用来在应用中存储键值对配置

context.getSharedPreferences(“prefName”, Context.MODE_PRIVATE) get SharedPreferecnes instance
sharedPref.getXXX(“keyName”, defaultValue) get value from SharedPreferences
sharedPref.edit() get editor(SharedPreference.Editor)
editor.putXXX(“key-name”, value) put value
editor.commit() commit the changes