The use of SharedPreferences for Android data storage

Introduction to SharedPreferences

SharedPreferences is a data storage method in android. It is stored in the memory in the form of xml in the form of key-value key-value pairs. The files are stored in the /data/data//shared_prefs directory. SharedPreferences
initialization

getSharedPreferences(name,mode) The
name and mode parameters represent memory space naming and access permission mode
name respectively. Memory space naming is to open up a storage space belonging to your app in memory.
Mode access permission
MODE_APPEND : additional storage
MODE_PRIVATE : private Storage
MODE_WORLD_READABLE open storage mode other apps can read
MODE_WORLD_WRITEABLE open storage mode other apps can write and get editing objects

Common methods
SharedPreferences.Editor edit = sp.edit();
edit.clear();//Clear data
edit.putString();//Save string
edit.putInt(); //Save int
edit.putLong() ; //Store in long
edit.putBoolean(); //Store in boolean
edit.putFloat(); //Store in float
edit.putStringSet();//Store in set
sp.getString(); //Get string
sp .getInt(); // take int
sp.getBoolean();// take boolean
sp.getLong(); // take long
sp.getAll(); // take map

本人封装的sp 管理工具

    public class SPUtils {
    /**
     * sq 构造 持有context 对象
     * @param context
     */
    public static SharedPreferences sp;
    public static Context context;


    public  SPUtils(Context context) {
        this.context = context;
        if (sp==null){
            sp = context.getSharedPreferences(Constant.SPKEY, Context.MODE_PRIVATE);
        }
    }


    /**
     * getString/char
      * @param key 字段名
     * @return value 返回值
     */
    public static String getString(String key){
        String value = sp.getString(key, "");
        if (!TextUtils.isEmpty(value)){
            return value;
        }else {
            return Constant.BACKERROR+"";
        }
    }

    /**
     * getInt方法
     * @param key 字段名
     *
     * @return value int返回值
     */
    public static int getInt(String key){
        int value = sp.getInt(key, 0);
        if (value!=0){
            return value;
        }else {
            return Constant.BACKERROR;
        }
    }

    /**
     * getLong 方法
     *
     * @param key 字段名
     * @return Long返回值
     */
    public static Long getLong(String key){
        Long value = sp.getLong(key, 0);
        if (value!=0){
            return value;
        }else {
            return Long.valueOf(Constant.BACKERROR);
        }
    }
    /**
     *  putString 方法
     *
     * @param key 字段名
     * @param value 字段值
     */
    public static void putString(String key,String value){
        sp.edit().putString(key,value).commit();

    }
    /**
     *  putInt 方法
     *
     * @param key 字段名
     * @param value 字段值
     */
    public static void putInt(String key,int value){
        sp.edit().putInt(key,value).commit();

    }
    /**
     *  putLong 方法
     *
     * @param key 字段名
     * @param value 字段值
     */
    public static void putLong(String key,Long value){
        sp.edit().putLong(key,value).commit();

    }
        // 清除数据
    public static void clearSpSpace(){
        sp.edit().clear().commit();
    }

}