java - jsonbin.io 获取 Json 数据滞后问题

Question

我正在开发一个简单游戏的应用程序，所以这里有一个 picture对于我的 UI，问题是当我使用 Json Web 服务获取级别时，第一次从 activity_level_list 选择级别，图片和关卡编号不显示，只有4个字有效，但图像和关卡编号均不显示，如 this .

NOTE: The image URL variable is null (because of the lag that happens the first time I open first level activity) so an error happen (that's why it shows ic_launcher instead of showing the level picture).

所以，我说问题是“滞后”，因为当我返回 LevelList 并单击级别 1 时，会获取图片和级别编号，一切都会变得很好。

如何让图像和关卡 ID 在第一次打开 Activity 时同时出现？

NOTE: I use jsonbin.io for data fetching.

这是我的 Json 数据获取类:

import android.os.AsyncTask;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

public class FetchData extends AsyncTask<Void,Void,Void> {

    String update = "4";

    String data ="";

    String id;
    String img;
    String w1;
    String w2;
    String w3;
    String w4;


    @Override
    protected Void doInBackground(Void... voids) {
        try {
            URL url = new URL("https://api.jsonbin.io/b/5e42776dd18e4016617690ce/" + update);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            String line = "";
            while(line != null){
                line = bufferedReader.readLine();
                data = data + line;
            }

            JSONArray JA = new JSONArray(data);

//            for(int i = 0 ;i < JA.length(); i++) {

                JSONObject JO = (JSONObject) JA.get(1);

                        id = (String) JO.get("id");
                        img = (String) JO.get("img");
                        w1 = (String) JO.get("w1");
                        w2 = (String) JO.get("w2");
                        w3 = (String) JO.get("w3");
                        w4 = (String) JO.get("w4");

//            }

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (JSONException e) {
            e.printStackTrace();
        }

        return null;
    }

    @Override
    protected void onPostExecute(Void aVoid) {
        super.onPostExecute(aVoid);

        int levelId = Integer.parseInt(id);
        levelId++;

        LevelActivity.levelID = String.valueOf(levelId);
        LevelActivity.imageURL = img;
        LevelActivity.button1Word = w1;
        LevelActivity.button2Word = w2;
        LevelActivity.button3Word = w3;
        LevelActivity.button4Word = w4;

    }


}

谢谢^-^

Answer 1

I just needed to update the image and level text view number in onPostExecute method to make it load from the first time. Answer by NIKHIL AGGARWAL