java - Change context language according to the current device language -

alright know it's okay have many languages in single app . couldnt find proper way . here want start , want activity detect android device language , change simple text

 "@string/hello" 

according . know method locale.getdefault().getlanguage() dont know how apply . secondly want give user option change language if wants .

public class mainactivity extends activity {  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);       locale.getdefault().getlanguage(); } 

here simple layout

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools"  android:layout_width="match_parent" android:layout_height="match_parent"     android:paddingleft="@dimen/activity_horizontal_margin" android:paddingright="@dimen/activity_horizontal_margin" android:paddingtop="@dimen/activity_vertical_margin" android:paddingbottom="@dimen/activity_vertical_margin" tools:context="com.vermelha.tourword.mainactivity">  <textview android:text="@string/hello"     android:layout_height="wrap_content"     android:layout_width="wrap_content"/>  </relativelayout> 

values

<?xml version="1.0" encoding="utf-8"?> <resources>  <string name="app_name">tour word</string> <string name="title_activity_main">mainactivity</string> <string name="hello">hello</string> <string name="action_settings">settings</string>  </resources> 

values-tr

<?xml version="1.0" encoding="utf-8"?> <resources> <string name="app_name">tour word</string> <string name="title_activity_main">mainactivity</string> <string name="hello">merhaba!</string> <string name="action_settings">ayralar</string>  </resources> 

you have create new folder in res: values-es example spanish, values-pt example portuguese

create new strings.xml file

put same string there

values/strings.xml

<string name="app_about_title">about</string> 

values-es/strings.xml

<string name="app_about_title">acerca</string> 

values-pt/strings.xml

<string name="app_about_title">sobre</string> 

automatically when use @string/app_about_title or via code r.string.app_about_title translated if use language doesn't has translation, use standard (values fodler)