Android uses sharedpreferences to save objects

Core principle:

Serialization of objects

Steps

1. To save the object to implement serialization serializable

2. Save the serialized object as a string (the practice in this article is to save as a byte array in a string that is converted to 16 binary)

3. Deserializing a saved string into an object

Here is the complete code

Step 1. To save the object to implement serialization serializable

public class Sertest implements serializable{    private String name;    private int age;}

Step 2. Saves the serialized object as a string (the practice of this article is to save as a byte array in a string that is converted to 16 binary)

Step 3: Deserialize the saved string into an object

    /** * Desc: Save Object * @param context * @param key * @param obj object to save, save only objects that implement serializable * MoD            Ified: */public static void Saveobject (Context context,string key, Object obj) {try {//Save Object            Sharedpreferences.editor sharedata = context.getsharedpreferences (FILENAME, 0). Edit ();            First writes the serialized result to the byte cache, actually allocates one memory space Bytearrayoutputstream bos=new Bytearrayoutputstream ();            ObjectOutputStream os=new ObjectOutputStream (BOS);            Serializes an object to the byte cache Os.writeobject (obj);            Convert serialized data to 16 binary save String bytestohexstring = bytestohexstring (Bos.tobytearray ());            Save the 16 binary array sharedata.putstring (key, bytestohexstring);        Sharedata.commit ();            } catch (IOException e) {e.printstacktrace ();        LOG.E ("", "Save obj Failed"); }}/** * desc: Convert Array to 16 * @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: Gets the Saved Object objects * @param context * @param key * @return * Modified: */Public OBJ ECT ReadObject (Context context,string key) {try {sharedpreferences sharedata = Context.getsharedprefer            Ences (FILENAME, 0);                 if (Sharedata.contains (key)) {string string = sharedata.getstring (Key, "");                 if (Textutils.isempty (string)) {return null; }else{//16 inData into an array, ready to deserialize byte[] Stringtobytes = Stringtobytes (string);                       Bytearrayinputstream bis=new Bytearrayinputstream (stringtobytes);                       ObjectInputStream is=new ObjectInputStream (bis);                       Returns the deserialized object readobject = Is.readobject ();                 return readobject; }}} catch (Streamcorruptedexception e) {//TODO auto-generated catch block e.pr        Intstacktrace ();        } catch (IOException e) {//TODO auto-generated catch block E.printstacktrace ();        } catch (ClassNotFoundException e) {//TODO auto-generated catch block E.printstacktrace ();            }//All exceptions return null return null;     }/** * desc: Converting 16 data into an array * <p> Creator: Nie Xuyang, 2014-5-25 a.m. 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