[update] use aliyun andriod sdk

lib/utils/tts_util.dart

@@ -0,0 +1,23 @@
+import 'package:flutter/services.dart';
+
+class TtsUtil {
+  static const MethodChannel _channel =
+      MethodChannel('com.example.ai_chat_assistant/tts');
+
+  static Future<T?> execute<T>(String method,
+      [Map<Object, Object>? arguments]) {
+    return _channel.invokeMethod(method, arguments);
+  }
+
+  static Future<bool> start(bool isChinese) async {
+    return await execute('start', {'isChinese': isChinese});
+  }
+
+  static Future<void> send(String text) async {
+    await execute('send', {'text': text});
+  }
+
+  static Future<void> stopTts() async {
+    await execute('stop');
+  }
+}