????????????? new CharSequence[] { contact })); //替换成联系人
??????? boolean hasSubject = !TextUtils.isEmpty(subject); //主题
??????? if (hasSubject) {
??????????? buf.append(mContext.getResources().getString(R.string.inline_subject, subject)); //buff先在是 联系人 主题 XXXX????? eg wuyi <主题:dsadasdsa> 我爱我家
??????? }
??????? if (!TextUtils.isEmpty(body)) {
??????????? if (hasSubject) {
??????????????? buf.append(" - "); //如果内容有主题有就+ " - "??? eg wuyi <主题:sdsadsadsa> -
??????????? }
??????????? SmileyParser parser = SmileyParser.getInstance(); //获得表情类了哦
??????????? buf.append(parser.addSmileySpans(body)); //追查 急切关注中
??????? }
??????? if (!TextUtils.isEmpty(timestamp)) {
??????????? buf.append("\n");
??????????? int startOffset = buf.length();
??????????? // put a one pixel high spacer line between the message and the time stamp as requested
??????????? // by the spec.
??????????? //把之间的信息和时间戳的要求间隔一个像素的高线
??????????? //由规范
??????????? buf.append("\n");
??????????? buf.setSpan(new AbsoluteSizeSpan(3), startOffset, buf.length(),
??????????????????? Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
??????????? startOffset = buf.length();
??????????? buf.append(timestamp);
??????????? buf.setSpan(new AbsoluteSizeSpan(12), startOffset, buf.length(),
??????????????????? Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
??????????? // Make the timestamp text not as dark 改变某区域颜色?? 时间的地方为特殊颜色
??????????? int color = mContext.getResources().getColor(R.color.timestamp_color);
??????????? buf.setSpan(new ForegroundColorSpan(color), startOffset, buf.length(),
??????????????????? Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
??????? }
??????? if (highlight != null) {
??????????? int highlightLen = highlight.length();
??????????? String s = buf.toString().toLowerCase();
??????????? int prev = 0;
??????????? while (true) {
??????????????? int index = s.indexOf(highlight, prev);
??????????????? if (index == -1) {
??????????????????? break;
??????????????? }
??????????????? buf.setSpan(new StyleSpan(Typeface.BOLD), index, index + highlightLen, 0);
??????????????? prev = index + highlightLen;
??????????? }
??????? }
??????? return buf;
??? }
//------------------------
/**
???? * Adds ImageSpans to a CharSequence that replace textual emoticons such
???? * as :-) with a graphical version.
???? *
???? * @param text A CharSequence possibly containing emoticons
???? * @return A CharSequence annotated with ImageSpans covering any
???? *???????? recognized emoticons.
???? * 添加ImageSpans一个CharSequence的表情符号代替文字等???? *如用图形版本:-)。
???? * 核心是把表情字符替换成ImageSpans的对象
???? */
??? public CharSequence addSmileySpans(CharSequence text) {
??????? SpannableStringBuilder builder = new SpannableStringBuilder(text);
??????? Matcher matcher = mPattern.matcher(text);
??????? while (matcher.find()) {
??????????? int resId = mSmileyToRes.get(matcher.group());
??????????? //注意下面的一块有点不好理解哦但是是核心
??????????? builder.setSpan(new ImageSpan(mContext, resId), matcher.start(), matcher.end(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
??????? }
??????? return builder;
??? }
总结：
???? android 在将字符转化为表情图像其核心代码为
builder.setSpan(new ImageSpan(mContext, resId), matcher.start(), matcher.end(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
原理过程是先匹配到表情字符然后通过new ImageSpan(上下文,表情地址)绘制出一个ImageView然后替换掉表情字符。
?