How do I serialize an object and save it to a file in Android?
I've tried this 2 options (read/write), with plain objects, array of objects (150 objects), Map:
Option1:
FileOutputStream fos = context.openFileOutput(fileName, Context.MODE_PRIVATE);
ObjectOutputStream os = new ObjectOutputStream(fos);
os.writeObject(this);
os.close();
Option2:
SharedPreferences mPrefs=app.getSharedPreferences(app.getApplicationInfo().name, Context.MODE_PRIVATE);
SharedPreferences.Editor ed=mPrefs.edit();
Gson gson = new Gson();
ed.putString("myObjectKey", gson.toJson(objectToSave));
ed.commit();
Option 2 is twice quicker than option 1
The option 2 inconvenience is that you have to make specific code for read:
Gson gson = new Gson();
JsonParser parser=new JsonParser();
//object arr example
JsonArray arr=parser.parse(mPrefs.getString("myArrKey", null)).getAsJsonArray();
events=new Event[arr.size()];
int i=0;
for (JsonElement jsonElement : arr)
events[i++]=gson.fromJson(jsonElement, Event.class);
//Object example
pagination=gson.fromJson(parser.parse(jsonPagination).getAsJsonObject(), Pagination.class);
Saving (w/o exception handling code):
FileOutputStream fos = context.openFileOutput(fileName, Context.MODE_PRIVATE);
ObjectOutputStream os = new ObjectOutputStream(fos);
os.writeObject(this);
os.close();
fos.close();
Loading (w/o exception handling code):
FileInputStream fis = context.openFileInput(fileName);
ObjectInputStream is = new ObjectInputStream(fis);
SimpleClass simpleClass = (SimpleClass) is.readObject();
is.close();
fis.close();