反序列化RealList< RealmString>时出错.进入列表< String> [英] Error deserializing a RealList<RealmString> Into List<String>

问题描述

由于Realm无法使用促销类型(包括String)，因此我试图实现JsonDeserializer，就像

Due to Realm inability to work with promotive types, which include Strings, I'm trying to implement a JsonDeserializer just like in this question.

问题在于，我对为什么出现以下错误感到困惑:

The issue is that I'm baffled on to why I'm getting the following error:

W/System.err:com.google.gson.JsonSyntaxException:java.lang.IllegalStateException:预期为BEGIN_OBJECT，但为STRING

W/System.err: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING

这是Json的一部分:"tags": ["GLUTEN FREE", "NUT FREE"],

This is part of the Json: "tags": ["GLUTEN FREE", "NUT FREE"],

我的RealmString:

My RealmString:

public class RealmString extends RealmObject {
    private String value;

    public RealmString() {
    }

    public RealmString(String value) {
        this.value = value;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }
}

改装的Pojo的一部分:

Part of the retrofited Pojo:

public class Entity extends RealmObject {

    @SerializedName("tags")
    private RealmList<RealmString> tags = null;
}

..和反序列化器:

public class StringRealmListConverter implements JsonDeserializer<RealmList<RealmString>> {

    @Override
    public RealmList<RealmString> deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
            throws JsonParseException {

        RealmList<RealmString> realmStrings = new RealmList<>();
        JsonArray ja = json.getAsJsonArray();
        for (JsonElement je : ja) {
            realmStrings.add((RealmString) context.deserialize(je, RealmString.class));
        }

        return realmStrings;
    }
}

我正在这里注册:

public Gson provideGson() {
    return new GsonBuilder()
            .registerTypeAdapter(Food.class, new FoodDeserializer())
            .registerTypeAdapter(new TypeToken<RealmList<RealmString>>() {}.getType(),
                    new StringRealmListConverter())
            .create();
}

edit 这是FoodDeserializer.之所以陷入混乱，是因为我们不得不使用继承而不是继承"来取悦领域之神:

edit Here's the FoodDeserializer. It's in this mess because we had to use Composition over Inheritance in order to please the Realm gods:

public class FoodDeserializer implements JsonDeserializer<Food> {
    public static final String TAG = FoodDeserializer.class.getSimpleName();

    Gson mHelperGson;

    public FoodDeserializer() {
        mHelperGson = new GsonBuilder().create();
    }

    @Override
    public Food deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
        String type = json.getAsJsonObject().get("responseType").getAsString();
        switch (type) {
            case "Platter":
                return parsePlatter(json);
            case "FoodItem":
                return parseFoodItem(json);
            default:
                return null;
        }
    }

    private PlatterEntity parsePlatter(JsonElement json) {

        FoodEntity food = mHelperGson.fromJson(json, new TypeToken<FoodEntity>() {
        }.getType());

        ArrayList<FoodItemEntity> items = new ArrayList<>();
        JsonElement je1 = json.getAsJsonObject().get("items");
        if (je1 != null) {
            JsonArray list = je1.getAsJsonArray();
            if (list != null) {
                items = mHelperGson.fromJson(list.toString(), new TypeToken<List<FoodItemEntity>>() {
                }.getType());
            }
        }

        return new PlatterEntity(food, items);
    }

    private FoodItemEntity parseFoodItem(JsonElement json) {

        FoodEntity food = mHelperGson.fromJson(json, new TypeToken<FoodEntity>() {
        }.getType());

        Boolean readyToEat = null;
        JsonElement je1 = json.getAsJsonObject().get("readyToEat");
        if (je1 != null) {
            readyToEat = je1.getAsBoolean();
        }

        String heatingInstructions = null;
        JsonElement je2 = json.getAsJsonObject().get("heatingInstructions");
        if (je2 != null) {
            heatingInstructions = je2.getAsString();
        }

        ArrayList<IngredientEntity> ingredients = new ArrayList<>();
        JsonElement je3 = json.getAsJsonObject().get("ingredients");
        if (je3 != null) {
            JsonArray list = je3.getAsJsonArray();
            if (list != null) {
                ingredients = mHelperGson.fromJson(list.toString(), new TypeToken<List<IngredientEntity>>() {
                }.getType());
            }
        }

        NutritionEntity foodNutritions = mHelperGson.fromJson(json, new TypeToken<NutritionEntity>() {
        }.getType());

        return new FoodItemEntity(food, readyToEat, heatingInstructions, ingredients, foodNutritions);
    }
}

我想在TypeAdapter上使用JsonDeserializer，但是任何帮助将不胜感激，谢谢！

I would like to use a JsonDeserializer over TypeAdapter, but any help will be appreciated, thanks!

推荐答案

原来我的感觉是对的.我必须将StringRealmListConverter添加到FoodDeserializable构造函数中，如下所示:

Turns out my feelings were right. I had to add the StringRealmListConverter to the FoodDeserializable constructor, like this:

    public FoodDeserializer() {
        mHelperGson = new GsonBuilder()
            .registerTypeAdapter(new TypeToken<RealmList<RealmString>>() {
                    }.getType(),
                    new StringRealmListConverter())
            .create();
    }

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