Moved access of Language classes for OneSignalPrefs

* Made OneSignal.preferences public for accessibility in Language classes
* Moved callbacks for OneSignalPrefs from LanguageContext and LanguageProviderAppDefined classes to OneSignal.preferences

Author: tanaynigam

OneSignalSDK/onesignal/src/main/java/com/onesignal/OneSignal.java

@@ -419,7 +419,7 @@ static Activity getCurrentActivity() {
    private static String userId = null, emailId = null;
    private static int subscribableStatus;
 
-   private static LanguageContext languageContext = null;
+   public static LanguageContext languageContext = null;
 
    // Is the init() of OneSignal SDK finished yet
    private static boolean initDone;

OneSignalSDK/onesignal/src/main/java/com/onesignal/language/LanguageContext.java

@@ -1,6 +1,5 @@
 package com.onesignal.language;
-import com.onesignal.OSUtils;
-import com.onesignal.OneSignalPrefs;
+import com.onesignal.OneSignal;
 import static com.onesignal.language.LanguageProviderAppDefined.PREFS_OS_LANGUAGE;
 
 /*
@@ -11,8 +10,8 @@ public class LanguageContext {
     private LanguageProvider strategy;
 
     public LanguageContext() {
-        if ( OneSignalPrefs.getString(
-                OneSignalPrefs.PREFS_ONESIGNAL, PREFS_OS_LANGUAGE, null) != null) {
+        if ( OneSignal.preferences.getString(
+                OneSignal.preferences.getPreferencesName(), PREFS_OS_LANGUAGE, null) != null) {
             this.strategy = new LanguageProviderAppDefined();
         }
         else {

OneSignalSDK/onesignal/src/main/java/com/onesignal/language/LanguageProviderAppDefined.java

@@ -1,21 +1,18 @@
 package com.onesignal.language;
-
-import com.onesignal.OSUtils;
 import com.onesignal.OneSignal;
-import com.onesignal.OneSignalPrefs;
 
 public class LanguageProviderAppDefined implements LanguageProvider{
     public static final String PREFS_OS_LANGUAGE = "PREFS_OS_LANGUAGE";
 
     public void setLanguage(String language) {
-        OneSignalPrefs.saveString(
-                OneSignalPrefs.PREFS_ONESIGNAL,
+        OneSignal.preferences.saveString(
+                OneSignal.preferences.getPreferencesName(),
                 PREFS_OS_LANGUAGE,
                 language);
     }
 
     public String getLanguage() {
-        return OneSignalPrefs.getString(
-                OneSignalPrefs.PREFS_ONESIGNAL, PREFS_OS_LANGUAGE,"en");
+        return OneSignal.preferences.getString(
+                OneSignal.preferences.getPreferencesName(), PREFS_OS_LANGUAGE, "en");
     }
 }