1.广角/主摄切换按钮已上移：

2.新增 isSwitchingLens 状态、避免切换镜头    stop 按钮禁用，不会触发 stopRecording
倍距按钮禁用，避免连续切换
ViewModel 层也兜底：isSwitchingLens=true 时直接拒绝 stop
3.合并失败兜底提示

test/features/recording/view_model_recording_test.dart

@@ -1,9 +1,12 @@
+import 'dart:async';
+
 import 'package:flutter/services.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:permission_handler/permission_handler.dart';
 import 'package:recording_tool/features/recording/model/model_recording_session.dart';
 import 'package:recording_tool/features/recording/platform/recording_channel_names.dart';
+import 'package:recording_tool/features/recording/platform/recording_platform.dart';
 import 'package:recording_tool/features/recording/view-model/view_model_recording.dart';
 
 void main() {
@@ -255,6 +258,125 @@ void main() {
         expect(session.errorMessage, '切换镜头失败，请重试');
       },
     );
+
+    test('sets switching lens while native zoom request is pending', () async {
+      final completer = Completer<Map<String, dynamic>>();
+      TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+          .setMockMethodCallHandler(
+            const MethodChannel(RecordingChannelNames.method),
+            (call) => completer.future,
+          );
+      final container = ProviderContainer();
+      addTearDown(container.dispose);
+      final notifier = container.read(recordingViewModelProvider.notifier);
+
+      final future = notifier.setZoomRatio(2);
+      await Future<void>.delayed(Duration.zero);
+
+      expect(
+        container.read(recordingViewModelProvider).session.isSwitchingLens,
+        isTrue,
+      );
+
+      completer.complete(<String, dynamic>{
+        'zoomRatio': 2.0,
+        'minZoomRatio': 1.0,
+        'maxZoomRatio': 3.0,
+      });
+      await future;
+
+      expect(
+        container.read(recordingViewModelProvider).session.isSwitchingLens,
+        isFalse,
+      );
+    });
+  });
+
+  group('RecordingViewModel.stopRecording', () {
+    test('does not call native stop while switching lens', () async {
+      final calls = <MethodCall>[];
+      TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+          .setMockMethodCallHandler(
+            const MethodChannel(RecordingChannelNames.method),
+            (call) async {
+              calls.add(call);
+              return <String, dynamic>{};
+            },
+          );
+      final container = ProviderContainer();
+      addTearDown(container.dispose);
+      final notifier = container.read(recordingViewModelProvider.notifier);
+      // ignore: invalid_use_of_protected_member
+      notifier.state = container
+          .read(recordingViewModelProvider)
+          .copyWith(
+            session: const RecordingSessionState(
+              status: RecordingStatus(state: RecordingState.recording),
+              isSwitchingLens: true,
+            ),
+          );
+
+      await notifier.stopRecording();
+
+      expect(calls, isEmpty);
+    });
+
+    test(
+      'stores segment output paths when native save falls back to parts',
+      () async {
+        TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+            .setMockMethodCallHandler(
+              const MethodChannel(RecordingChannelNames.method),
+              (call) async {
+                switch (call.method) {
+                  case 'stopRecording':
+                    return <String, dynamic>{
+                      'outputPath': 'content://recordings/part1',
+                      'status': <String, dynamic>{
+                        'state': 'error',
+                        'message': 'Merge failed',
+                      },
+                      'fileSaved': false,
+                      'fileErrorMessage': 'Merge failed',
+                      'segmentOutputPaths': <String>[
+                        'content://recordings/part1',
+                        'content://recordings/part2',
+                      ],
+                    };
+                  case 'initializePreview':
+                    return <String, dynamic>{'state': 'previewing'};
+                  case 'getZoomCapabilities':
+                    return <String, dynamic>{
+                      'zoomRatio': 1.0,
+                      'minZoomRatio': 1.0,
+                      'maxZoomRatio': 3.0,
+                    };
+                }
+                return <String, dynamic>{};
+              },
+            );
+        final container = ProviderContainer();
+        addTearDown(container.dispose);
+        final notifier = container.read(recordingViewModelProvider.notifier);
+        // ignore: invalid_use_of_protected_member
+        notifier.state = container
+            .read(recordingViewModelProvider)
+            .copyWith(
+              session: const RecordingSessionState(
+                status: RecordingStatus(state: RecordingState.recording),
+              ),
+            );
+
+        await notifier.stopRecording();
+
+        final session = container.read(recordingViewModelProvider).session;
+        expect(session.fileSaveFailed, isTrue);
+        expect(session.segmentOutputPaths, <String>[
+          'content://recordings/part1',
+          'content://recordings/part2',
+        ]);
+      },
+    );
   });
 
