feat(message): 添加语音消息展示功能

- 引入 VoiceItem 组件用于展示语音消息
- 在 MessageItem 中增加对 VOICE 类型消息的处理逻辑
- 根据消息类型动态渲染语音消息组件
- 优化时间标签构建逻辑，提升代码可读性- 移除冗余的空行和不必要的间距设置- 保持非文本消息的占位符显示方式不变

lib/widget/message/message_item.dart

@@ -4,6 +4,7 @@ import 'package:im_flutter_sdk/im_flutter_sdk.dart';
 
 import 'text_item.dart';
 import 'image_item.dart';
+import 'voice_item.dart';
 
 class MessageItem extends StatelessWidget {
   final EMMessage message;
@@ -39,16 +40,23 @@ class MessageItem extends StatelessWidget {
         formattedTime: formatMessageTime(message.serverTime),
       );
     }
-    
+    // 处理语音消息
+    else if (message.body.type == MessageType.VOICE) {
+      final voiceBody = message.body as EMVoiceMessageBody;
+      return VoiceItem(
+        voiceBody: voiceBody,
+        isSentByMe: isSentByMe,
+        showTime: shouldShowTime(),
+        formattedTime: formatMessageTime(message.serverTime),
+      );
+    }
+
     // 非文本消息显示占位符
     return Column(
       children: [
         if (shouldShowTime()) _buildTimeLabel(),
         Container(
-          padding: EdgeInsets.symmetric(
-            horizontal: 16.w,
-            vertical: 8.h,
-          ),
+          padding: EdgeInsets.symmetric(horizontal: 16.w, vertical: 8.h),
           child: Text('不支持的消息类型'),
         ),
       ],
@@ -60,7 +68,7 @@ class MessageItem extends StatelessWidget {
     if (previousMessage == null) {
       return true; // 第一条消息显示时间
     }
-    
+
     // 判断距离上一条消息是否超过20分钟（1200000毫秒）
     return (message.serverTime - previousMessage!.serverTime) > 1200000;
   }
@@ -68,22 +76,15 @@ class MessageItem extends StatelessWidget {
   // 构建时间标签
   Widget _buildTimeLabel() {
     final formattedTime = formatMessageTime(message.serverTime);
-    
+
     return Container(
       alignment: Alignment.center,
-      padding: EdgeInsets.symmetric(
-        horizontal: 16.w,
-      ),
+      padding: EdgeInsets.symmetric(horizontal: 16.w),
       child: Container(
-        padding: EdgeInsets.symmetric(
-          horizontal: 12.w,
-        ),
+        padding: EdgeInsets.symmetric(horizontal: 12.w),
         child: Text(
           formattedTime,
-          style: TextStyle(
-            fontSize: 12.sp,
-            color: Colors.grey,
-          ),
+          style: TextStyle(fontSize: 12.sp, color: Colors.grey),
         ),
       ),
     );
@@ -96,7 +97,7 @@ class MessageItem extends StatelessWidget {
     final today = DateTime(now.year, now.month, now.day);
     final yesterday = DateTime(now.year, now.month, now.day - 1);
     final messageDate = DateTime(date.year, date.month, date.day);
-    
+
     if (messageDate.isAtSameMomentAs(today)) {
       // 今天的消息显示时间
       return '今天 ${date.hour.toString().padLeft(2, '0')}:${date.minute.toString().padLeft(2, '0')}';
@@ -108,6 +109,4 @@ class MessageItem extends StatelessWidget {
       return '${date.month}月${date.day}日 ${date.hour.toString().padLeft(2, '0')}:${date.minute.toString().padLeft(2, '0')}';
     }
   }
-
-
-}
+}