Add friendly log messages for Android and HarmonyOs TTS users. (#2427)

@@ -5,6 +5,7 @@
 #include "sherpa-onnx/csrc/jieba.h"
 
 #include "sherpa-onnx/csrc/file-utils.h"
+#include "sherpa-onnx/csrc/macros.h"
 
 namespace sherpa_onnx {
 
@@ -19,6 +20,21 @@ std::unique_ptr<cppjieba::Jieba> InitJieba(const std::string &dict_dir) {
   std::string idf = dict_dir + "/idf.utf8";
   std::string stop_word = dict_dir + "/stop_words.utf8";
 
+#if __ANDROID_API__ >= 9 || defined(__OHOS__)
+  if (dict[0] != '/') {
+    SHERPA_ONNX_LOGE(
+        "You need to follow our examples to copy the jieba dict directory from "
+        "the assets folder to an external storage directory");
+
+    SHERPA_ONNX_LOGE(
+        "Hint: Please see\n"
+        "https://github.com/k2-fsa/sherpa-onnx/blob/master/android/"
+        "SherpaOnnxTtsEngine/app/src/main/java/com/k2fsa/sherpa/onnx/tts/"
+        "engine/TtsEngine.kt#L193\n"
+        "The function copyDataDir()\n");
+  }
+#endif
+
   AssertFileExists(dict);
   AssertFileExists(hmm);
   AssertFileExists(user_dict);

@@ -247,6 +247,22 @@ static std::vector<int64_t> CoquiPhonemesToIds(
 void InitEspeak(const std::string &data_dir) {
   static std::once_flag init_flag;
   std::call_once(init_flag, [data_dir]() {
+
+#if __ANDROID_API__ >= 9 || defined(__OHOS__)
+    if (data_dir[0] != '/') {
+      SHERPA_ONNX_LOGE(
+          "You need to follow our examples to copy the espeak-ng-data "
+          "directory from the assets folder to an external storage directory.");
+
+      SHERPA_ONNX_LOGE(
+          "Hint: Please see\n"
+          "https://github.com/k2-fsa/sherpa-onnx/blob/master/android/"
+          "SherpaOnnxTtsEngine/app/src/main/java/com/k2fsa/sherpa/onnx/tts/"
+          "engine/TtsEngine.kt#L188\n"
+          "The function copyDataDir()\n");
+    }
+#endif
+
     int32_t result =
         espeak_Initialize(AUDIO_OUTPUT_SYNCHRONOUS, 0, data_dir.c_str(), 0);
     if (result != 22050) {