Android SharedPreferences保存和讀取對象
阿新 • • 發佈:2017-08-10
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挺好用的,歡迎大家復制使用
SharedPreferences保存和讀取對象
1.首先要序列化對象(以下是序列化實體類的樣例,不方便貼出實體類全部的代碼)
public class LoginResult extends BaseResult implements Serializable{ private static final long serialVersionUID = 1L; private String mobiletoken;
2.保存和讀取對象的封裝
public class ObjectSaveUtil { private final static String FILENAME = "login_data_save"; private final static String KEY = "loginResult"; /** * desc:保存對象 * @param context * @param key * @param obj 要保存的對象,僅僅能保存實現了serializable的對象 * modified: */ public static void saveObject(Context context,Object obj){ try { // 保存對象 SharedPreferences.Editor sharedata = context.getSharedPreferences(FILENAME, 0).edit(); //先將序列化結果寫到byte緩存中,事實上就分配一個內存空間 ByteArrayOutputStream bos=new ByteArrayOutputStream(); ObjectOutputStream os=new ObjectOutputStream(bos); //將對象序列化寫入byte緩存 os.writeObject(obj); //將序列化的數據轉為16進制保存 String bytesToHexString = bytesToHexString(bos.toByteArray()); //保存該16進制數組 sharedata.putString(KEY, bytesToHexString); sharedata.commit(); } catch (IOException e) { e.printStackTrace(); Log.e("", "保存obj失敗"); } } /** * desc:將數組轉為16進制 * @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:獲取保存的Object對象 * @param context * @param key * @return * modified: */ public static Object readObject(Context context){ try { SharedPreferences sharedata = context.getSharedPreferences(FILENAME, 0); if (sharedata.contains(KEY)) { String string = sharedata.getString(KEY, ""); if(TextUtils.isEmpty(string)){ return null; }else{ //將16進制的數據轉為數組。準備反序列化 byte[] stringToBytes = StringToBytes(string); ByteArrayInputStream bis=new ByteArrayInputStream(stringToBytes); ObjectInputStream is=new ObjectInputStream(bis); //返回反序列化得到的對象 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(); } //全部異常返回null return null; } /** * desc:將16進制的數據轉為數組 * <p>創建人:聶旭陽 , 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; // 兩位16進制數轉化後的10進制數 char hex_char1 = hexString.charAt(i); ////兩位16進制數中的第一位(高位*16) int int_ch3; if(hex_char1 >= '0' && hex_char1 <='9') int_ch3 = (hex_char1-48)*16; //// 0 的Ascll - 48 else if(hex_char1 >= 'A' && hex_char1 <='F') int_ch3 = (hex_char1-55)*16; //// A 的Ascll - 65 else return null; i++; char hex_char2 = hexString.charAt(i); ///兩位16進制數中的第二位(低位) int int_ch4; if(hex_char2 >= '0' && hex_char2 <='9') int_ch4 = (hex_char2-48); //// 0 的Ascll - 48 else if(hex_char2 >= 'A' && hex_char2 <='F') int_ch4 = hex_char2-55; //// A 的Ascll - 65 else return null; int_ch = int_ch3+int_ch4; retData[i/2]=(byte) int_ch;//將轉化後的數放入Byte裏 } return retData; } }
挺好用的,歡迎大家復制使用
Android SharedPreferences保存和讀取對象