将对象存储到SharedPreferences里

来源：互联网发布：ubuntu防火墙编辑：程序博客网时间：2024/05/21 21:42
原理：
需要将对象序列化，然后将序列化后的对象以字符串的方式保存在手机中
具体代码如下
package com.bestours.youlun.utils;import android.app.Activity;import android.content.Context;import android.content.SharedPreferences;import android.text.TextUtils;import android.util.Log;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;/** * Created by sunny on 16/4/7. */public class SPUtil {    /**     * 从起启动应用，保存的搜索条件清空     *     * @param mContext     */    public static void initOption(Activity mContext) {        SPUtil.saveObject(mContext, "destinationShow", null);        SPUtil.saveObject(mContext, "companyShow", null);        SPUtil.saveObject(mContext, "nightShow", null);        SPUtil.saveObject(mContext, "dayShow", null);    }    /**     * desc:获取保存的Object对象     *     * @param context     * @param key     * @return modified:     */    public static Object readObject(Context context, String key) {        Object readObject = null;        try {            SharedPreferences sharedata = context.getSharedPreferences("config", 0);            if (sharedata.contains(key)) {                String string = sharedata.getString(key, "");                if (TextUtils.isEmpty(string)) {                    readObject = 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                    readObject = is.readObject();                }            }        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();            readObject = null;        }        //所有异常返回null        return readObject;    }    /**     * desc:将16进制的数据转为数组     * <p>创建人：聂旭阳 , 2014-5-25 上午11:08:33</p>     *     * @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;    }    /**     * 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("config", 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();    }}
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