java - Android java从url解析json到对象列表

Question

我想连接到一个 Api url，检索 json 并将所有内容存储在一个对象列表中。 Here is an example url 可以作为 Json 返回的内容。注意开头有一个count、page 和last_page。这些是页面上有多少项目、您所在的页面以及总共有多少页(一页最多 50 个计数)。不特定的搜索很容易返回多达 1000 页的结果

我在 c# 中有这段代码，它可以完美地工作，但在搜索和尝试了很长时间之后，我不知道如何在 Android java 中重新创建它。

这是 api_handler.cs

public class api_Handler
    {
        public static RootObject objFromApi_idToName(string spidyApiUrl, int page){
            RootObject rootObject = null;
            RootObject tempRootObject = null;

            do{
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(spidyApiUrl + "/" + page);

                WebResponse response = request.GetResponse();
                using (Stream responseStream = response.GetResponseStream()){
                    StreamReader reader = new StreamReader(responseStream, Encoding.UTF8);
                    var jsonReader = new JsonTextReader(reader);
                    var serializer = new JsonSerializer();
                    tempRootObject = serializer.Deserialize<RootObject>(jsonReader);

                    if (rootObject == null){
                        rootObject = tempRootObject;
                    }
                    else{
                        rootObject.results.AddRange(tempRootObject.results);
                        rootObject.count += tempRootObject.count;
                    }
                }
                page++;
            }

            while (tempRootObject != null && tempRootObject.last_page != tempRootObject.page);
            return rootObject;
        }
}

我在 main_form.cs 中这样调用的

// url will become = http://www.gw2spidy.com/api/v0.9/json/item-search/ + textbox.text
// full example = http://www.gw2spidy.com/api/v0.9/json/item-search/Sunrise
    string spidyApiUrl = String.Format("{0}{1}/api/{2}/{3}/{4}/{5}", Http, spidyHost, spidyApiVersion, format, spidyApiType, dataId);
    var spidyApi_idByName = api_Handler.objFromApi_idToName(spidyApiUrl, startPage);

当然还有构造函数，尽管我认为这些构造函数对于包含在问题中并不重要。

public class Result
    {
        public int data_id { get; set; }
        public string name { get; set; }
        public int rarity { get; set; }
        public int restriction_level { get; set; }
        public string img { get; set; }
        public int type_id { get; set; }
        public int sub_type_id { get; set; }
        public string price_last_changed { get; set; }
        public int max_offer_unit_price { get; set; }
        public int min_sale_unit_price { get; set; }
        public int offer_availability { get; set; }
        public int sale_availability { get; set; }
        public int sale_price_change_last_hour { get; set; }
        public int offer_price_change_last_hour { get; set; }
    }

    public class RootObject
    {
        public int count { get; set; }
        public int page { get; set; }
        public int last_page { get; set; }
        public int total { get; set; }
        public List<Result> results { get; set; }
    }

如何将 c# 中的工作代码转换为 android java？或者从头开始是更好的主意(我仍然需要一些指导，因为我尝试了很多次都没有成功)

还有:

在 PC 上的 C# 中，这将在一个完美的可接受时间内运行，对于 1000x50 的对象，这可能会加载 1-2 秒，这是一个非常不明确的搜索。这些非特定搜索当然会发生，因为它是根据用户输入确定的，但不会经常发生，正常搜索可能是 1 页到 50 页。手机是否能够在可接受的时间内执行此操作？

长话短说连接到 api > 检索所有 json 值 > 将所有值存储在对象列表中 > 发送回 activity.java

Answer 1

在 Android 中使用 AsyncTask

Activity :

public class MainActivity extends Activity implements onResponse {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    String URL = "http://www.gw2spidy.com/api/v0.9/json/item-search/Sunrise";
    AsyncFetch parkingInfoFetch = new AsyncFetch(this);
    parkingInfoFetch.setOnResponse(this);
    parkingInfoFetch.execute(URL);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.activity_main, menu);

    return true;
}

@Override
public void onResponse(JSONObject object) {
    Log.d("Json Response", "Json Response" + object);

