Convert ForeignCollection to ArrayList - ORMLite, Gson and Android
Solution 1
Is this a good plan or should I write two completely separate ways of extracting the Image URL from the data, NOT converting the object from ForeignCollection to ArrayList?
It should work. I don't see an easy way to do it otherwise.
Some points:
- Is there some way to mark the
ForeignCollection
as transient so it is ignored when transferring over JSON? Then you can use the sameUser
object for both JSON and ORMLite. - Some sort of
hydrate()
method would be good so it would convert frommedia
->mediaCollection
and vice versa. - If you need to load JSON transferred images into the foreign collection then you should use the
Dao.getEmptyForeignCollect(...)
method. Once you have the collection, you can add images into it and they will be added to the tables.
If it is a good plan, how do I convert a ForeignCollection to an ArrayList?
This is easier. A ForeignCollection
is a Collection
. You can just do a:
media = new ArrayList<Image>(mediaCollection);
So your User.getMedia()
method should check for null
and if so, convert from the mediaCollection
field.
Solution 2
Just to Convert from @ForeignCollectionField
to ArrayList<Object>
you can do that:
ArrayList<Object> taskFieldsList = new ArrayList<Object>(your collection);
hope it's help you.
wuliwong
You can find out about me at http://patrickjustinbradley.com. I currently work on various tech products an Atlanta-based real estate company. I've worked at a couple other startups in the past as well as Oracle. On my own, I created a music collecting/sharing website http://www.muusical.com and a place to find Swift language tutorials http://www.sososwift.com. In May 2010, I received a PhD in physics from Georgia Tech. My research was nonlinear, computational physics applied to problems in neuroscience. My specialties are Rails/React with some experience in Go and Python.
Updated on June 10, 2022Comments
-
wuliwong about 2 years
I apologize if I'm not super clear with my explanation but I'll add to and edit this question for clarity if requested.
I am developing an Android app which receives data through an external API and stores data locally using ORMLite. Prior to storing data locally and using ORMLite I had models which retrieved JSON from the server and parsed it via:
Gson gson = new Gson(); String result = ApiClient.httpPost("/user_route"); User user = gson.fromJson(result, User.class);
The User class was defined
public class User { int id; String name; ArrayList<Image> media; }
And the Image class:
public class Image { int id; int creator_id; String url; }
This is a simplified representation of the models and methods but I believe I've kept all the relevant information. BTW,
media
is a JSON object which contains theImages
.Now I'm trying to also store the data locally. In order to have the relationship between Users and Images using ORMLite it seems you have to employ ForeignCollection class and @ForeignCollectionField annotation. I don't believe Gson can directly parse the Json for the
media
field in the User class as a ForeignCollection object, so I thought I needed to create two fieldsmediaCollection
andmedia
.Using ORMLite the User class now looks like this:
@DatabaseTable(tableName = "Users") public class User { @DatabaseField(generatedId = true) int id; @DatabaseField String name; @ForeignCollectionField ForeignCollection<Image> mediaCollection; ArrayList<Image> media; }
The Image class with ORMLite looks like this:
@DatabaseTable(tableName = "Images") public class Image { @DatabaseField(generatedId = true) int id; @DatabaseField(foreign=true, foreignAutoCreate=true, foreignAutoRefresh=true) private User user; @DatabaseField int creator_id; @DatabaseField String url; }
How the flow of the app works is first I hit the local database for a User. I perform some logic which then determines if I need to actually hit the server to 'update' or 'refresh' the User data.
Whether the data comes locally or from the remote server, I need to display the
Image
in the same view. As it stands now, the URL for theImage
is stored in different types of objects depending on whether the data is local or remote. What I would like to do is if theImage
is stored in aForeginCollection
object, convert that object into anArrayList
and then proceed with the rest of my code which extracts theImage
URL and displays it.I guess there are two questions.
Is this a good plan or should I write two completely separate ways of extracting the
Image
URL from the data, NOT converting the object fromForeignCollection
toArrayList
?If it is a good plan, how do I convert a
ForeginCollection
to anArrayList
?