##RichEditor 类似新浪微博EditText，可@某人，#插入话题，表情。

###实现思路

1. 在光标处插入特殊字符

    //将特殊字符插入到EditText 中显示
    int index = getSelectionStart();//光标位置
    Editable editable = getText();//原先内容
    SpannableStringBuilder spannableStringBuilder = new SpannableStringBuilder(editable);
    Spanned htmlText = Html.fromHtml(String.format(String.format("<font color='%s'>" + insertContent + "</font>", insertColor)));
    spannableStringBuilder.insert(index, htmlText);
    spannableStringBuilder.insert(index + htmlText.length(), "\b");
    setText(spannableStringBuilder);
    setSelection(index + htmlText.length() + 1);
   

2. 实现特殊字符选中删除效果

    /**
     * 监听删除键 <br/>
     * 1.光标在话题后面,将整个话题内容删除 <br/>
     * 2.光标在普通文字后面,删除一个字符
     *
     */
    this.setOnKeyListener(new View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (keyCode == KeyEvent.KEYCODE_DEL && event.getAction() == KeyEvent.ACTION_DOWN) {
   
                int selectionStart = getSelectionStart();
                int selectionEnd = getSelectionEnd();
   
                /**
                 * 如果光标起始和结束不在同一位置,删除文本
                 */
                if (selectionStart != selectionEnd) {
                    // 查询文本是否属于目标对象,若是移除列表数据
                    String tagetText = getText().toString().substring(
                            selectionStart, selectionEnd);
                    for (int i = 0; i < insertModelList.size(); i++) {
                        InsertModel object = insertModelList.get(i);
                        if (tagetText.equals(object.getInsertContent())) {
                            insertModelList.remove(object);
                        }
                    }
                    return false;
                }
   
   
                int lastPos = 0;
                Editable editable = getText();
                // 遍历判断光标的位置
                for (int i = 0; i < insertModelList.size(); i++) {
                    String objectText = insertModelList.get(i).getInsertContent();
                    lastPos = getText().toString().indexOf(objectText, lastPos);
                    if (lastPos != -1) {
                        if (selectionStart != 0 && selectionStart >= lastPos && selectionStart <= (lastPos + objectText.length())) {
                            // 选中话题
                            setSelection(lastPos, lastPos + objectText.length());
                            // 设置背景色
                            editable.setSpan(new BackgroundColorSpan(BACKGROUND_COLOR), lastPos, lastPos + objectText.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
                            return true;
                        }
                    }
                    lastPos += objectText.length();
                }
            }
   
            return false;
        }
    });
   

3. 设置点击特殊字符光标自动移动到特殊字符之后

    /**
     * 监听光标的位置,若光标处于话题内容中间则移动光标到话题结束位置
     *
     */
    @Override
    protected void onSelectionChanged(int selStart, int selEnd) {
    super.onSelectionChanged(selStart, selEnd);
    if (insertModelList == null || insertModelList.size() == 0)
        return;
    int startPostion = 0;
    int endPostion = 0;
    String insertContent = "";
    for (int i = 0; i < insertModelList.size(); i++) {
        insertContent = insertModelList.get(i).getInsertContent();
        startPostion = getText().toString().indexOf(insertContent);
        endPostion = startPostion + insertContent.length();
        if (startPostion != -1 && selStart > startPostion
                && selStart <= endPostion) {// 若光标处于话题内容中间则移动光标到话题结束位置
            setSelection(endPostion);
        }
    }}