feat:更新消息通知功能

lib/models/im_message.dart

@@ -15,12 +15,14 @@ enum ImMessageType {
 
 class ImMessage {
   final ImMessageType type;
+  final String title;
   final String from;
   final String to;
   final String content;
 
   ImMessage({
     required this.type,
+    required this.title,
     required this.from,
     required this.to,
     required this.content,
@@ -33,6 +35,7 @@ class ImMessage {
   factory ImMessage.fromJson(Map<String, dynamic> json) {
     return ImMessage(
       type: ImMessageType.values.firstWhere((e) => e.value == json['type']),
+      title: json['title'],
       from: json['from'],
       to: json['to'],
       content: json['content'],
@@ -41,6 +44,7 @@ class ImMessage {
 
   Map<String, dynamic> toJson() => {
     'type': type.value,
+    'title': title,
     'from': from,
     'to': to,
     'content': content,
@@ -53,6 +57,7 @@ class ImMessage {
   static ImMessage online(int userId) {
     return ImMessage(
       type: ImMessageType.online,
+      title: '',
       from: userId.toString(),
       to: 'SYSTEM',
       content: '',