SharedPreferences保存数组

//用SharedPreferences保存/取出arrayList数组

/**
* desc:保存对象

 * @param context * @param key * @param obj 要保存的对象，只能保存实现了serializable的对象 * modified: */public static void saveObject(Context context,String key ,Object obj){    try {        // 保存对象        SharedPreferences.Editor sharedata = context.getSharedPreferences("FILE_NAME", 0).edit();        //先将序列化结果写到byte缓存中，其实就分配一个内存空间        ByteArrayOutputStream bos=new ByteArrayOutputStream();        ObjectOutputStream os=new ObjectOutputStream(bos);        //将对象序列化写入byte缓存        os.writeObject(obj);        //将序列化的数据转为16进制保存        String bytesToHexString = bytesToHexString(bos.toByteArray());        //保存该16进制数组        sharedata.putString(key, bytesToHexString);        sharedata.commit();    } catch (IOException e) {        e.printStackTrace();        Log.e("", "保存obj失败");    }}/** * desc:将数组转为16进制 * @param bArray * @return * modified: */public static String bytesToHexString(byte[] bArray) {    if(bArray == null){        return null;    }    if(bArray.length == 0){        return "";    }    StringBuffer sb = new StringBuffer(bArray.length);    String sTemp;    for (int i = 0; i < bArray.length; i++) {        sTemp = Integer.toHexString(0xFF & bArray[i]);        if (sTemp.length() < 2)            sb.append(0);        sb.append(sTemp.toUpperCase());    }    return sb.toString();}/** * desc:获取保存的Object对象 * @param context * @param key * @return * modified: */public static Object readObject(Context context,String key ){    try {        SharedPreferences sharedata = context.getSharedPreferences("FILE_NAME", 0);        if (sharedata.contains(key)) {            String string = sharedata.getString(key, "");            if(TextUtils.isEmpty(string)){                return null;            }else{                //将16进制的数据转为数组，准备反序列化                byte[] stringToBytes = StringToBytes(string);                ByteArrayInputStream bis=new ByteArrayInputStream(stringToBytes);                ObjectInputStream is=new ObjectInputStream(bis);                //返回反序列化得到的对象                Object readObject = is.readObject();                return readObject;            }        }    } catch (StreamCorruptedException e) {        // TODO Auto-generated catch block        e.printStackTrace();    } catch (IOException e) {        // TODO Auto-generated catch block        e.printStackTrace();    } catch (ClassNotFoundException e) {        // TODO Auto-generated catch block        e.printStackTrace();    }    //所有异常返回null    return null;}/** * desc:将16进制的数据转为数组 * @param data * @return * modified: */public static byte[] StringToBytes(String data){    String hexString=data.toUpperCase().trim();    if (hexString.length()%2!=0) {        return null;    }    byte[] retData=new byte[hexString.length()/2];    for(int i=0;i<hexString.length();i++)    {        int int_ch;  // 两位16进制数转化后的10进制数        char hex_char1 = hexString.charAt(i); ////两位16进制数中的第一位(高位*16)        int int_ch1;        if(hex_char1 >= '0' && hex_char1 <='9')            int_ch1 = (hex_char1-48)*16;   //// 0 的Ascll - 48        else if(hex_char1 >= 'A' && hex_char1 <='F')            int_ch1 = (hex_char1-55)*16; //// A 的Ascll - 65        else            return null;        i++;        char hex_char2 = hexString.charAt(i); ///两位16进制数中的第二位(低位)        int int_ch2;        if(hex_char2 >= '0' && hex_char2 <='9')            int_ch2 = (hex_char2-48); //// 0 的Ascll - 48        else if(hex_char2 >= 'A' && hex_char2 <='F')            int_ch2 = hex_char2-55; //// A 的Ascll - 65        else            return null;        int_ch = int_ch1+int_ch2;        retData[i/2]=(byte) int_ch;//将转化后的数放入Byte里    }    return retData;}