feat: add AI voice transcription fallback for domestic Android ROMs

kouyu_english/lib/features/dialogue/dialogue_flow.dart

@@ -113,6 +113,8 @@ class _DialoguePageState extends State<DialoguePage> {
   String? hint;
   bool listening = false;
   bool recording = false;
+  bool transcribing = false;
+  bool aiVoiceRecording = false;
   bool playingRecording = false;
   bool usedVoice = false;
   bool transcriptEdited = false;
@@ -368,27 +370,94 @@ class _DialoguePageState extends State<DialoguePage> {
   }
 
   Future<void> _toggleListening() async {
+    if (aiVoiceRecording) {
+      final path = await VoiceService.instance.stopRecording();
+      if (!mounted) return;
+      setState(() {
+        aiVoiceRecording = false;
+        listening = false;
+        transcribing = true;
+      });
+      if (path != null) {
+        final config = widget.state.aiConfig;
+        final transcribed = await AiService.instance.transcribeAudio(
+          filePath: path,
+          provider: config.provider,
+          endpoint: config.endpoint,
+          model: config.model,
+        );
+        if (mounted) {
+          setState(() {
+            transcribing = false;
+            if (transcribed != null && transcribed.trim().isNotEmpty) {
+              controller.text = transcribed.trim();
+              usedVoice = true;
+              lastTranscript = transcribed.trim();
+              transcriptEdited = false;
+            }
+          });
+          if (transcribed == null || transcribed.trim().isEmpty) {
+            ScaffoldMessenger.of(context).showSnackBar(
+              const SnackBar(content: Text('未识别到清晰语音，请再试一次或使用键盘输入。')),
+            );
+          }
+        }
+      } else {
+        if (mounted) setState(() => transcribing = false);
+      }
+      return;
+    }
+
     if (listening) {
       await VoiceService.instance.stopListening();
       if (mounted) setState(() => listening = false);
       return;
     }
-    final available = await VoiceService.instance.startListening((text, _) {
-      if (!mounted) return;
-      setState(() {
-        controller.text = text;
-        usedVoice = true;
-        lastTranscript = text;
-        transcriptEdited = false;
-      });
-    });
+
+    final available = await VoiceService.instance.startListening(
+      (text, _) {
+        if (!mounted) return;
+        setState(() {
+          controller.text = text;
+          usedVoice = true;
+          lastTranscript = text;
+          transcriptEdited = false;
+        });
+      },
+      onStatus: (status) {
+        if (mounted && (status == 'notListening' || status == 'done')) {
+          setState(() => listening = false);
+        }
+      },
+      onError: (err) {
+        if (mounted) {
+          setState(() => listening = false);
+        }
+      },
+    );
+
+    if (!available) {
+      final recordStarted = await VoiceService.instance.startRecording();
+      if (mounted) {
+        setState(() {
+          aiVoiceRecording = recordStarted;
+          listening = recordStarted;
+        });
+        if (recordStarted) {
+          ScaffoldMessenger.of(context).showSnackBar(
+            const SnackBar(content: Text('已启动麦克风录音，说完后再次点击麦克风，AI 将自动转写英文。')),
+          );
+        } else {
+          ScaffoldMessenger.of(context).showSnackBar(
+            const SnackBar(content: Text('无法访问麦克风，请检查手机录音权限。')),
+          );
+        }
+      }
+      return;
+    }
+
     if (!mounted) return;
     setState(() => listening = available);
-    if (!available) {
-      ScaffoldMessenger.of(
-        context,
-      ).showSnackBar(const SnackBar(content: Text('语音识别不可用；你仍可使用文字输入。')));
-    }
   }
 
   Future<void> _toggleRecording() async {
@@ -572,11 +641,22 @@ class _DialoguePageState extends State<DialoguePage> {
                 filled: true,
                 fillColor: AppColors.surface,
                 prefixIcon: IconButton(
-                  tooltip: listening ? '停止录音' : '语音输入',
-                  icon: Icon(
-                    listening ? Icons.stop_circle_outlined : Icons.mic_none,
-                  ),
-                  onPressed: _toggleListening,
+                  tooltip: transcribing
+                      ? '正在 AI 识别…'
+                      : (listening ? '停止录音并识别' : '语音输入'),
+                  icon: transcribing
+                      ? const SizedBox(
+                          width: 18,
+                          height: 18,
+                          child: CircularProgressIndicator(strokeWidth: 2),
+                        )
+                      : Icon(
+                          listening
+                              ? Icons.stop_circle
+                              : Icons.mic_none,
+                          color: listening ? Colors.redAccent : null,
+                        ),
+                  onPressed: transcribing ? null : _toggleListening,
                 ),
                 suffixIcon: IconButton(
                   icon: const Icon(Icons.send),