静态变量不会改变并被替换为“”

Question

我的应用程序是一个简单的单词拼图游戏，因此它的关卡是从 Json 网络服务中获取的，使用 AsyncTask 类我可以在 doInBackground 和 onPostExecute 方法中获取数据，我使用FetchData 类中的局部变量来保存获取的数据，数据只是 6 个字符串，即图像 URL 和关卡 id，以及 4 个用于按钮的单词，here 是游戏界面，如您所见有4个按钮，每个按钮都有一个单词，玩家必须通过查看图片找到它。

所以当玩家找到例如 1 个单词并离开应用程序并关闭它时，必须保存玩家找到的单词，当他返回 LevelActivity 时，他应该通过找到更多 3 个单词来继续关卡。

问题： 是当我找到一个单词并且该单词显示（因此必须保存）时，当我关闭应用程序并返回 this 时发生，这取决于我发现的测试那些影响数据滞后的代码行

注意：每当我（手动）重新加载活动时，一切都会变得好起来，而不是在重新创建活动后显示一个空按钮。

使用的数据获取方式：in onCreate & onResume

//This is in LevelActivity.java:

//These methods checks if the button is answered previously or not (button1/button2... variables are true when a word is answered)

  public void checkButton1() {

        if (button1) {
            wordButton1.setText(button1Word); //<--- Here if I changed it to .setText("Test") 
          //the lag will disappear and the button will show "Test" (without the quotation) and everything's good
          //So the problem is when I use .setText(button1Word); that is the word fetched from Json web service.
          //it doesn't throw NullPointerException and it doesn't show the word
          //but what? it set the text to " "? Why?

          //Note other buttons are the same thing too

        }

    }

    public void checkButton2() {

        if (button2) {
            wordButton2.setText(button2Word);
        }
    }

    public void checkButton3() {

        if (button3) {
            wordButton3.setText(button3Word);
        }
    }

    public void checkButton4() {

        if (button4) {
            wordButton4.setText(button4Word);
        }
    }

//This is FetchData class that fetches the data from Json web service (full code)

package com.example.wordspuzzlejsontest;

import android.content.Context;
import android.os.AsyncTask;
import com.squareup.picasso.Picasso;
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> {

//Local variable that are used to hold fetched data to transfer them to LevelActivity with static variables
    static int currentLevel = 0;
    String w1;
    String w2;
    String w3;
    String w4;
    String data = "";
    String id;
    String img;
    Context context;

    @Override
    protected Void doInBackground(Void... voids) {
        try {
            URL url = new URL("https://api.jsonbin.io/b/5e42776dd18e4016617690ce/7");
            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);

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

            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++;

        //Loading the words data to buttons
        LevelActivity.levelID = String.valueOf(levelId);
        LevelActivity.imageURL = img;
        LevelActivity.button1Word = w1;
        LevelActivity.button2Word = w2;
        LevelActivity.button3Word = w3;
        LevelActivity.button4Word = w4;

        //Loading level image and level number on the screen
        LevelActivity.levelIdTextView.setText(LevelActivity.levelID);
        loadLevelImage();
    }

    public void loadLevelImage() {

        Picasso.with(context).load(LevelActivity.imageURL).placeholder(R.drawable.loading)
                .error(R.drawable.loading)
                .into(LevelActivity.imageView, new com.squareup.picasso.Callback() {

                    @Override
                    public void onSuccess() {

                    }

                    @Override
                    public void onError() {

                    }
                });
    }

}

感谢您查看我的回答：如果您需要任何其他代码，请告诉我。

Answer 1

onPostExecute() 调用结束时

checkButton1()
checkButton2()
checkButton3()
checkButton4()

不见了。因此，按钮无法知道新值，因此保持为空。