基础页面

lib/services/tim/message_service.dart

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+import 'package:get/get.dart';
+import 'package:scroll_to_index/scroll_to_index.dart';
+import 'package:tencent_im_sdk_plugin/enum/conversation_type.dart';
+import 'package:tencent_im_sdk_plugin/models/v2_tim_conversation.dart';
+import 'package:tencent_im_sdk_plugin/models/v2_tim_message.dart';
+import 'package:tencent_im_sdk_plugin/models/v2_tim_value_callback.dart';
+import 'conversation_service.dart';
+
+class LoadMessageResult {
+  String? lastMsgId;
+  bool noMore;
+
+  LoadMessageResult({
+    this.lastMsgId,
+    required this.noMore,
+  });
+}
+
+class TimMessageService extends GetxService {
+  static TimMessageService get to => Get.find<TimMessageService>();
+
+  RxList<V2TimMessage> messages = List<V2TimMessage>.empty(growable: true).obs;
+
+  var curConversationId = '';
+
+  Future<String?> loadMessagesFromService(
+    V2TimConversation conversation,
+    String? lastMsgId,
+    AutoScrollController _scrollController,
+  ) async {
+    if (lastMsgId == null && curConversationId != conversation.conversationID) {
+      messages.clear();
+      curConversationId = conversation.conversationID;
+    }
+
+    V2TimValueCallback<List<V2TimMessage>> result;
+    if (conversation.type == ConversationType.V2TIM_GROUP) {
+      result = await TimConversationService.to.messageManager
+          .getGroupHistoryMessageList(
+        groupID: conversation.groupID!,
+        count: 20,
+        lastMsgID: lastMsgId,
+      );
+    } else {
+      result = await TimConversationService.to.messageManager
+          .getC2CHistoryMessageList(
+        userID: conversation.userID!,
+        count: 20,
+        lastMsgID: lastMsgId,
+      );
+    }
+    var list = result.data ?? [];
+    if (lastMsgId == null) {
+      messages.value = list.reversed.toList();
+      _scrollController.scrollToIndex(
+        messages.length - 1,
+        preferPosition: AutoScrollPosition.begin,
+      );
+    } else {
+      //加载更多
+      if (list.isNotEmpty) {
+        messages.value = messages.reversed.toList(); //正常顺序
+        messages.addAll(list);
+        messages.value = messages.reversed.toList(); //反转一次
+      }
+    }
+    if (messages.isNotEmpty) {
+      return messages.first.msgID;
+    } else {
+      return '';
+    }
+  }
+
+  addMessage(V2TimMessage message) {
+    messages.add(message);
+  }
+}