优化了老师端的等待状态判断逻辑

lib/pages/student/room/video/teacher_video.dart

@@ -1,4 +1,8 @@
+import 'package:agora_rtc_engine/agora_rtc_engine.dart';
 import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+
+import '../viewmodel/stu_room_vm.dart';
 
 class TeacherVideo extends StatefulWidget {
   const TeacherVideo({super.key});
@@ -10,10 +14,44 @@ class TeacherVideo extends StatefulWidget {
 class _TeacherVideoState extends State<TeacherVideo> {
   @override
   Widget build(BuildContext context) {
+    final vm = context.read<StuRoomVM>();
+    final teacherInfo = vm.teacherInfo;
+
+    ///没开始
+    if (vm.roomStatus == 0) {
+      return _empty("自习室还没开始");
+    }
+
+    ///开始
+    if (vm.roomStatus == 1 && vm.engine != null) {
+      if (teacherInfo == null) {
+        return _empty("老师不在自习室内");
+      }
+      if (teacherInfo.online == 0) {
+        return _empty("老师掉线了，请耐心等待");
+      }
+      return AgoraVideoView(
+        controller: VideoViewController(
+          rtcEngine: vm.engine!,
+          canvas: VideoCanvas(
+            uid: vm.teacherInfo!.userId,
+          ),
+        ),
+      );
+    }
+
+    ///结束
+    if (vm.roomStatus == 2) {
+      return _empty("自习室已结束");
+    }
+    return _empty("加载中");
+  }
+
+  Widget _empty(String title) {
     return SafeArea(
       child: Align(
         child: Text(
-          "画面准备中",
+          title,
           style: TextStyle(color: Colors.white),
         ),
       ),