Json 在 Android 中向 RecyclerView 发送文本

Question

我的 RecyclerView 需要帮助。我的 SQL 数据库中有一个 atring 数组，如下所示：

{"success":true,"0":{"order_number":"078","typ_first":"E3rft","typ_last":"Split","order_date_time":"2016-10-11 19:20:03"},"1":{"order_number":"166","typ_first":"E483f","typ_last":"Split_test","order_date_time":"2016-10-12 18:39:30"}}

在我的 RecyclerView 中，我有以下字段：

order_number
typ_all（输入第一个和最后一个）
date(只有日期没有时间)

这就是我获取字符串数组的方式：

String plansData = plansPreferenceData.getString("plansPreferenceData", "");

这是我将数据设置到 RecyclerView 的方式：

// Set plan data
Plans plan = new Plans("123", "E3rft Split", "11.10.2016");
// Add Object to list
planList.add(plan);

// Notify data changes
pAdapter.notifyDataSetChanged();

我的Plansclass:

public class Plans {
    private String planTitle, planType, planDate;

    public Plans(String planTitle, String planType, String planDate) {
        this.planTitle = planTitle;
        this.planType = planType;
        this.planDate = planDate;
    }

    public void setPlanTitle(String planTitle) {
        this.planTitle = planTitle;
    }

    public String getPlanTitle() {
        return planTitle;
    }

    public void setPlanType(String planType) {
        this.planType = planType;
    }

    public String getPlanType() {
        return planType;
    }

    public void setPlanDate(String planDate) {
        this.planDate = planDate;
    }

    public String getPlanDate() {
        return planDate;
    }
}

我的onCreateView:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view = inflater.inflate(R.layout.fragment_training, container, false);

    preparePlansData();

    return view;
}

我的preparePlansData():

private void preparePlansData() {

    // Set plan data
    Plans plan = new Plans("123", "fkfjfjeje", "21.04.1977");
    // Add Object to list
    planList.add(plan);

    plan = new Plans("test", "tttt", "22.01.2017");
    planList.add(plan);

    // Notify data changes
    pAdapter.notifyDataSetChanged();

}

我的问题是如何将信息从字符串数组中提取到我的适配器中？我还需要在添加之前格式化日期。感谢您的帮助！

Answer 1

在此处阅读有关 Gson 的信息：

http://guides.codepath.com/android/leveraging-the-gson-library

之后你将能够像这样编写代码：

 Type type = new TypeToken<Map<Integer, Plans>>(){}.getType();
 Map<Integer, Plans> myMap = gson.fromJson("your json from db", type);

并在你的适配器中使用这个 map.values()

你的 Plans class 应该是这样的：

class Plans {
    String order_number;
    String typ_first;
    String typ_last;
    String order_date_time;
}

如果您想要其他字段名称，则必须使用 @SerializedName 注释

最后，你应该写这样的东西，（我不知道语法是不是100%没有IDE现在打开）：

private void preparePlansData() {
    String plansData = plansPreferenceData.getString("plansPreferenceData", "");
    Type type = new TypeToken<Map<Integer, Plans>>(){}.getType();
    Map<Integer, Plans> myMap = gson.fromJson(plansData, type); 
    planList.addAll(myMap.values());

    // Notify data changes
    pAdapter.notifyDataSetChanged();
}

并修改您的模型 class:

public class Plans {
    @SerializedName("order_number")
    String planTitle;
    @SerializedName("typ_last") 
    String planType; 
    @SerializedName("order_date_time")  
    String planDate;
    ....

希望对你有所帮助

Answer 2

检查此代码（您可以删除@Test 注释）：

class Plans {
    String typ_firstString;
    String typ_last;
    String order_date_time;

    public Plans(String typ_firstString, String typ_last, String order_date_time) {
        this.typ_firstString = typ_firstString;
        this.typ_last = typ_last;
        this.order_date_time = order_date_time;
    }
}

class PlansResponse {
    boolean status;
    List<Plans> plans;
}

@Test
public void testPlacesResponseDeserializer() { 
    Gson gson = new GsonBuilder()
            .registerTypeAdapter(PlansResponse.class, new PlansResponseDeserializer())
            .create();
    String jsonString = "{\"success\":true,\"0\":{\"order_number\":\"078\",\"typ_first\":\"E3rft\",\"typ_last\":\"Split\",\"order_date_time\":\"2016-10-11 19:20:03\"},\"1\":{\"order_number\":\"166\",\"typ_first\":\"E483f\",\"typ_last\":\"Split_test\",\"order_date_time\":\"2016-10-12 18:39:30\"}}";
    PlansResponse plansResponse = gson.fromJson(jsonString, PlansResponse.class);

    assert plansResponse.status == true;
    assert plansResponse.plans.size() == 2;
}

class PlansResponseDeserializer implements JsonDeserializer<PlansResponse> {

    private String getElementAsString(JsonObject jsonObject, String key) {
        JsonElement element = jsonObject.get(key);
        return element.getAsString();
    }

    @Override
    public PlansResponse deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
        PlansResponse plansResponse = new PlansResponse();

        List<Plans> plansList = new ArrayList<>();
        Gson gson = new Gson();
        Type type = new TypeToken<Map<String, JsonObject>>(){}.getType();
        Map<String, JsonElement> map = gson.fromJson(json, type);

        for(Map.Entry<String, JsonElement> entry : map.entrySet()) {
            String key = entry.getKey();

            if("success".equals(key)) {
                JsonPrimitive jsonPrimitive = (JsonPrimitive) entry.getValue();
                plansResponse.status = jsonPrimitive.getAsBoolean();
                continue;
            }

            JsonObject jsonObject = (JsonObject)entry.getValue();
            String typ_firstString = getElementAsString(jsonObject, "typ_first");
            String typ_last = getElementAsString(jsonObject, "typ_last");
            String order_date_time = getElementAsString(jsonObject, "order_date_time");
            plansList.add(new Plans(typ_firstString, typ_last, order_date_time));
        }
        plansResponse.plans = plansList;
        return plansResponse;
    }
}

Json 在 Android 中向 RecyclerView 发送文本

Json text to RecyclerView in Android

java

android

json

gson

json-deserialization