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@cmelchior
Created April 9, 2015 06:35
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What would you like to do?
Realm, GSON and primitive JSON arrays
// Make a custom Gson instance, with a custom TypeAdapter for each wrapper object.
// In this instance we only have RealmList<RealmInt> as a a wrapper for RealmList<Integer>
Type token = new TypeToken<RealmList<RealmInt>>(){}.getType();
Gson gson = new GsonBuilder()
.setExclusionStrategies(new ExclusionStrategy() {
@Override
public boolean shouldSkipField(FieldAttributes f) {
return f.getDeclaringClass().equals(RealmObject.class);
}
@Override
public boolean shouldSkipClass(Class<?> clazz) {
return false;
}
})
.registerTypeAdapter(token, new TypeAdapter<RealmList<RealmInt>>() {
@Override
public void write(JsonWriter out, RealmList<RealmInt> value) throws IOException {
// Ignore
}
@Override
public RealmList<RealmInt> read(JsonReader in) throws IOException {
RealmList<RealmInt> list = new RealmList<RealmInt>();
in.beginArray();
while (in.hasNext()) {
list.add(new RealmInt(in.nextInt()));
}
in.endArray();
return list;
}
})
.create();
// Convert JSON to objects as normal
List<MainObject> objects = gson.fromJson(json, new TypeToken<List<MainObject>>(){}.getType());
// Copy objects to Realm
realm.beginTransaction();
realm.copyToRealm(objects);
realm.commitTransaction();
[
{ "name" : "Foo",
"ints" : [1, 2, 3]
},
{ "name" : "Bar",
"ints" : []
}
]
public class MainObject extends RealmObject {
private String name;
private RealmList<RealmInt> ints;
// Getters and setters
}
public class RealmInt extends RealmObject {
private int val;
public RealmInt() {
}
public RealmInt(int val) {
this.val = val;
}
// Getters and setters
}
@trrkiran007
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trrkiran007 commented Sep 21, 2017

Nevermind, I figured it out myself..
instead of using default gson builder, I used like below:

 Gson gson = RealmParserUtil.getGson();
        retrofit = new Retrofit.Builder()
                .baseUrl(Res.string(R.string.appconfig_api_base_url))
                .addConverterFactory(GsonConverterFactory.create(gson))
                .client(builder.build())
                .build();

My Custom RealmParser:

public class RealmParserUtil {
    public static Gson getGson(){
        Gson gson = new GsonBuilder()
                .setLenient()
                .setExclusionStrategies(new ExclusionStrategy() {
                    @Override
                    public boolean shouldSkipField(FieldAttributes f) {
                        return f.getDeclaringClass().equals(RealmObject.class);
                    }


                    @Override
                    public boolean shouldSkipClass(Class<?> clazz) {
                        return false;
                    }
                })
                .create();
        return gson;
    }


    public static String serialize(Object object) {
        return getGson().toJson(object);
    }

    public static Object deserialize(String objectString, Type type) {
        Log.i("SuperCustomer", "Deserializing json response");
        return getGson().fromJson(objectString, type);
    }


    public static class ArrayToStringTypeAdapter extends TypeAdapter<RealmList<RealmString>> {

        @Override
        public void write(JsonWriter out, RealmList<RealmString> value) throws IOException {
            //out.value(String.valueOf(value));
        }

        @Override
        public RealmList<RealmString> read(JsonReader in) throws IOException {
            RealmList<RealmString> list = new RealmList<RealmString>();

            boolean isArray = (in.peek() == JsonToken.BEGIN_ARRAY);

            if(isArray) {
                in.beginArray();
                while (in.hasNext()) {
                    list.add(new RealmString(in.nextString()));
                }
                in.endArray();
            }
            return list;
        }
    };
}

In my model class I used this:

    @JsonAdapter(RealmParserUtil.ArrayToStringTypeAdapter.class)
    private RealmList<RealmString> strInterests;

Thank you @Joisar for your gist, it helped me a lot.

@egpayawal
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egpayawal commented Jul 9, 2018

@cmelchior
I implemented your solution but its not working for me. Do you have an update code for parsing primitive array string or int?
thanks!

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