Android Save object as blob in sqlite

android, gridview, sqlite

Solution

The way I store data as BLOB in my DB, is by converting them to JSON and then storing the bytes. e.g.

ArrayList<Person> persons  = new ArrayList<>();
Gson gson = new Gson();
ContentValues values = new ContentValues();
values.put(MyProvider.KEY_DATA, gson.toJson(persons).getBytes());
// insert or update the DB

And to get the list back

byte[] blob = cursor.getBlob(cursor.getColumnIndex(MyProvider.KEY_DATA));
String json = new String(blob);
Gson gson = new Gson();
ArrayList<Person> persons = gson.fromJson(json, new TypeToken<ArrayList<Person>>()
                                 {}.getType());

Edit: to answer your last question, you should store your data (list of items).

Problem

is this right. I have this `gridview`. I want to save its item as blob in sqlite. so when i open the list of save data in sqlite ill just load the save `items` and call `adapter.notifyDataSetChanged` to my `gridview` I tried this one but I get `NotSerializableException` error List items = new ArrayList(); ``` public static byte[] serializeObject(Object o) { ByteArrayOutputStream bos = new ByteArrayOutputStream(); try { ObjectOutput out = new ObjectOutputStream(bos); out.writeObject(o); out.close(); // Get the bytes of the serialized object byte[] buf = bos.toByteArray(); return buf; } catch (IOException ioe) { Log.e("serializeObject", "error", ioe); return null; } } ``` my insert row ``` public long insertRow(byte[] data) { /* * CHANGE 3: */ // TODO: Update data in the row with new fields. // TODO: Also change the function's arguments to be what you need! // Create row's data: ContentValues initialValues = new ContentValues(); initialValues.put(KEY_DATA, data); // Insert it into the database. return db.insert(DATABASE_TABLE, null, initialValues); } ``` then I insert the serialize object ``` myDB.insertRow(MyDBAdapter.serializeObject(items)); ``` also i'm confuse. should i save the adapter or the list of items'?

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