Is it possible to save an entire array (or even ArrayList) to the android app data?
As far as I know you can only do stuff like putInt, putBoolean or putString.... But what about more complex data-types? Is there a way to do that?
Or do I have to convert the whole array to a String first, and then parse it to an array again on load?
for complex data-types use
Bundle bundle = new Bundle();
bundle.putSerializable("key", object);
intent.putExtra("bundle", bundle);
EDit: or for Arrays use
putStringArray(key,value);
I think yuou dont know there is also functions like putFloatArray(key,Value),putStringArray(key,value).You can use those.
If by "app data" you mean SharedPreferences, then no, you can only save simple types.
However you can save application state via Activities' onSaveInstanceState / onRestoreInstanceState as described here: Saving Android Activity state using Save Instance State
Note that this saves state per Activity, so it's best to have a main activity where you save app state.
You can serialize almost any form of data and save it as a byte stream byte[]
After serialization, store with:
putByteArray("key", serializedData);
You need to implement Parcelable. You should have a look at this tutorial Passing ArrayList across activities
