Android Java 检索 JSON 值并作为对象存储在列表中

Question

我想连接到可以有多个页面的 Api 链接，并将所有 JSON 值作为一个对象存储在一个列表中。

Here is a Api link example with multiple pages, note the number as last being the page you're on.

到目前为止我遇到但无法解决的问题。 doInBackground 作为构造函数类 apiRootObject 的返回类型以及如何反序列化 Json 结果，这是合乎逻辑的为什么它不起作用，因为我从 AsyncTask 扩展但我不知道如何解决这个问题或其他途径拿走。

这是我目前的代码。

在我的 Activity.java 中调用初始函数

String userSearchRequest = search_activity_data.getString("userSearchRequest");
String URL = "http://www.gw2spidy.com/api/v0.9/json/item-search/" + userSearchRequest + "/";
//Api link example with multiple pages = "http://www.gw2spidy.com/api/v0.9/json/item-search/Iron"
AsyncFetch parkingInfoFetch = new AsyncFetch(this);
parkingInfoFetch.setOnResponse(this);
parkingInfoFetch.execute(URL);

从上述代码调用的我的 AsyncFetch.java 类 公共类 AsyncFetch 扩展 AsyncTask {

    public AsyncFetch(Context context) {
        this.context = context;
    }

    private Context context;
    private JSONObject jsonObject;
    private onResponse onResponse;

    public void setOnResponse(onResponse onResponse) {
        this.onResponse = onResponse;
    }

    @Override
    protected apiRootObject doInBackground(String... params) { //Incompatible return type
        // TODO Auto-generated method stub

        apiRootObject apiRootObject = null;
        apiRootObject tempApiRootObject = null;
        int page = 0;

        try {
            do {
                HttpGet get = new HttpGet(params[0] + page);
                HttpClient client = new DefaultHttpClient();
                HttpResponse response = client.execute(get);
                HttpEntity entity = response.getEntity();
                String result = EntityUtils.toString(entity);

                //jsonObject = new JSONObject(result);
                tempApiRootObject = /*Deserialize into <RootObject>(result)*/

                if (apiRootObject == null){
                    apiRootObject = tempApiRootObject;
                }
                else{
                    apiRootObject.results.addAll(tempApiRootObject.results);
                    apiRootObject.count += tempApiRootObject.count;
                }
                page++;
            }

            while(tempApiRootObject.last_page != tempApiRootObject.page);

        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
        e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return apiRootObject;
    }

    @Override
    protected void onPostExecute(JSONObject result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
        this.onResponse.onResponse(result);
    }

    public interface onResponse {
        public void onResponse(JSONObject object);
    }
}

然后返回到 activity.java，所有内容都被添加到 onResponse 函数的列表中。

public void onResponse(JSONObject object) {//Still expecting a JSONObject while I am changing this return type
        Log.i("gw2Log", object.toString());

        apiRootObject resultClass = new apiRootObject();

        try {
            resultClass.setCount(object.getInt("count"));
            resultClass.setPage(object.getInt("page"));
            resultClass.setLast_page(object.getInt("last_page"));
            resultClass.setTotal(object.getInt("total"));
            JSONArray list = new JSONArray(object.getString("results"));

            for (int i = 0; i < resultClass.getCount(); i++) {
                JSONObject resultsObject = list.getJSONObject(i);
                apiResults temp = new apiResults();
                temp.setData_id(resultsObject
                        .getInt("data_id"));
                temp.setName(resultsObject
                        .getString("name"));
                temp.setRarity(resultsObject
                        .getInt("rarity"));
                temp.setRestriction_level(resultsObject
                        .getInt("restriction_level"));
                temp.setImg(resultsObject
                        .getString("img"));
                temp.setType_id(resultsObject
                        .getInt("type_id"));
                temp.setSub_type_id(resultsObject
                        .getInt("sub_type_id"));
                temp.setPrice_last_changed(resultsObject
                        .getString("price_last_changed"));
                temp.setMax_offer_unit_price(resultsObject
                        .getInt("max_offer_unit_price"));
                temp.setMin_sale_unit_price(resultsObject
                        .getInt("min_sale_unit_price"));
                temp.setOffer_availability(resultsObject
                        .getInt("offer_availability"));
                temp.setSale_availability(resultsObject
                        .getInt("sale_availability"));
                temp.setSale_price_change_last_hour(resultsObject
                        .getInt("sale_price_change_last_hour"));
                temp.setOffer_price_change_last_hour(resultsObject
                        .getInt("offer_price_change_last_hour"));
                resultClass.addObject(temp);
            }