   group('recordingFileSavePermissionsForHost', () {

test/features/recording/widget_recording_hud_test.dart

@@ -10,6 +10,8 @@ void main() {
     double minZoomRatio = 1.0,
     double maxZoomRatio = 3.0,
     bool isRecording = false,
+    bool isSwitchingLens = false,
+    Future<void> Function()? onStop,
     ValueChanged<double>? onZoomSelected,
   }) async {
     await tester.pumpWidget(
@@ -25,12 +27,13 @@ void main() {
                 notificationsGranted: true,
                 isRecording: isRecording,
                 isStartingRecording: false,
+                isSwitchingLens: isSwitchingLens,
                 isTouchLocked: false,
                 zoomRatio: zoomRatio,
                 minZoomRatio: minZoomRatio,
                 maxZoomRatio: maxZoomRatio,
                 onStart: () async {},
-                onStop: () async {},
+                onStop: onStop ?? () async {},
                 onOpenDnd: () {},
                 onOpenBattery: () {},
                 onToggleTouchLock: () {},
@@ -112,7 +115,7 @@ void main() {
     );
 
     await tester.tap(find.text('0.5x'));
-    await tester.pump();
+    await tester.pump(const Duration(milliseconds: 350));
 
     expect(selected, 0.5);
   });
@@ -128,7 +131,7 @@ void main() {
     );
 
     await tester.tap(find.text('0.6x'));
-    await tester.pump();
+    await tester.pump(const Duration(milliseconds: 350));
 
     expect(selected, 0.6);
   });
@@ -155,7 +158,7 @@ void main() {
     expect(mainButton.enabled, isFalse);
 
     await tester.tap(find.text('0.6x'));
-    await tester.pump();
+    await tester.pump(const Duration(milliseconds: 350));
 
     expect(selected, 0.6);
   });
@@ -183,8 +186,45 @@ void main() {
     expect(mainButton.enabled, isTrue);
 
     await tester.tap(find.text('1x'));
-    await tester.pump();
+    await tester.pump(const Duration(milliseconds: 350));
 
     expect(selected, 1.0);
   });
+
+  testWidgets('disables stop button while switching lens', (tester) async {
+    var stopped = false;
+    await pumpHud(
+      tester,
+      minZoomRatio: 0.6,
+      isRecording: true,
+      isSwitchingLens: true,
+      onStop: () async => stopped = true,
+    );
+
+    await tester.tap(find.byType(GestureDetector).last);
+    await tester.pump();
+
+    expect(stopped, isFalse);
+  });
+
+  testWidgets('disables zoom buttons while switching lens', (tester) async {
+    double? selected;
+    await pumpHud(
+      tester,
+      minZoomRatio: 0.6,
+      isRecording: true,
+      isSwitchingLens: true,
+      onZoomSelected: (ratio) => selected = ratio,
+    );
+
+    final ultraWideButton = tester.widget<TextButton>(
+      find.ancestor(of: find.text('0.6x'), matching: find.byType(TextButton)),
+    );
+
+    expect(ultraWideButton.enabled, isFalse);
+    await tester.tap(find.text('0.6x'));
+    await tester.pump(const Duration(milliseconds: 350));
+
+    expect(selected, isNull);
+  });
 }