我在开发中发现没有消息置顶这个功能，然后我公司要求开发个消息置顶的功能，所以就的手动写了。环信好多功能都要自己写，消息撤回，文件夹等等

思路

我就想能不能在每个消息里面设置个标识，来区分是否是置顶的消息，然后我找了下消息实体类EMConversation。其中就有两个方法getExtField()和setExtField(“”)，反正我也不管这是什么方法发，反正我就能存能取就够了。哈哈。。。

主要方法

1、getExtField();
2、setExtField(“”)

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2017-06-30_152028.png

开始实战

1. 在你要添加的置顶方法，我的是ConversationListFragment类中setUpView()方法中定义的侧滑按钮

 //置顶消息
        EMConversation tobeDeleteCons = (EMConversation)conversationListView.getItemAtPosition(conversationListView.getPositionForView(view));
        String isTop = tobeDeleteCons.getExtField();
            //判断是否是置顶消息  
        if("toTop".equals(isTop)){
           //取消置顶，就设置为其他的字符串
            tobeDeleteCons.setExtField("false");
        }else {
            //把它设置为置顶的标识
            tobeDeleteCons.setExtField("toTop");
        }
        //刷新消息列表
        refresh();

2.找到数据源在添加消息前添加进列表中。我的是EaseConversationListFragment中setUpView()方法，

 conversationList.addAll(loadConversationList());
        conversationListView.init(conversationList);

这个是主要方法

 /**
     * load conversation list
     * 
     * @return
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        +    */
    protected List<EMConversation> loadConversationList(){
        // get all conversations
        Map<String, EMConversation> conversations = EMClient.getInstance().chatManager().getAllConversations();
        onHandleEMConversation(conversations);

        //添加置顶消息
        List<Pair<Long, EMConversation>> topList = new ArrayList<Pair<Long, EMConversation>>();
        synchronized (conversations) {
            for (EMConversation conversation : conversations.values()) {
                if (conversation.getAllMessages().size() != 0 && conversation.getExtField().equals("toTop")) {
                    topList.add(new Pair<Long, EMConversation>(conversation.getLastMessage().getMsgTime(), conversation));
                }
            }
        }

        List<Pair<Long, EMConversation>> sortList = new ArrayList<Pair<Long, EMConversation>>();
        /**
         * lastMsgTime will change if there is new message during sorting
         * so use synchronized to make sure timestamp of last message won't change.
         */
        synchronized (conversations) {
            for (EMConversation conversation : conversations.values()) {
                if (conversation.getAllMessages().size() != 0 && !conversation.getExtField().equals("toTop")) {
                    sortList.add(new Pair<Long, EMConversation>(conversation.getLastMessage().getMsgTime(), conversation));
                }
            }
        }
        try {
            // Internal is TimSort algorithm, has bug
            sortConversationByLastChatTime(sortList);
        } catch (Exception e) {
            e.printStackTrace();
        }
        List<EMConversation> list = new ArrayList<EMConversation>();
        //添加置顶消息
        for (Pair<Long, EMConversation> topItem : topList) {
            list.add(topItem.second);
        }

        for (Pair<Long, EMConversation> sortItem : sortList) {
            list.add(sortItem.second);
        }
        return list;
    }

3.在EaseConversationAdapter中加上一些信息

 EMConversation conversation = getItem(position);
        //判断是否置顶，置顶改变文字
        String isTop = conversation.getExtField();
        if("toTop".equals(isTop)){
            holder.btnToTop.setText("取消置顶");
            holder.list_itease_layout.setBackgroundResource(R.drawable.ease_mm_top_listitem);
        }else {
            holder.btnToTop.setText("置顶");
            holder.list_itease_layout.setBackgroundResource(R.drawable.ease_mm_listitem);
        }

到此就改造好了