        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        for(int i = 0; i < resultClass.count; i++) {
            Log.i("gw2Log", resultClass.getObject(i).name);

        }

    }

当然还有apiResults和apiRootObject两个构造函数类。

编辑： 如果您点击问题顶部的链接，您会返回大量 JSON 值，如果创建了更多新页面，则每个页面可以有 50 个这样的结果。

我想连接到这个 Api 链接，并检索所有返回的值。如果有多个页面，它需要遍历所有现有页面并将这些 JSON 值添加到完全相同的列表中。

我之前在 c# 中问过一个类似的问题，现在我已经让它工作了，但我现在需要在 Android Java 中完全相同。对于 android java，我被告知我需要使用 AsyncTask 来建立连接并在应用程序的后台执行所有这些操作。如果有更好或更简单的方法，请赐教。

Answer 1

使用Retrofit 可能还为时不晚。

Answer 2

gson 是将 json 转换为类的最简单方法。

//your class
public class Foo {
  public final int bar;
  public final String bazz;
  public foo(int bar, String bazz) {
    this.bar = bar;
    this.bazz = bazz;
  }
}

//your json
{  "bar" : 4, "bazz" : "interesting content" }

//your gson call
Gson gson = new Gson();
Foo foo = gson.fromJson(json, Foo.class);

---

你甚至可以做嵌套对象，它会反序列化它们。

public class FooHaver {
    public final String prop1;
    public final Foo foo;
}

//your json
{ "prop1" : "more content", "foo" : { "bar" : 4, "bazz" : "even more content" } }

您还可以将 json 数组作为数组或任何您想要的类型的 java 列表进行

Answer 3

试试这个

    @Override
    protected apiRootObject doInBackground(String... params) { //Incompatible return type
    // TODO Auto-generated method stub

    apiRootObject apiRootObject = null;
    apiRootObject tempApiRootObject = null;
    List<apiRootObject> myList=new ArrayList<apiRootObject>();
    int page = 0;

    try {
    do {
    HttpGet get = new HttpGet(params[0] + page);
    HttpClient client = new DefaultHttpClient();
    HttpResponse response = client.execute(get);
    HttpEntity entity = response.getEntity();
    String result = EntityUtils.toString(entity);

    jsonObject = new JSONObject(result);
 //handling json exceptions
   if(jsonObejct!=null && !jsonObject.isNull("page")&&..){
    tempApiRootObject.page=jsonObject.getString("page");
    tempApiRootObject.last_page=jsonObject.getString("last_page");
    //here we put the results in the tempsApiRootObject
    JSONArray ja = jsonObject.getJSONArray("results");
    for (int i = 0; i < ja.length(); i++) {
    JSONObject c = ja.getJSONObject(i);//this is an item
    int data_id= c.getInt("data_id");
    String name= c.getString("name");
    //the other values
    //here you add them in your arraylist of <apiResults> (*)
    }
    //and here we add the arraylist in (*) to tempApiRootObject
    myList.add(tempApiRootObject);
    /* if (apiRootObject == null){
    apiRootObject = tempApiRootObject;
    }
    else{
    apiRootObject.results.addAll(tempApiRootObject.results);
    apiRootObject.count += tempApiRootObject.count;
    }*/ i didn't understand this
    }page++;
    }

    while(tempApiRootObject.last_page != tempApiRootObject.page);

    } catch (ClientProtocolException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    } catch (JSONException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }

    return myList// apiRootObject;
    }

还有这个

    public void onResponse(List<apiRootObject> myList) {  
    for(int i=0;i++;i<myList.size()){ 
            apiRootObject resultClass =myList.get(i);
//do something 
}
        }