Add explicit "use system language" TTS language.

Previously, if user set the TTS engine default language to the system
language, Settings app would save its value as empty string - which
is interpreted as "use system language", and makes it follow the change
of the device locale. This change introduces explicit "Use system language"
as an entry in the TTS default engine picker. This makes it consistent
with other pickers, like ones for keyboard and spellchecker.

Change-Id: Ibb4189be30bb9691ef2bd10e7fff883318eceae7

2 files changed, 23 insertions, 22 deletions

diff --git a/res/values/strings.xml b/res/values/strings.xml
index 4c605a4..bebc51b 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -3895,6 +3895,8 @@
 
     <!-- On main TTS Settings screen, in default settings section, setting default language for synthesized voice -->
     <string name="tts_default_lang_title">Language</string>
+    <!-- Entry in the TTS engine language/locale picker, when selected will try to default to the system language [CHAR LIMIT=50] -->
+    <string name="tts_lang_use_system">Use system language</string>
     <!-- On main TTS Settings screen, language summary if it can't default to system language [CHAR LIMIT=50] -->
     <string name="tts_lang_not_selected">Language not selected</string>
     <!-- On main TTS Settings screen, summary for default language for synthesized voice -->
diff --git a/src/com/android/settings/tts/TtsEngineSettingsFragment.java b/src/com/android/settings/tts/TtsEngineSettingsFragment.java
index 25ec1fd..ada6085 100644
--- a/src/com/android/settings/tts/TtsEngineSettingsFragment.java
+++ b/src/com/android/settings/tts/TtsEngineSettingsFragment.java
@@ -64,7 +64,6 @@ public class TtsEngineSettingsFragment extends SettingsPreferenceFragment implem
     private TextToSpeech mTts;
 
     private int mSelectedLocaleIndex = -1;
-    private int mSystemLocaleIndex = -1;
 
     private final TextToSpeech.OnInitListener mTtsInitListener = new TextToSpeech.OnInitListener() {
         @Override
@@ -201,8 +200,10 @@ public class TtsEngineSettingsFragment extends SettingsPreferenceFragment implem
             mLocalePreference.setEnabled(false);
             return;
         }
-        String currentLocale = mEnginesHelper.getLocalePrefForEngine(
-                getEngineName());
+        String currentLocale = "";
+        if (!mEnginesHelper.isLocaleSetToDefaultForEngine(getEngineName())) {
+            currentLocale = mEnginesHelper.getLocalePrefForEngine(getEngineName());
+        }
 
         ArrayList<Pair<String, String>> entryPairs =
                 new ArrayList<Pair<String, String>>(availableLangs.size());
@@ -231,21 +232,19 @@ public class TtsEngineSettingsFragment extends SettingsPreferenceFragment implem
             }
         });
 
-        String defaultLocaleStr = mEnginesHelper.getDefaultLocale();
-
         // Get two arrays out of one of pairs
-        mSelectedLocaleIndex = -1;
-        mSystemLocaleIndex = -1;
-        CharSequence[] entries = new CharSequence[availableLangs.size()];
-        CharSequence[] entryValues = new CharSequence[availableLangs.size()];
-        int i = 0;
+        mSelectedLocaleIndex = 0; // Will point to the R.string.tts_lang_use_system value
+        CharSequence[] entries = new CharSequence[availableLangs.size()+1];
+        CharSequence[] entryValues = new CharSequence[availableLangs.size()+1];
+
+        entries[0] = getActivity().getString(R.string.tts_lang_use_system);
+        entryValues[0] = "";
+
+        int i = 1;
         for (Pair<String, String> entry : entryPairs) {
             if (entry.second.equalsIgnoreCase(currentLocale)) {
                 mSelectedLocaleIndex = i;
             }
-            if (entry.second.equalsIgnoreCase(defaultLocaleStr)) {
-                mSystemLocaleIndex = i;
-            }
             entries[i] = entry.first;
             entryValues[i++] = entry.second;
         }
@@ -322,17 +321,17 @@ public class TtsEngineSettingsFragment extends SettingsPreferenceFragment implem
         mLocalePreference.setSummary(mLocalePreference.getEntries()[selectedLocaleIndex]);
         mSelectedLocaleIndex = selectedLocaleIndex;
 
-        if (mSelectedLocaleIndex == mSystemLocaleIndex) {
-            // Use empty locale, it will default to the system language
-            mEnginesHelper.updateLocalePrefForEngine(getEngineName(), "");
-        } else {
-            mEnginesHelper.updateLocalePrefForEngine(getEngineName(), locale);
-        }
+        mEnginesHelper.updateLocalePrefForEngine(getEngineName(), locale);
 
         if (getEngineName().equals(mTts.getCurrentEngine())) {
-            String[] localeArray = TtsEngines.parseLocalePref(locale);
-            if (localeArray != null) {
-                mTts.setLanguage(new Locale(localeArray[0], localeArray[1], localeArray[2]));
+            if (!locale.isEmpty()) {
+                String[] localeArray = TtsEngines.parseLocalePref(locale);
+                if (localeArray != null) {
+                    mTts.setLanguage(new Locale(localeArray[0], localeArray[1], localeArray[2]));
+                }
+            } else {
+                // Empty locale means "use system default"
+                mTts.setLanguage(Locale.getDefault());
             }
         }
     }