flexible message

lib/widgets/chat_box.dart

@@ -13,23 +13,36 @@ class ChatBox extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return ListView.builder(
-      controller: scrollController,
-      itemCount: messages.length,
-      reverse: true,
-      padding: const EdgeInsets.symmetric(horizontal: 12),
-      itemBuilder: (context, index) {
-        final message = messages[messages.length - 1 - index];
-        final isTop = index == messages.length - 1;
-        final isBottom = index == 0;
-        return Padding(
-          padding: EdgeInsets.only(
-            top: isTop ? 0 : 6,
-            bottom: isBottom ? 0 : 6,
-          ),
-          child: ChatBubble(message: message),
-        );
-      },
+    return Container(
+      constraints: const BoxConstraints(
+        minHeight: 60,
+      ),
+      decoration: BoxDecoration(
+        border: Border.all(
+          color: Colors.grey, // 边框颜色
+          width: 1.0,         // 边框宽度
+        ),
+        borderRadius: BorderRadius.circular(8.0), // 边框圆角
+      ),
+      child: ListView.builder(
+        controller: scrollController,
+        itemCount: messages.length,
+        reverse: true,
+        padding: const EdgeInsets.symmetric(horizontal: 12),
+        shrinkWrap: true,
+        itemBuilder: (context, index) {
+          final message = messages[messages.length - 1 - index];
+          final isTop = index == messages.length - 1;
+          final isBottom = index == 0;
+          return Padding(
+            padding: EdgeInsets.only(
+              top: isTop ? 0 : 6,
+              bottom: isBottom ? 0 : 6,
+            ),
+            child: ChatBubble(message: message),
+          );
+        },
+      ),
     );
   }
 }