Force Localisation Android

 Step 1:Create One java class which extends from 'Application'  
 public class LocaleApplication extends Application{  
   private Locale mLocale = null;  
   @Override  
   public void onConfigurationChanged(Configuration newConfig) {  
     super.onConfigurationChanged(newConfig);  
     if (mLocale != null) {  
       newConfig.locale = mLocale;  
       Locale.setDefault(mLocale);  
       getBaseContext().getResources().updateConfiguration(newConfig, getBaseContext().getResources().getDisplayMetrics());  
     }  
   }  
   @Override  
   public void onCreate() {  
     super.onCreate();  
    updateLocale(BuildConfig.LOCALE);  
   }  
   public void updateLocale(Locale locale) {  
     Configuration config = getBaseContext().getResources().getConfiguration();  
     if (!config.locale.equals(locale)) {  
       mLocale = new Locale(locale.getLanguage(),locale.getCountry());  
       Locale.setDefault(mLocale);  
       config.locale = mLocale;  
       getBaseContext().getResources().updateConfiguration(config, getBaseContext().getResources().getDisplayMetrics());  
       // reload challenge and achievement strings - these were created with the previous locale  
     }  
   }  
 }  
 Step 2: Mention this class name in Android manifest file under <application> tag  
 <application  
   android:name="LocaleApplication"  
   android:allowBackup="true"  
   android:icon="@mipmap/ic_launcher"  
   android:label="@string/app_name"  
   android:supportsRtl="true"  
   android:theme="@style/AppTheme">  
 Step 3: Take appropriate resource folders like values-es-rCO,values-el etc.   
 Step 4: Add below steps in build.gradle for resource configurations.  
 defaultConfig {  
   applicationId "com.example.ankitpr1.forcelocalisation_android"  
   minSdkVersion 15  
   targetSdkVersion 23  
   versionCode 1  
   versionName "1.0"  
   buildConfigField 'java.util.Locale', 'LOCALE_SPANISH_LATAM', 'new java.util.Locale(\"es\",\"US\")'  
   buildConfigField 'java.util.Locale', 'LOCALE_Greek', 'new java.util.Locale(\"el\")'  
 }  
 productFlavors {  
   esus{  
     applicationId 'com.colombia.us'  
     resConfigs 'es-rCO'  
     buildConfigField 'java.util.Locale', 'LOCALE', 'new java.util.Locale(\"es\",\"CO\")'  
     versionCode 3  
     versionName "3.0"  
     // ! any change in Locale, should be applied in defaultConfig as well  
   }  
   Greek {  
     applicationId 'com.test.greek'  
     resConfigs 'el'  
     buildConfigField 'java.util.Locale', 'LOCALE', 'new java.util.Locale(\"el\")'  
     versionCode 2  
     versionName "2.1"  
     l  
   }  
 }  
 //List all flavours in project to be used for check current flavour against others  
 productFlavours.all {  
   flavour ->  
     def flavourName = String.valueOf(flavour.name)  
     defaultConfig.buildConfigField 'String', 'Flavour_' + flavourName , '\"' + flavourName + '\"'  
 }  

Build variant type according to Locale

 Add below code under android--defaultConfig in build.gradle file  
 buildConfigField 'java.util.Locale', 'LOCALE_SPANISH_LATAM', 'new java.util.Locale(\"es\",\"US\")'  
 productFlavors {  
   esus{  
     applicationId 'com.praveena.test.us'  
     resConfigs 'es-rUS'  
     buildConfigField 'java.util.Locale', 'LOCALE', 'new java.util.Locale(\"es\",\"US\")'  
   }  
 }  
 By using this we can select the build variant type while running.