当前的activity切换到后台，切换语言，回到原来的activity，原来的activity不见，出现又一新activity。
原因：没有在AndroidManifest.xml 中申明android:configChanges
android:configChanges
Lists configuration changes that the activity will handle itself. When a configuration change occurs at runtime, the activity is shut down and restarted by default, but declaring a configuration with this attribute will prevent the activity from being restarted. Instead, the activity remains running and its onConfigurationChanged()
解决在AndroidManifest.xml中申明 android:configChanges="locale"