SharedPreferences 외부 파일로 저장 / 불러오기

저장

        val preferences = getDefaultSharedPreferences(BaseApp.appContext)
        val keys = preferences.all
        val properties = Properties()
        for ((key, value1) in keys) {
            val value = value1.toString()
            properties.setProperty(key, value)
        }
        try {
            val root = Environment.getExternalStorageDirectory()
            val dir = root.absolutePath.toString() + "/appname"
            val fileDir = File(dir)
            if (!fileDir.exists()){
                fileDir.mkdir()
            }
            val path = root.absolutePath.toString() + "/appname/data.txt"
            val file = File(path)
            val fileOut = FileOutputStream(file)
            properties.storeToXML(fileOut, "External Preferences")
            fileOut.close()
        } catch (e: Exception) {
            e.printStackTrace()
        } catch (e: IOException) {
            e.printStackTrace()
        }

불러오기

try {
            val preferences = PreferenceManager.getDefaultSharedPreferences(BaseApp.appContext)

            val root = Environment.getExternalStorageDirectory()
            val dir = root.absolutePath.toString() + "/appname"
            val fileDir = File(dir)
            if (!fileDir.exists()){
                return
            }
            val path = root.absolutePath.toString() + "/appname/data.txt"
            val file = File(path)
            val fileInput = FileInputStream(file)
            val properties = Properties()
            properties.loadFromXML(fileInput)
            fileInput.close()
            val enuKeys = properties.keys()
            val editor = preferences.edit()
            while (enuKeys.hasMoreElements()) {
                val key = enuKeys.nextElement() as String
                val value = properties.getProperty(key)
                editor.putString(key, value)
                editor.commit()
            }
        } catch (e: FileNotFoundException) {
            e.printStackTrace()
        } catch (e: IOException) {
            e.printStackTrace()
        }