2026.6.5 二维码扫码提示问题

lib/pages/home/scan_page.dart

@@ -30,14 +30,20 @@ class ScanPage extends StatefulWidget {
 class _ScanPageState extends State<ScanPage> {
   final MobileScannerController _controller = MobileScannerController();
   bool _torchOn = false;
+  bool _hasPermission = true; // 默认有权限
 
   @override
   void initState() {
     super.initState();
+
+    // 监听 controller 的状态变化
+    _controller.addListener(_onControllerStateChange);
+
   }
 
   @override
   void dispose() {
+    _controller.removeListener(_onControllerStateChange); // 移除监听
     _controller.dispose();
     super.dispose();
   }
@@ -72,6 +78,27 @@ class _ScanPageState extends State<ScanPage> {
 
   }
 
+
+  // 监听权限状态变化
+  void _onControllerStateChange() {
+    final error = _controller.value.error;
+
+    if (error != null && mounted) {
+      // 检查是否是权限被拒绝的错误
+      if (error.errorCode == MobileScannerErrorCode.permissionDenied) {
+        setState(() {
+          _hasPermission = false;
+        });
+        print('相机权限被拒绝');
+      }
+    } else if (_controller.value.isRunning && mounted) {
+      // 如果相机正在运行，说明有权限
+      setState(() {
+        _hasPermission = true;
+      });
+    }
+  }
+
   // 人脸识别跳转
   void goToFace(Map<String, dynamic> stuInfo) async {
     print('navigate to face with $stuInfo');
@@ -234,6 +261,33 @@ class _ScanPageState extends State<ScanPage> {
               },
             ),
           ),
+
+
+          // 权限遮罩 - 放在最上层覆盖所有内容
+          if (!_hasPermission)
+            Container(
+              color: Colors.black,
+              child: const Center(
+                child: Column(
+                  mainAxisAlignment: MainAxisAlignment.center,
+                  children: [
+                    Icon(Icons.camera_alt, color: Colors.white, size: 64),
+                    SizedBox(height: 20),
+                    Text(
+                      '需要相机权限才能使用扫码功能',
+                      style: TextStyle(color: Colors.white, fontSize: 16),
+                    ),
+                    SizedBox(height: 10),
+                    Text(
+                      '请在设置中允许相机权限',
+                      style: TextStyle(color: Colors.white70, fontSize: 14),
+                    ),
+                  ],
+                ),
+              ),
+            ),
+
+
         ],
       ),
     );