国际惯例，先上效果图

Github代码地址

环信SDK开发文档

部分代码

Application中初始化：

        var options = EMOptions()
        // 默认添加好友时，是不需要验证的，改成需要验证
        options.acceptInvitationAlways = false
        // 是否自动将消息附件上传到环信服务器，默认为True是使用环信服务器上传下载，如果设为 false，需要开发者自己处理附件消息的上传和下载
        options.autoTransferMessageAttachments = true
        // 是否自动下载附件类消息的缩略图等，默认为 true 这里和上边这个参数相关联
        options.setAutoDownloadThumbnail(true)
        //初始化
        EMClient.getInstance().init(applicationContext, options)
        //在做打包混淆时，关闭debug模式，避免消耗不必要的资源
        EMClient.getInstance().setDebugMode(true)

链接状态监听listener ：

open class ConnectionListener : EMConnectionListener {

    override fun onConnected() {
        Log.i("minfo", "账号连接成功")
    }

    override fun onDisconnected(errorCode: Int) {
        when(errorCode) {
            EMError.USER_REMOVED ->
                Log.i("minfo", "用户已被删除")
            EMError.USER_LOGIN_ANOTHER_DEVICE ->
                Log.i("minfo", "异地登录被挤掉")

        }
    }

}

账号注册：

        //注意：这里的注册有个坑，必须要在子线程中才可以，否则会抛出异常
        Thread {
            kotlin.run {
                //注册账号,注册失败会抛出HyphenateException: Registration failed.
                //比如重复注册，比如在子线程中注册
                try {
                    EMClient.getInstance().createAccount(userId, psd)  //同步方法
                } catch (e: Exception) {
                    Log.i("minfo", "账号已存在")
                }

                runOnUiThread {
                    //账号登录
                    login()
                }
            }
        }.start()

登录：

        EMClient.getInstance().login(userId, userPsd, object: EMCallBack {
            override fun onSuccess() {
                Log.i("minfo", "登录聊天服务器成功")
                startActivity(Intent(this@LoginActivity, MainActivity::class.java))
            }

            override fun onProgress(progress: Int, status: String?) {

            }

            override fun onError(code: Int, error: String?) {
                Log.i("minfo", "登录聊天服务器失败")
            }

        })

退出登录：

        EMClient.getInstance().logout(true, object: EMCallBack {
            override fun onSuccess() {
                Log.i("minfo", "退出登录成功")
            }

            override fun onProgress(progress: Int, status: String?) {

            }

            override fun onError(code: Int, error: String?) {
                Log.i("minfo", "退出登录失败")
            }

        })

EaseUI 使用指南

EaseUI 是一个 UI 库，封装了 IM 功能常用的控件、fragment 等等，旨在帮助开发者快速集成环信 SDK。

- 会话列表页面：EaseConversationListFragment

conversationListFragment = new EaseConversationListFragment();
conversationListFragment.setConversationListItemClickListener(new EaseConversationListItemClickListener() {
            
    @Override
    public void onListItemClicked(EMConversation conversation) {
        startActivity(new Intent(MainActivity.this, ChatActivity.class).putExtra(EaseConstant.EXTRA_USER_ID, conversation.getUserName()));
    }
});

- 联系人列表EaseContactListFragment

contactListFragment= new EaseContactListFragment();
//需要设置联系人列表才能启动fragment
contactListFragment.setContactsMap(getContacts());
//设置item点击事件
contactListFragment.setContactListItemClickListener(new EaseContactListItemClickListener() {
            
            @Override
            public void onListItemClicked(EaseUser user) {
                startActivity(new Intent(MainActivity.this, ChatActivity.class).putExtra(EaseConstant.EXTRA_USER_ID, user.getUsername()));
            }
        });

- 聊天页面：EaseChatFragment

        val chatFragment = EaseChatFragment()
        val args = Bundle()
        args.putInt(EaseConstant.EXTRA_CHAT_TYPE, EaseConstant.CHATTYPE_SINGLE)
        args.putString(EaseConstant.EXTRA_USER_ID, userId)
        chatFragment.arguments = args
        supportFragmentManager.beginTransaction().add(R.id.flChat, chatFragment).commit()