    ResultClass resultClass = new ResultClass();

    try {
        resultClass.setCount(object.getInt("count"));
        resultClass.setPage(object.getInt("page"));
        resultClass.setLast_page(object.getInt("last_page"));
        resultClass.setTotal(object.getInt("total"));
        JSONArray array = new JSONArray(object.getString("results"));
        for (int i = 0; i < resultClass.getTotal(); i++) {
            JSONObject resultsObject = array.getJSONObject(i);
            resultClass.setData_id(resultsObject.getInt("data_id"));
            resultClass.setName(resultsObject.getString("name"));
            resultClass.setRarity(resultsObject.getInt("rarity"));
            resultClass.setRestriction_level(resultsObject
                    .getInt("restriction_level"));
            resultClass.setImg(resultsObject.getString("img"));
            resultClass.setType_id(resultsObject.getInt("type_id"));
            resultClass.setSub_type_id(resultsObject.getInt("sub_type_id"));
            resultClass.setPrice_last_changed(resultsObject
                    .getString("price_last_changed"));
            resultClass.setMax_offer_unit_price(resultsObject
                    .getInt("max_offer_unit_price"));
            resultClass.setMin_sale_unit_price(resultsObject
                    .getInt("min_sale_unit_price"));
            resultClass.setOffer_availability(resultsObject
                    .getInt("offer_availability"));
            resultClass.setSale_availability(resultsObject
                    .getInt("sale_availability"));
            resultClass.setSale_price_change_last_hour(resultsObject
                    .getInt("sale_price_change_last_hour"));
            resultClass.setOffer_price_change_last_hour(resultsObject
                    .getInt("offer_price_change_last_hour"));

        }

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

}}

异步任务类:

public class AsyncFetch extends AsyncTask<String, Void, JSONObject> {

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

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

public onResponse getOnResponse() {
    return onResponse;
}

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

@Override
protected JSONObject doInBackground(String... params) {
    // TODO Auto-generated method stub
    try {
        HttpGet get = new HttpGet(params[0]);
        HttpClient client = new DefaultHttpClient();

        HttpResponse response = client.execute(get);
        HttpEntity entity = response.getEntity();
        String result = EntityUtils.toString(entity);
        jsonObject = new JSONObject(result);
    } 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 jsonObject;
}

@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);
}

模型类:

public class ResultClass {

public int data_id;
public String name;
public int rarity;
public int restriction_level;
public String img;
public int type_id;
public int sub_type_id;
public String price_last_changed;
public int max_offer_unit_price;
public int min_sale_unit_price;
public int offer_availability;
public int sale_availability;
public int sale_price_change_last_hour;
public int offer_price_change_last_hour;

public int count;
public int page;
public int last_page;
public int total;

public int getData_id() {
    return data_id;
}

public void setData_id(int data_id) {
    this.data_id = data_id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public int getRarity() {
    return rarity;
}

public void setRarity(int rarity) {
    this.rarity = rarity;
}

public int getRestriction_level() {
    return restriction_level;
}

public void setRestriction_level(int restriction_level) {
    this.restriction_level = restriction_level;
}

public String getImg() {
    return img;
}

public void setImg(String img) {
    this.img = img;
}

public int getType_id() {
    return type_id;
}

public void setType_id(int type_id) {
    this.type_id = type_id;
}

public int getSub_type_id() {
    return sub_type_id;
}

public void setSub_type_id(int sub_type_id) {
    this.sub_type_id = sub_type_id;
}

public String getPrice_last_changed() {
    return price_last_changed;
}

public void setPrice_last_changed(String price_last_changed) {
    this.price_last_changed = price_last_changed;
}

public int getMax_offer_unit_price() {
    return max_offer_unit_price;
}

public void setMax_offer_unit_price(int max_offer_unit_price) {
    this.max_offer_unit_price = max_offer_unit_price;
}

public int getMin_sale_unit_price() {
    return min_sale_unit_price;
}

public void setMin_sale_unit_price(int min_sale_unit_price) {
    this.min_sale_unit_price = min_sale_unit_price;
}

public int getOffer_availability() {
    return offer_availability;
}

public void setOffer_availability(int offer_availability) {
    this.offer_availability = offer_availability;
}

public int getSale_availability() {
    return sale_availability;
}

public void setSale_availability(int sale_availability) {
    this.sale_availability = sale_availability;
}

public int getSale_price_change_last_hour() {
    return sale_price_change_last_hour;
}

public void setSale_price_change_last_hour(int sale_price_change_last_hour) {
    this.sale_price_change_last_hour = sale_price_change_last_hour;
}

public int getOffer_price_change_last_hour() {
    return offer_price_change_last_hour;
}

public void setOffer_price_change_last_hour(int offer_price_change_last_hour) {
    this.offer_price_change_last_hour = offer_price_change_last_hour;
}

public int getCount() {
    return count;
}

public void setCount(int count) {
    this.count = count;
}

public int getPage() {
    return page;
}

public void setPage(int page) {
    this.page = page;
}

public int getLast_page() {
    return last_page;
}

public void setLast_page(int last_page) {
    this.last_page = last_page;
}

public int getTotal() {
    return total;
}

public void setTotal(int total) {
    this.total = total;
}

希望对你有帮助